TECHNICAL COMMITTEE 215:

"Electrotechnical Aspects of Telecommunication Equipment"

Project: 79732

Title: prEN 50600‑2‑2 Ed3

Contents Page

European foreword 5

Introduction 6

1 Scope 8

2 Normative references 8

3 Terms, definitions and abbreviations 9

3.1 Terms and definitions 9

3.2 Abbreviations 13

3.3 Symbols 14

4 Conformance 14

5 Power supply and distribution within data centres 14

5.1 Functional elements 14

5.1.1 General 14

5.1.2 Power supply to the data centre 15

5.1.3 Power distribution within the data centre 16

5.2 Dimensioning of power distribution systems 18

6 Availability 18

6.1 General 18

6.2 Power supply 19

6.2.1 Capacity planning 19

6.2.2 Availability of the utility supply 21

6.2.3 Power quality 22

6.2.4 Load presented to the utility supply 22

6.2.5 Equipment 23

6.2.6 Availability Class design options 25

6.3 Power distribution 31

6.3.1 Capacity planning 31

6.3.2 Power quality 33

6.3.3 Equipment 33

6.3.4 Availability Class design options 34

6.4 Incorporation of low voltage direct current distribution 38

6.5 Additional considerations 38

6.5.1 Residual current measurement 38

6.5.2 Type of system earthing in low-voltage installations 39

6.5.3 Lightning and surge protection 39

6.5.4 Segregation of power distribution cabling and information technology cabling 39

6.6 Emergency power off 39

6.6.1 Requirements 39

6.6.2 Recommendations 39

6.7 Control system capacity planning with respect to resilience 39

7 Physical security 40

7.1 General 40

7.2 Protection against unauthorized access 40

7.2.1 Power supply 40

7.2.2 Power distribution 40

7.2.3 Attachment of unauthorized end-equipment 40

7.3 Internal environmental events 40

7.3.1 Power supply 40

7.3.2 Power distribution 40

7.4 External environmental events 41

8 Energy efficiency enablement and power distribution 41

8.1 General 41

8.2 Quality of measurements 42

8.2.1 Requirements 42

8.2.2 Recommendations 43

8.3 Granularity Level 1 43

8.4 Granularity Level 2 43

8.5 Granularity Level 3 43

8.6 Cabling infrastructure to support energy efficiency enablement 43

Bibliography 44

Tables

Table 1 — Typical functional elements of power supply and distribution 15

Figures

Figure 1 — Schematic relationship between EN 50600 series of documents 7

Figure 2 — Power supply functional elements 16

Figure 3 — Types of connection points served by the power distribution system 17

Figure 4 — Example of a single path to primary distribution equipment with a single source (Class 1) 27

Figure 5 — Example of a single path to primary distribution equipment with a redundant source (Class 2) 27

Figure 6 — Example of multiple paths to primary distribution equipment with a redundant source (Class 3) 29

Figure 7 — Example of a multiple path to primary distribution equipment with multiple sources (Class 4) 30

Figure 8 — Example of single path power distribution system (Class 1) 35

Figure 9 — Example of single path power distribution system with redundancy (Class 2) 36

Figure 10 — Example of multiple paths providing a concurrent/repair operate solution (Class 3) 37

Figure 11 — Example of a multiple path, fault tolerant solution except during maintenance (Class 4) 38

Figure 12 — Possible measurement points 42

European foreword

This document (prEN 50600‑2‑2:2026) has been prepared by CLC/TC 215 “Electrotechnical aspects of telecommunication equipment”.

This document is currently submitted to the Enquiry.

This document will supersede EN 50600‑2‑2:2019.

prEN 50600‑2‑2:2026 includes the following significant technical changes with respect to EN 50600‑2‑2:2019:

a) the whole document has been revised technically and editorially, aligning with EN 50600‑1 and EN 50600‑2‑3;

b) resource enablement aspects included;

c) several terms and definitions (Clause 3) revised, e.g. “demarcation point” replaced by “virtual point” and “socket” replaced by the more general term “termination point”;

d) Clause 5 updated, e.g. regarding energy efficiency and environmental impact considerations;

e) Clause 6 updated: new elements include provisioning, forecasting and management of ICT equipment and facility infrastructure for capacity planning; resilience criteria based on KPIs; power quality requirements and recommendations revised; subclause 6.7 on control system capacity planning added.

f) Clause 7 editorially improved;

g) Clause 8 revised, in particular with respect to the quality of measurements and the presentation of Granularity Level requirements.

Introduction

The unrestricted access to internet-based information demanded by the information society has led to an exponential growth of both internet traffic and the volume of stored/retrieved data. Data centres are housing and supporting the information technology and network telecommunications equipment for data processing, data storage and data transport. They are required both by network operators (delivering those services to customer premises) and by enterprises within those customer premises.

Data centres usually need to provide modular, scalable and flexible facilities and infrastructures to easily accommodate the rapidly changing requirements of the market. In addition, energy consumption and water/resource usage of data centres has become critical both from an environmental point of view (reduction of environmental footprint) and with respect to economical considerations (cost of energy) for the data centre operator.

The implementation of data centres varies in terms of:

a) purpose (enterprise, co-location, co-hosting or network operator facilities);

b) security level;

c) physical size;

d) accommodation (mobile, temporary and permanent constructions).

The needs of data centres also vary in terms of availability of service, the provision of security and the objectives for energy efficiency. These needs and objectives influence the design of data centres in terms of building construction, power distribution, environmental control, telecommunications cabling and physical security as well as the operation of the data centre. Effective management and operational information is required to monitor achievement of the defined needs and objectives.

Recognizing the substantial resource consumption, particularly of energy, of larger data centres, it is also important to provide tools for the assessment of that consumption both in terms of overall value and of source mix and to provide Key Performance Indicators (KPIs) to evaluate trends and drive performance improvements.

At the time of publication of this document, the EN 50600 series have been designed as a framework of standards, technical specifications and technical reports covering the design, the operation and management, the key performance indicators for energy efficient operation of the data centre as well as a maturity model for energy management and environmental sustainability.

This series of documents specifies requirements and recommendations to support the various parties involved in the design, planning, procurement, integration, installation, operation and maintenance of facilities and infrastructures within data centres. These parties include:

1) owners, operators, facility managers, ICT managers, project managers, main contractors;

2) consulting engineers, architects, building designers and builders, system and installation designers, auditors, test and commissioning agents;

3) facility and infrastructure integrators, suppliers of equipment;

4) installers, maintainers.

The inter-relationship of the documents within the EN 50600 series is shown in Figure 1.

Figure 1 — Schematic relationship between EN 50600 series of documents

EN 50600‑1 introduces the general concepts relevant for the design and operation of data centres.

EN 50600‑2-X documents define the requirements for the data centre design and specify requirements and recommendations for particular facilities and infrastructures to support the relevant classification for “availability”, “physical security” and “energy efficiency enablement” selected from EN 50600‑1.

EN 50600‑3‑1 specifies requirements and recommendations for data centre operations, processes and management.

EN 50600‑4-X documents specify requirements and recommendations for key performance indicators (KPIs) used to assess and improve the resource usage efficiency and effectiveness, respectively, and criteria of resilience of a data centre.

CLC/TS 50600‑5‑1 specifies the maturity model for energy management and environmental sustainability and refers amongst others to EN 50600‑4-X for KPIs as appropriate.

At the time of publication of this document, EN 50600‑2 series comprises the following documents:

EN 50600‑2‑1: Information technology — Data centre facilities and infrastructures — Part 2-1: Building construction;

EN 50600‑2‑2: Information technology — Data centre facilities and infrastructures — Part 2-2: Power supply and distribution;

EN 50600‑2‑3: Information technology — Data centre facilities and infrastructures — Part 2-3: Environmental control;

EN 50600‑2‑4: Information technology — Data centre facilities and infrastructures — Part 2-4: Telecommunications cabling infrastructure;

EN 50600‑2‑5: Information technology — Data centre facilities and infrastructures — Part 2-5: Security systems;

CLC/TS 50600‑2‑10: Information technology — Data centre facilities and infrastructures — Part 2-10: Earthquake risk and impact analysis.

This document, EN 50600‑2‑2, addresses facilities and infrastructures for power supplies to, and power distribution within, data centres together with the interfaces for monitoring the performance of those facilities and infrastructures in line with EN 50600‑3‑1 and the EN 50600‑4 series (in accordance with the requirements of EN 50600‑1). The line diagrams used in certain Figures are not intended to replace the more familiar electrical circuit diagrams associated with power supply and distribution systems.

This document is intended for use by and collaboration between architects, building designers and builders, system and installation designers.

This series of European Standards does not address the selection of information technology and network telecommunications equipment, software and associated configuration issues.

This document addresses power supplies to, and power distribution within, data centres based upon the criteria and classifications for “availability”, “physical security” and “resource and energy efficiency enablement” within EN 50600‑1.

This document specifies requirements and recommendations for the following:

a) power supplies to data centres;

b) power distribution systems to all equipment within data centres;

c) telecommunications infrastructure bonding;

d) lightning protection;

e) devices for the measurement of the energy consumption and power quality characteristics at points along the power distribution system and their integration within management tools.

Safety and electromagnetic compatibility (EMC) requirements are outside the scope of this document and are covered by other standards and regulations. However, information given in this document can be of assistance in meeting these standards and regulations.

The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

EN 13160 (all parts), Leak detection systems

EN 50160:2022,^[1] Voltage characteristics of electricity supplied by public electricity networks

EN 50174‑2, Information technology - Cabling installation - Part 2: Installation planning and practices inside buildings

EN 50174‑3, Information technology - Cabling installation - Part 3: Installation planning and practices outside buildings

EN 50310, Telecommunications bonding networks for buildings and other structures

EN 50600‑1, Information technology - Data centre facilities and infrastructures - Part 1: General concepts

EN 50600‑2‑3, Information technology - Data centre facilities and infrastructures - Part 2-3: Environmental control

EN 50600‑2‑4, Information technology – Data centre facilities and infrastructures – Part 2-4: Telecommuni-cations cabling infrastructure

EN 50600‑2‑5, Information technology - Data centre facilities and infrastructures - Part 2-5: Security systems

EN IEC 60076‑11, Power transformers - Part 11: Dry-type transformers

EN IEC 60947 (all parts),^[2] Low-voltage switchgear and controlgear (IEC 60947)

EN IEC 61000‑2‑4:2024, Electromagnetic compatibility (EMC) - Part 2-4: Environment - Compatibility levels in power distribution systems in industrial locations for low-frequency conducted disturbances

EN IEC 61439 (all parts),^[3] Low-voltage switchgear and controlgear assemblies (IEC 61439)

EN IEC 61557‑12:2022, Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC - Equipment for testing, measuring or monitoring of protective measures - Part 12: Power metering and monitoring devices (PMD)

EN 61869‑2:2012, Instrument transformers - Part 2: Additional requirements for current transformers

EN IEC 62040 (all parts),^[4] Uninterruptible power systems (UPS) (IEC 62040)

EN 62053‑21:2021, Electricity metering equipment (a.c.) - Particular requirements - Part 21: Static meters for active energy (classes 1 and 2)

EN IEC 62271‑200, High-voltage switchgear and controlgear - Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV

EN IEC 62305 (all parts), Protection against lightning (IEC 62305)

EN IEC 62305‑4, Protection against lightning - Part 4: Electrical and electronic systems within structures

EN 62586‑1:2017, Power quality measurement in power supply systems - Part 1: Power quality instruments (PQI)

EN 62586‑2:2017,^[5] Power quality measurement in power supply systems – Part 2: Functional tests and uncertainty requirements

EN IEC 62974‑1, Monitoring and measuring systems used for data collection, aggregation and analysis - Part 1: Device requirements

EN 88528‑11, Reciprocating internal combustion engine driven alternating current generating sets - Part 11: Rotary uninterruptible power systems - Performance requirements and test methods

HD 60364 (all parts), Low-voltage electrical installations

IEC/TS 60076‑20:2017, Power transformers - Part 20: Energy efficiency

For the purposes of this document, the terms and definitions given in EN 50600‑1 and the following apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/

— ISO Online browsing platform: available at http://www.iso.org/obp

3.1.1

active power

under periodic conditions, mean value, taken over one period T, of the instantaneous power p

Note 1 to entry: Under sinusoidal conditions, the active power is the real part of the complex power S, thus P = Re S.

Note 2 to entry: The coherent SI unit for active power is watt, W.

[SOURCE: IEC 60050‑131:2002, 131-11-42]

3.1.2

additional supply

power supply that provides power in the event of failure of primary and/or secondary supply

3.1.3

apparent power

product of the rms voltage U between the terminals of a two-terminal element or two-terminal circuit and the rms electric current I in the element or circuit S = UI

Note 1 to entry: Under sinusoidal conditions, the apparent power is the modulus of the complex power S, thus S = |S| .

Note 2 to entry: The coherent SI unit for apparent power is voltampere, VA.

[SOURCE: IEC 60050‑131:2002, 131-11-41]

3.1.4

capacitive load

load that is capacitive, so that the alternating current is out of phase with and leads the voltage

3.1.5

catenary

wire hung at a specific tension between supporting structures of power cabling

3.1.6

connection point

socket/outlet or a connection enabling supply of power to attached/connected equipment

Note 1 to entry: This can be a de-mateable or a hardwired connection.

3.1.7

diverse route

alternative, separate, pathway intended to provide adequate segregation from another pathway, in order to provide resilient service provision in the event of physical damage to one of the pathways

3.1.8

dual-corded equipment

equipment served by multiple power supply input interfaces

3.1.9

emergency power off

designated device to provide emergency switching which disconnects power from one or more data centre facilities, infrastructures or spaces

Note 1 to entry: The configuration and function of emergency power off devices can be subject to national or local regulations.

3.1.10

fire compartment

discrete zone designed to contain a fire within that zone

3.1.11

high voltage

voltage with a nominal rms-value 36 kV < U_n ≤ 150 kV

Note 1 to entry: Whereas in most other standards HV covers the total AC-voltage- range > 1 kV, for the purpose of this document this range is separated in the three parts MV, HV, and EHV.

[SOURCE: EN 50160:2022, 3.2.2]

3.1.12

integrated energy storage

IES

uninterruptible power supply, integrated inside electric devices, e.g. ICT equipment

3.1.13

inductive load

load that is inductive, so that the alternating current is out of phase with and lags behind the voltage

3.1.14

ICT load

electrical consumption of all the information, communication technology equipment, providing data storage, processing and transport services

3.1.15

load factor

ratio, expressed as a numerical value or as a percentage, of the consumption within a specified period (year, month, day, etc.), to the consumption that would result from continuous use of the maximum or other specified demand occurring within the same period

Note 1 to entry: This term should not be used without specifying the demand and the period to which it relates.

Note 2 to entry: The load factor for a given demand is also equal to the ratio of the utilization time to the time in hours within the same period.

[SOURCE: IEC 60050‑691:1973, 691-10-02]

3.1.16

locally protected connection point

socket/outlet or a connection which continues to deliver power to connected equipment for a defined period following failure of power supply and distribution equipment by means of a battery supply or UPS adjacent to, or co-located with, those connections

3.1.17

low voltage

voltage whose nominal r.m.s. value is U_n ≤ 1 kV

[SOURCE: EN 50160:2010, 3.9]

3.1.18

main-tie-tie-main

electrical connection between two power supply or power distribution circuits which allows current to flow in either direction and containing two circuit breakers enabling maintenance while one of the circuits is active

3.1.19

medium voltage

voltage whose nominal r.m.s. value is 1 kV < U_n ≤ 36 kV

Note 1 to entry: Because of existing network structures, in some countries the boundary between MV and HV can be different.

[SOURCE: EN 50160:2010, 3.11]

3.1.20

pathway

defined route for cables between termination points

[SOURCE: EN 50174‑1:2018, 3.1.31]

3.1.21

power factor

under periodic conditions, ratio of the absolute value of the active power P to the apparent power S: λ = |P|/S

Note 1 to entry: The ratio of the active (real) power flowing to the load to the apparent power (as a result of the capacitive or inductive nature of the load) and is a dimensionless number between 0 and 1.

[SOURCE: IEC 60050‑131:2002, 131-11-46, modified: Note 1 to entry reworded]

3.1.22

primary distribution equipment

equipment which is required to manage, control and/or convert incoming power supplies (primary, secondary and, where appropriate, additional) in a form suitable for distribution by secondary distribution equipment

3.1.23

primary supply

principal power supply that provides power to the data centre under normal operating conditions

3.1.24

protected connection point

socket/outlet or a connection which continues to deliver power to connected equipment for a defined period following failure of power supply and distribution equipment

3.1.25

secondary distribution equipment

equipment which is required to manage, control and distribute the power provided by the primary distribution equipment to the short-break, protected and unprotected connection points within the data centre and to the tertiary distribution equipment

Note 1 to entry: The power supply can be single-phase AC, three-phase AC or DC. If there is a change from 3-phase to 1-phase supply, this is generally achieved at the secondary distribution equipment that is served directly from the primary distribution equipment.

3.1.26

secondary supply

power supply independent from the primary supply, and that is continuously available to be used to provide power to the data centre

Note 1 to entry: A second feed to a separate transformer from the same grid is not a secondary supply.

3.1.27

short-break connection point

sockets/outlet or a connection which, upon failure of power supply and distribution equipment, will be provided with power from an additional supply after a defined period

3.1.28

tertiary distribution equipment

power supply equipment, typically accommodated within the cabinets, frames and racks of the data centre spaces, which directly feeds the protected connection points therein

3.1.29

unprotected connection point

socket/outlet or a connection which fails to deliver power to connected equipment following failure in power supply or distribution equipment

3.1.30

virtual point

virtual interface between the power supply system and power distribution system infrastructures

For the purposes of this document, the abbreviations given in EN 50600‑1 and the following apply.

For the purposes of this document, the following symbols apply.

For a data centre to conform to this document:

a) it shall feature a power supply and distribution design solution that meets both the general requirements, and the required Availability Class, of Clause 6;

b) the environmental controls applied to the spaces accommodating the power supply and distribution system within the premises and serving the data centre shall be in accordance with EN 50600‑2‑3;

c) it shall feature an approach to physical security in relation to the power supply and distribution solution that meets the requirements of Clause 7;

d) it shall feature an energy efficiency enablement solution that meets the requirements of the relevant Granularity Level of Clause 8;

e) the telecommunications bonding system within the computer room and telecommunications spaces of the data centre shall be in accordance with the local mesh bonding requirements of EN 50310;

f) where lightning protection is required, it shall be in accordance with the EN IEC 62305 series and EN 50310;

g) the design of low voltage (LV) power supply and distribution installations shall be in accordance with the HD 60364 series;

The Availability Class of the power distribution infrastructure is based on the required Availability Class of the data centre. The power supply infrastructure shall be of the same or higher Availability Class.

The distribution of electrical power is one of the most important aspects of data centre infrastructure. Disturbances of power supply voltage, current and frequency have a direct effect on the operational safety of the data centre infrastructure and its availability.

The functional elements of power supply and distribution to the data centre are described as:

— sources: e.g. primary, secondary or additional supplies;

— devices: e.g. supply transfer switchgear;

— paths: pathways, spaces and cabling.

Typical sources and devices of power supply to and distribution within data centres are described in Table 1. The requirements and recommendations for the provision of physical security to the spaces accommodating the functional elements are described in Clause 7.

Implementations need not include all of the elements listed in Table 1. Also the types of equipment comprising certain functional elements can exist in both the area of supply and distribution.

Energy efficiency and environmental impact should be considered in accordance with CLC/TS 50600‑5‑1.

Table 1 — Typical functional elements of power supply and distribution

The power supply schematic of Figure 2 indicates two implementations. Figure 2 a) shows the minimum implementation comprising a single source (primary power supply) only. Figure 2 b) shows multiple sources and includes a secondary supply and also an additional supply that provides power to relevant equipment in the data centre.

The primary and secondary supplies are typically provided from transformers which can be within the premises containing the data centre (and can be owned by either the utility or the data centre premises owner) or external and owned by the utility (and not considered to be a functional element of the data centre).

An additional supply is one of the possible functional elements for supplying the data centre with power. The additional supply will provide energy in case the primary and secondary supplies are not available. Therefore, parameters such as the sizing, the basic design as well as the availability of the overall power supply concept shall be precisely planned.

While the additional supply is typically a locally managed supply, it can be provided by a separate utility supply that it is protected from failures in the primary or secondary supplies. If the additional supply is a locally managed supply, with no connection to the utility, it shall be designed to be able to replace the power supply(ies) in case of their failure.

The primary distribution equipment can also contain transformers.

a) minimum implementation

b) multiple sources

Figure 2 — Power supply functional elements

The primary distribution equipment provides the interface between the supply and distribution areas.

The input to the primary distribution equipment can be LV and/or MV.

The output from the primary distribution equipment can be LV and/or MV depending upon the size of the premises and the input requirements of any uninterruptible power system (UPS) or DC supply equipment installed between the primary and secondary distribution equipment.

The functional elements of the power distribution within the data centre are described as:

— devices: e.g. primary, secondary and tertiary distribution equipment, UPS;

— paths: pathways, spaces and cabling that connects the devices.

The distribution system is shown in Figure 3. The power is distributed via one or more instances of secondary distribution equipment. These and subsequent figures adopt a system level approach to the implementation.

The input to the secondary distribution equipment can be LV and/or MV.

Equipment within the power distribution system may also contain transformers.

Figure 3 — Types of connection points served by the power distribution system

Within Figure 3 the power is provided to connection points in the distribution area that are categorized as:

1) unprotected connection points: suitable for equipment that is not critical to the function of the data centre (e.g. powering of tools and equipment required for the maintenance of the facility);

2) protected connection points: intended for equipment that is critical to the function of the data centre (e.g. information technology and network telecommunications equipment, certain elements of environmental control and security systems) and which cannot tolerate failure of supply, served by solutions including UPS installed as part of the distribution system;

3) locally protected connection points: intended for equipment served by solutions including UPS or local battery supplies installed at or close to the connection point;

4) short-break connection points (available where the primary and/or secondary power supply is augmented with an additional supply): intended for equipment (e.g. environmental control equipment and certain lighting systems) that is critical to the function of the data centre but which can tolerate a failure of supply for a defined period before the additional supply (e.g. generator) is brought into service.

A combination of short-break connection point and ICT equipment with integrated energy storage can be used to define power distribution path(s) for the different Availability Classes. The necessary autonomy time as well as the resulting impacts, e.g risk of fire, etc. shall be considered in the business and risk analysis (EN 50600‑1) and, if necessary, additional requirements result from it.

A responsible matrix shall be created with regard to the fact if the ICT equipment is not under the control of the data centre owner to ensure the integrity of the selected Availability Class.

The output from the secondary distribution equipment is typically LV. Additional secondary distribution equipment is typically installed if there is a need to change the current capacity of the power supply cabling.

In small data centres, the data centre might only contain the functional elements within the distribution area. That means the primary distribution equipment being elsewhere in the premises and serving the power distribution in the remainder of the premises. In large data centres, primary distribution equipment can be dedicated to the demands of the data centre itself.

The smallest data centres can comprise a single cabinet containing in-cabinet distribution equipment providing protected power supplies to data processing, storage and transport equipment. In such cases the functionality of the secondary distribution equipment is provided by the in-cabinet distribution equipment. It is not necessary to provide any unprotected or short-break connection points within the cabinet.

In the small data centres comprising a limited number of cabinets, frames or racks, the UPS can be installed immediately adjacent to, or within, the tertiary distribution area.

As shown in Figure 2, an additional power supply is in place, e.g. generator. That is intended to deliver short-break power supply and protected supply for an extended period in case of failures of the primary and secondary power supply of the data centre.

The use of secondary power supplies and additional supplies and primary distribution equipment in order to enhance levels of availability are addressed in 6.2.6.

The power supply and distribution systems for a data centre comprise a complex sequence of functional elements in a hierarchical structure. A series of serial and parallel systems convert the power from the primary, secondary or additional supplies and maintaining and/or improving its quality and availability, deliver that power to the mix of end-equipment within the data centre.

The measurement of power supply parameters at the locations described in 6.2.3 (power quality) and Clause 8 (energy efficiency enablement) and the associated monitoring of those parameters and their trends is also able to indicate conditions where demand is threatened by the available capacity.

The power supply and distribution systems within the data centre shall be designed and/or selected in order to provide the required availability of power supply to the end-equipment.

The Availability Class of the power supply and distribution systems shall be at least equal to that required by the Availability Class of the overall set of facilities and infrastructures chosen in accordance with EN 50600‑1.

For the provisioning, forecasting and management of data centre ICT equipment and facility infrastructure for capacity planning the ISO/IEC TS 8236 series should be used.

Subclause 6.2 defines general requirements and recommendations for the design and selection of the power supply system and in terms of Availability Class.

Subclause 6.3 defines general requirements and recommendations for the design of the power distribution system and in terms of Availability Class.

For resilience criteria based on KPIs for availability, reliability, fault tolerance, etc. see CLC/TS 50600‑4‑31.

Sizing

Requirements

The maximum capacity of the power supply system to the data centre shall be sized to accommodate:

a) the maximum planned ICT load (typically, but not necessarily, based upon the published ‘start up’ power requirements supplied by the equipment manufacturers) taking into account allowance for future growth and technology developments (including increased power density of the ICT equipment);

b) the maximum load associated with the environmental control systems serving the data centre spaces taking into account:

1) the extreme design conditions for external ambient temperature and humidity;

2) the Availability Class of the environmental control systems;

c) additional loads including, but not restricted to, security, lighting and building/energy controls, standby consumption for generators and rotary UPS and also battery recharging following a battery discharge;

d) losses in the power distribution system.

During the planning and dimensioning of the power supply, its associated spaces and the selection of sources, devices and paths of the power supply system of the data centre, the following shall also be considered:

e) during construction:

1) temporary/construction power requirements;

f) during operation:

1) initial load (“day one“ of operation);

2) growth of total power load over time;

3) predicted variations and periodicity of active power load and power factor;

4) predicted variations and periodicity of load factor;

5) loads due to energy storage and grid stabilization measures.

g) during inspection (e.g. performance verification, load bank testing etc.) and maintenance of components of the power supply system that are under control of the premises owner;

h) exceptional conditions (i.e. special and/or unusual loads):

1) type of load;

2) occurrence (i.e. continuous, intermittent, cyclical).

The selection of the functional elements of the power distribution system shall provide a solution which takes into account the variability load.

The specification of transformers, generators and controls shall take into consideration the presence of capacitive loads, inductive loads and harmonic current distortion.

The additional supply shall be dimensioned in such a way that it operates reliably under the variable load, taking into account the anticipated/possible power factors of the load. It is therefore necessary to check whether the power load of the data centre is in the capacitive or inductive range. Other possible operating conditions shall also be taken into consideration.

The capacity of any additional supply system shall at least match the capacity planning for the protected, locally protected and short-break connection points as shown in Figure 3.

Where secondary and/or additional supplies are implemented, the balance of the loads shall be considered in the event of failure i.e. is the load to be distributed (evenly or unevenly) on the remaining supplies or is it to be applied, in full, to a single remaining supply. Performance of partially loaded additional supplies (e.g. generators) shall be considered when making such a choice.

A network study for the operating modes shall be prepared for the power distribution systems. This network study includes at least, but is not limited to, load flow calculation, short-circuit current calculations, a protection study.

Loss of primary and/or secondary supply is a mode which shall be considered.

Recommendations

A power quality measurement system should be installed to monitor the power quality of the power distribution system. This system can enable failure prevention and therefore raise availability. The failure prevention can be supported by diagnostics and classification software. The criticality can be prioritized with recommended measures.

Static transfer switches should only be considered following an extensive design review.

Consideration should be given to the status of connection points that provide power to any equipment, such as fuel pumps, necessary to maintain the additional supply.

In some cases when operating high energy switchgear, an arc flash calculation should be provided.

If load banks are used, they should be able to simulate different power factor (leading and lagging) if needed.

Expansion

Requirements

The selection of the functional elements of the power distribution system shall:

a) provide a solution which takes into account the initial load and the maximum planned load while maintaining optimum efficiency;

b) take into account any need to maintain data centre operation during the installation of additional capacity.

Recommendations

Modularity and scalability should be balanced by the number of devices necessary to fulfil availability objectives.

Diversity

Requirements

Availability Class 3 and 4 state requirements and recommendations concerning the duplication and diverse routing of the incoming power supplies.

Recommendations

Where the data centre is provided with multiple power supplies (primary, secondary or additional), the cabling for each power supply between its point of entry to the building accommodating the data centre and its source (e.g. premises entrance or generator space) should be installed in a separate pathway.

An analysis should be employed to assess the balance of risk between the use of overhead catenary pathways (due to climatic effects such as high wind, snow or icing) and the use of underground pathways which can be at risk of accidental excavation.

The pathway within the premises carrying the power supply should be underground unless the risk from accidental excavation is considered higher than the threat from atmospheric disturbance or deliberate or accidental physical damage.

The entrance of each power supply to the building containing the data centre should be:

a) physically segregated to provide a barrier;

NOTE This can be prescribed by national or local regulations.

b) provided with a barrier to prevent ingress of rodents and other animals that can damage the power supply cabling within the building;

c) sufficiently contained to survive an explosion in one transformer housing.

Requirements

The primary and secondary (where provided by a utility) power supply shall be in accordance with EN 50160.

The availability (i.e. continuity of supply) of these supplies shall be assessed during the design process and the design of any additional supplies shall reflect the predicted availability of the primary/secondary supplies.

Using past availability records, the additional supply providing the emergency generation system shall be designed following consideration of:

a) capacity;

b) period of use (intermittent or continuous);

c) load profile (continuous or variable).

Depending on the outcome of this assessment it can be desirable to reverse the roles of primary and additional supplies i.e. where a generator provides the primary supply backed up by the utility power supply.

The design of additional supplies shall be matched to the power distribution system. The support infrastructure for the additional supplies (including capacity of fuel storage capacities) shall be appropriate to the planned service level agreement for replenishment, maintenance and repair of those support infrastructures.

The control systems for additional supplies shall remain functional following failure of primary or secondary power supplies.

Recommendations

A local power supply (e.g. power station or hydro-plant) can be considered as a primary supply if:

a) the availability of the grid connection is considered inadequate and/or;

b) the power quality of the grid supply is considered inadequate.

If a local power supply is used as a primary supply, the impact of any periodic shut-down should be considered. Secondary and additional supplies should be continuously rated for long term maximum-load operation.

General

The voltage, the current and the power factor provide valuable information on the power distribution. In addition, the current of the neutral conductor of three-phase circuits can be calculated or measured.

Requirements

The power quality of primary and secondary supplies shall be in accordance with EN 50160.

The power quality of the additional, non-utility supplies shall be in accordance with EN IEC 61000‑2‑4:2024, Class 2a.

Where monitoring is required, instruments shall be in accordance with class S of EN 62586‑1:2017 and class S of EN 62586‑2:2017^[6].

NOTE 1 Type III PMDs allow advanced power monitoring/network performance.

NOTE 2 Type III PMDs according to EN IEC 61557‑12 can also be used in power stations or substations if they are designed for EMC environments G or EMC environments H, according to EN 62586‑1, respectively.

Where power quality is to be monitored, logged and analysed (including warnings of events), products used for data collection, gathering and analysis shall be in accordance with EN IEC 62974‑1.

Recommendations

The power quality should be measured at least at the supply transfer switchgear for every mode of operation and at the secondary distribution level.

LV power supplies are typically shared by several consumers who act in combination to define, and typically reduce, the power quality. Where concerns exist an analysis of availability and power quality should be obtained and consideration should be given to the monitoring of power quality parameters.

In order to achieve the higher levels of power quality, a data centre should:

a) be connected to the utility supply at the highest possible voltage level;

b) share a sub-station with as few other consumers as possible;

c) not be located near to large consumers of electrical power, such as metals manufacturing and processing, or large electrical machines and electronic drives, such as gas compression facilities.

Where monitoring is required, instruments should be in accordance with class A of EN 62586‑1:2017 and class A of EN 62586‑2:2017^[7].

Requirements

The loads, power factors and harmonics presented to the supply(s) shall remain within the boundaries of any contract of supply and/or be compatible with any local generated and additional supplies.

Recommendations

The following aspects should be taken into account when planning the capacity of the supply with respect to the load;

a) Critical loads:

1) the input power factor and harmonic current spectrum of the chosen UPS;

NOTE As indicated in Figure 2 and Figure 3, UPS or DC supplies are needed in order to ensure adequate power quality to protected connection points feeding the IT, and other critical loads – as a result the load presented to the utility is dominated by the power input stage of the chosen UPS.

2) the input power factor and harmonic current spectrum of the critical load when the UPS is in bypass or another off-line mode;

b) Non-critical loads: the input power factor and harmonic current spectrum of the loads fed by unprotected, short-break and locally protected connection points such as cooling system compressors, pumps and fans - especially if variable speed drives are used.

Transformers

Requirements

Where the primary and/or secondary power supply to the premises accommodating the data centre is HV or MV, any transformers shall be selected to:

a) provide maximum load while running at the extreme design conditions for the ambient temperature for the location without any de-rating for harmonic load currents from UPS (including when under maintenance) or variable speed drives within the facility;

b) stay within their design operating temperature range at maximum load.

The design of transformers and their housings shall take into account the risk and impact of fire.

The design of transformer housing shall prevent ingress of rodents and other animals that can damage the transformer.

Dry type transformers shall be in accordance with EN IEC 60076‑11.

Dry type transformers shall be in accordance with IEC/TS 60076‑20:2017, Table 10, Level 2.

Recommendations

Oil-cooled transformers should only be used where appropriate mitigation of fire risk is employed (e.g. by the use of incombustible oil).

Supply transfer switchgear

General

Supply transfer switchgear for data centre facilities is normally automated with mains-failure monitoring.

Requirements

LV switchgear and control gear shall be in accordance with the EN IEC 60947 series.

LV switchgear and control gear assemblies shall be in accordance with the EN IEC 61439 series.

HV and MV switchgear and control gear shall be in accordance with EN IEC 62271‑200.

If no supply synchronisation is present (see 6.2.5.3.1), transitions shall be open with a delay to prevent a risk of damage to equipment and/or allow for any inductive load decay.

Recommendations

HV and MV supply transfer switchgear should be in accordance with EN IEC 62271‑200:2021,^[8] Category LSC2.

A maintenance-free design should be employed to prevent a shut-down for maintenance on the switchgear.

The LV power supply system should be designed with a high form factor according to EN 61439‑6 to reduce maintenance and expansion interruptions by facilitating to de-energize parts of the supply system without the need to de-energize the whole system.

Where under control of the data centre premises owner the switch gear should be free of fluorinated greenhouse gases.

If communication is in place at HV/MV, it should be in accordance with the EN 61850 series, especially when controlling or power quality monitoring is required.

Additional supplies

Requirements

The selection of continuous rating specification shall be based on an analysis of availability of the primary/secondary supplies.

Where the additional supply comprises generators powered by diesel fuels, the following shall be provided:

a) locally protected connection points for the system controller(s);

b) the provision of a facilities to allow load tests (e.g. operation parallel to the utility or a load bank).

Where the additional supply comprises generators powered by diesel fuels, the following shall be considered in the design of the system to meet the required availability requirements:

c) continuous pre-heating of the diesel engines;

d) monitoring of leakage from fuel storage systems in accordance with the EN 13160 series;

e) redundant starter systems, each consisting of a starter motor and a second independent starting medium;

f) redundant system controllers;

g) monitoring system for the lubricating oil level and a device for refilling the lubricating oil (including during operation);

h) the need for synchronisation between additional, primary and secondary supplies.

Recommendations

Consider reducing the engine generator heater temperature setpoint in accordance with the manufacturer. Block heaters for the standby generators should be controlled to only operate when the temperature conditions warrant it. Manufactures should be consulted to determine risk implications.

Reduce or eliminate the electrical preheat loads for generators and fuel storage by using waste heat from the data centre to maintain temperature in the areas housing generators, fuel storage tanks.

Fuel cleaning and preparation apertures for generators should be implemented.

Uninterruptible power systems (UPS)

Requirements

The following scenarios shall be considered when designing the power supply system associated with UPS:

a) normal operation on UPS fed by utility or by additional supply;

b) load on UPS bypass fed by utility or by additional supply.

The power quality supplied by static UPS shall be in accordance with the appropriate Class of the EN IEC 62040 series. The power quality supplied by dynamic UPS shall be in accordance with the appropriate Class of EN 88528‑11.

In the absence of alternative requirements being specified by the suppliers of equipment to be connected to protected connection points, the power quality between the UPS and the protected connection points shall be in accordance with EN IEC 61000‑2‑4:2024, Class 1.

For more information regarding power quality see 6.2.3.

Recommendations

UPS equipment should be selected to operate in normal mode from the anticipated power quality of the supply and yet supply the protected connection points with conditioned power.

UPS inputs, outputs and bypass(es) should be fitted with surge protection devices (SPDs).

If the UPS is equipped with batteries as a power source, the batteries should be located in a separate fire compartment which is large enough to accommodate the predicted quantity of batteries. It should be possible to install new batteries without disturbing operation.

If the UPS is equipped with Lithium-Ion batteries as a power source, an additional business risk analysis should be considered if additional measures need to be implemented (e.g. separate room, aspiration system, suppression system, pressure relief etc.).

Energy storage and grid stabilization measures

When deploying and using energy storage systems or other electrical equipment like the UPSs or the additional supplies to stabilize or support the public grid, the impact on the availability and resilience of the data centre (e.g. external remote control, equipment lifetime, noise and pollution, space requirements, etc.) shall be considered in the business risk analysis (see EN 50600‑1).

NOTE: ISO/IEC TR 23050 provides details on how to report this mechanism and its impact on PUE and other KPIs.

General

Four design options of increasing Availability Class are specified for the power supply infrastructures:

a) Class 1: Single path to primary distribution equipment and with a single source (see 6.2.6.2)

A Class 1 solution is appropriate where the outcome of the risk assessment deems it acceptable that:

— a single failure in a functional element can result in loss of functional capability;

— planned maintenance can require the load to be shut-down.

In the event of failure of the single source or path the power distribution has no supply.

b) Class 2: Single path to primary distribution equipment and with a redundant source (see 6.2.6.3)

A Class 2 solution is appropriate where the outcome of the risk assessment deems it necessary that:

— a single failure in a source shall not result in loss of functional capability of the path;

— routine planned maintenance of a source shall not require the load to be shut down.

NOTE Failure of the path can result in unplanned load shutdown and routine maintenance of non-redundant devices can require planned load shutdown.

Where the second source is in the form of an additional supply under local control, the correct capacity specification is critical for the maintenance of services to be protected.

However, the single path between the supply transfer switchgear and the primary distribution equipment represents a single point of failure. In the event of failure or maintenance of that path or the supply transfer switchgear the power distribution has no supply.

c) Class 3: Multiple paths to primary distribution equipment and with redundant sources (see 6.2.6.4)

A Class 3 solution is appropriate where the outcome of the risk assessment deems it necessary that:

— a failure of a functional element shall not result in loss of functional capability;

— planned maintenance shall not require the load to be shut-down.

The provision of an additional path between the supply transfer switchgear and the primary distribution equipment addresses the risk of path failure of Class 2.

However, the failure of a source or path while the other source or path is under maintenance represents a risk. Under such circumstances the power distribution has no supply.

d) Class 4: Multiple paths to primary distribution equipment and with multiple sources (see 6.2.6.5)

A Class 4 solution is appropriate where the outcome of the risk assessment deems it necessary that:

— a failure of a functional element shall not result in loss of functional capability;

— any single event impacting a functional element shall not result in load shut-down;

— planned maintenance shall not require the load to be shut-down.

However, the failure of a path while the other path is under maintenance represents a risk. Under such circumstances the power distribution has no supply. Sources of power supply are fault tolerant during maintenance.

For all Classes, the availability (i.e. continuity of supply) of all supply solutions can be improved by the use of ring loop connection to any primary or secondary supply.

The correct capacity specification of equipment with the power distribution infrastructure (see 6.3.4) is critical for the required level of service for protected, locally protected and short-break connection points. The application of a power supply solution of a given Class does not place requirements on the Class of the power distribution solution.

Class 1: Single source solution

Figure 4 shows a generic implementation of Class 1 supply solution.

An example of a basic single source design solution is a single radial provided from a MV/LV transformer (e.g. 400 V AC).

Transformers can be:

— external to the premises containing the data centre and owned by the utility;

— within the premises, i.e. a functional element of the power supply system of the data centre and can be owned by either the utility, the premises owner or a third party.

Figure 4 — Example of a single path to primary distribution equipment with a single source (Class 1)

Class 2: Redundant source solutions - single path to primary distribution equipment

General

Figure 5 shows the implementation of Figure 4 (see 6.2.6.2) augmented by a second source. This source is an additional supply, dedicated to the needs of the data centre.

Figure 5 — Example of a single path to primary distribution equipment with
a redundant source (Class 2)

Transformers can be:

— external to the premises containing the data centre and owned by the utility;

— within the premises, i.e. a functional element of the power supply system of the data centre and can be owned by either the utility, the premises owner or a third party.

Requirements

Where under control of the premises owner, the location of the pathways and the protection applied to it shall minimize the risk of physical damage.

Recommendations

Where under control of the premises owner, the pathway within the premises carrying the source should be located underground unless the risk from accidental excavation is considered higher than the threat from atmospheric disturbance or deliberate or accidental physical damage.

A connection point should be installed to enable a temporary, redundant, additional supply to be employed during periods when the other is under planned maintenance.

Class 3: Redundant source solutions - multiple paths to primary distribution equipment

General

Figure 6 shows the implementation of Figure 5 (see 6.2.6.3) augmented by a second path to the primary distribution equipment.

If the supply transfer switchgears are interconnected then a main-tie-tie-main configuration shall be employed and;

a) both breakers shall be normally open;

b) for manual operation, the breakers shall be lockable to prevent accidental operations;

c) no automatic procedure shall be applied unless appropriate mitigation of risk is employed;

d) detailed operating instructions shall be provided.

a) Power supply implemented with two primary supplies

b) Power supply implemented with a primary and secondary supply

Figure 6 — Example of multiple paths to primary distribution equipment with a redundant source (Class 3)

Transformers can be:

— external to the premises containing the data centre and owned by the utility;

— within the premises, i.e. a functional element of the power supply system of the data centre and can be owned by either the utility, the premises owner or a third party.

Requirements

Each path shall feed a separate switchgear within the primary distribution equipment.

In such a configuration, the primary and secondary supplies shall:

1) be rated for the maximum load of the entire facility;

2) be active.

Where under control of the premises owner, the location of the pathways and the protection applied to them shall minimize the risk of concurrent physical damage.

If two primary supplies are used as indicated in Figure 6a, then a redundant additional supply shall be installed. Otherwise, the additional supply is a single point of failure in the event of disruption of the primary supply.

If more than one additional supply is required, the connection to the different supply transfer switchgears shall be setup to support the demand of concurrent repair/operate (see EN 50600‑1).

Recommendations

Where under control of the premises owner, the pathways within the premises carrying the source should be:

a) located underground unless the risk from accidental excavation is considered higher than the threat from atmospheric disturbance or deliberate or accidental physical damage;

b) physically separated, between the boundary of the premises and the point of entry into buildings or structures containing the primary distribution equipment, by at least 20 m to ensure that a single incident will not cause damage to both paths and entrance facilities;

c) accommodated within separate fire compartments within any buildings or structures containing the spaces served.

A connection point should be installed to enable a temporary, redundant, additional supply to be employed during periods when the regular feed is under planned maintenance.

Class 4: Multiple source solutions - multiple path to primary distribution equipment

General

Figure 7 shows an example of a multiple source, redundant path solution and which is fault tolerant in which two separate sources (primary and/or secondary supplies) are each supported by an additional supply.

If the supply transfer switchgears are interconnected then a main-tie-tie-main configuration shall be employed and;

a) both breakers shall be normally open;

b) for manual operation, the breakers shall be lockable to prevent accidental operations;

c) no automatic procedure shall be applied unless appropriate mitigation of risk is employed;

d) detailed operating instructions shall be provided.

Figure 7 — Example of a multiple path to primary distribution equipment
with multiple sources (Class 4)

Transformers can be:

— external to the premises containing the data centre and owned by the utility;

— within the premises, i.e. a functional element of the power supply system of the data centre and can be owned by either the utility, the premises owner or a third party.

Requirements

Each path shall feed a separate switchgear within the primary distribution equipment.

In such a configuration, the primary and secondary supplies shall:

a) be rated for the maximum load of the entire facility;

b) be active.

Where under control of the premises owner the pathways within the premises carrying the primary, secondary and additional supplies shall be:

1) located underground unless the risk from accidental excavation is considered higher than the threat from atmospheric disturbance or deliberate or accidental physical damage;

2) physically separated, between the boundary of the premises and the point of entry into buildings or structures containing the primary distribution equipment to ensure that a single incident will not cause damage to both paths and entrance facilities;

3) accommodated within separate fire compartments within any buildings or structures containing the spaces served.

Recommendations

Where under control of the premises owner, the pathways within the premises carrying the primary, secondary and additional supplies should be physically separated, between the boundary of the premises and the point of entry into buildings or structures containing the primary distribution equipment, by at least 20 m.

Sizing

Requirements

The maximum capacity of the power distribution system and the associated spaces of the data centre shall be sized to accommodate:

a) the maximum planned IT load (typically, but not necessarily, based upon the published ‘start up’ power requirements supplied by the equipment manufacturers) taking into account allowance for future growth and technology developments (including increased power density of the ICT equipment);

NOTE Technology developments include technology refresh requirements.

b) the maximum load associated with the environmental control systems serving the data centre spaces taking into account:

— the predicted external ambient temperature and humidity conditions;

— the Availability Class of the environmental control systems;

c) additional loads including, but not restricted to, security, lighting and building/energy controls and also UPS battery recharging following a battery discharge;

d) losses in the power distribution system.

During the planning and dimensioning of the power distribution system and the selection of the functional elements of the power distribution system of the data centre, the following shall also be considered:

e) during construction:

1) temporary/construction power requirements;

f) during operation:

1) initial load (“day one“ of operation);

2) growth of real power load over time;

3) temporary additional loads (taking in account both the load and duration) occurring during technology refresh phases;

4) predicted variations and periodicity of load factor;

g) exceptional conditions (i.e. special and/or unusual loads):

1) type of load;

2) occurrence (i.e. continuous, intermittent, cyclical).

The selection of the functional elements of the power distribution system shall provide a solution which takes into account the variability load.

UPS equipment shall be selected to operate at the variable load taking into account the anticipated/possible power factors of the load.

A network study for the operating modes shall be prepared for the power distribution system. This network study includes at least but not limited to load flow calculation, short-circuit current calculation, protection study.

Recommendations

In some cases when operating high energy switchgear, an arc flash calculation should be provided.

Expansion

Requirements

The selection of the functional elements on the premises accommodating the data centre shall:

a) provide a solution which takes into account the initial IT load and the maximum planned load and maintains optimized efficiency;

b) take into account any need to maintain data centre operation during the introduction of additional capacity.

Recommendations

According to the source paths (single or multiple) UPS systems should be selected and installed to allow their operation at optimum efficiency in accordance with manufacturer’s instructions. Modularity and scalability should be balanced by the number of devices necessary to fulfil availability objectives.

It should be possible to implement the desired stages of expansion without shutting down the critical load or requiring live working.

Requirements

In all cases, the design of the power distribution systems and the selection of its functional elements shall take into account the anticipated power quality of the relevant supply by considering:

a) the active power load;

b) the apparent power load;

c) the requirements for power quality within the data centre;

d) short term inrush current components.

The following scenarios shall be considered when designing the power distribution system associated with UPS:

1) normal operation on UPS fed by utility or by additional supply;

2) load on UPS bypass fed by utility or by additional supply.

Considerations of power quality in relation to UPS shall be in accordance with 6.2.5.4.

The functional elements of the power distribution system shall be selected to meet the demands for selectivity and short-circuit performance in all relevant operational modes and during different phases of scalable deployment.

Recommendations

None.

UPS

Requirements

See 6.2.5.4.1.

Recommendations

See 6.2.5.4.2.

Switchgear

Requirements

LV switchgear and control gear shall be in accordance with the EN IEC 60947 series.

LV switchgear and control gear assemblies shall be in accordance with the EN IEC 61439 series.

HV and MV switchgear shall be in accordance with EN IEC 62271‑200.

Recommendations

HV and MV switchgear should be in accordance with EN IEC 62271‑200:2021,^[9] Category LSC2.

A maintenance-free design should be employed to prevent a shut-down for maintenance on the switchgear.

The switchgear should be free of fluorinated greenhouse gases.

The LV power supply system should be designed with a high form factor according to EN 61439‑6 to reduce maintenance and expansion interruptions by facilitating to de-energize parts of the supply system without the need to de-energize the whole system.

If communication is in place at HV/MV, it should be in accordance with the EN 61850 series, especially when controlling or power quality monitoring is required.

General

The supply at protected connection points shall not be negatively affected by any load steps resulting from switching operations or failures.

The choice of devices and their quality shall be taken into consideration by the planning. Recommendations or installation rules of the suppliers or manufacturers shall be considered during the planning process.

Where power distribution systems incorporate multiple paths, a failure of functional elements in one path shall not negatively affect the provision of power in any other path.

NOTE: Availability Class solutions are not indicated for unprotect connection points.

Four design options of increasing Availability Class are specified for the power distribution infrastructures:

a) Class 1: Single path solution (see 6.3.4.2);

A Class 1 solution is appropriate where the outcome of the risk assessment deems it acceptable that:

— a single failure of a functional element can result in loss of functional capability;

— planned maintenance can require the load to be shut-down.

Protected connection points are fed via a single path. An individual locally-protected connection points reduces the risk associated with a path failure. However, with the increase in the quantity of elements with a local battery supply/UPS the overall number of potential points of failures within the data centre can increase.

Class 1 infrastructures are only appropriate for data centres which can rely on unprotected or short-break connection points.

b) Class 2: Single path solution with redundancy (see 6.3.4.3);

A Class 2 solution is appropriate where the outcome of the risk assessment deems it necessary that:

— a single failure in a device shall not result in loss of functional capability of the path due to redundant devices;

— routine planned maintenance of a redundant device shall not require the load to be shut down.

NOTE Failure of the path can result in unplanned load shutdown and routine maintenance of non-redundant devices can require planned load shutdown.

A failure of the path will result in the failure of supply. An individual locally-protected connection points reduces the risk associated with a path failure. However, with the increase in the quantity of elements with a local battery supply/UPS the overall number of potential points of failures within the data centre can increase.

c) Class 3: Multiple paths providing a concurrent repair/operate solution (see 6.3.4.4);

A Class 3 solution is appropriate where the outcome of the risk assessment deems it necessary that:

— a failure of a functional element shall not result in loss of functional capability;

— planned maintenance shall not require the load to be shut-down.

All paths shall be designed to support the maximum load.

For dual-corded equipment only one path provides a protected connection point and the other path provides a short-break connection point. Supply is not maintained in the event of failure of a device or path while another path is under mainteanance.

NOTE It is not uncommon for Class 3 data centres to be designed with a Class 4 power distribution topology with respect to UPS configuration, resulting in both power distribution paths containing a UPS and both connection points being protected connection points. However, the overall classification of a data centre with such a configuration is still Class 3.

d) Class 4: Multiple paths providing a fault tolerant solution except during maintenance (see 6.3.4.5).

A Class 4 solution is appropriate where the outcome of the risk assessment deems it necessary that:

— a failure of a functional element shall not result in loss of functional capability;

— any single event impacting a functional element shall not result in load shut-down;

— planned maintenance shall not require the load to be shut-down.

All paths shall be designed to support the maximum load.

For dual-corded equipment, protected connection points are provided with two separate paths. Supply is not maintained in the event of failure of a device or path while another path is under maintenance.

Class 1: Single path solutions

General

Figure 8 shows an example of a single path design solution.

Figure 8 — Example of single path power distribution system (Class 1)

Requirements

The UPS or DC power supply shall be designed and installed to provide an adequate supply to allow a controlled shut-down to limit potential damage, caused by an interruption of supply from the primary distribution equipment, to a level consistent with the business impact analysis of EN 50600‑1.

Recommendations

It is recommended to provide a main-tie-tie-main bypass in conjunction with the UPS. The bypass should not be located in the same fire compartment as the UPS.

Class 2: Single path with redundancy solutions

General

Figure 9 shows examples of single path design solutions enhanced by means of redundant devices.

Figure 9 — Example of single path power distribution system with redundancy (Class 2)

Requirements

The UPS or DC power supply shall be designed and installed to provide an adequate supply to limit potential damage, following an interruption of supply from the primary distribution equipment and before the provision of an alternative supply, to a level consistent with the business impact analysis of EN 50600‑1.

Recommendations

It is recommended to provide a main-tie-tie-main bypass in conjunction with the UPS. The bypass should not be located in the same fire compartment as the UPS.

The primary distribution, secondary distribution, UPS and DC supply equipment should be accommodated in separate fire compartments.

At least at the secondary distribution equipment level a connection point (breaker or an empty breaker chassis) to support the maximum load should be implemented to enable concurrent maintenance capability in operation.

Class 3: Multiple paths providing a concurrent and repair operate solution

General

Figure 10 shows an example of a design solution providing multi-path distribution to dual-corded equipment.

Figure 10 — Example of multiple paths providing a concurrent/repair operate solution (Class 3)

Requirements

The UPS or DC power supply shall be designed and installed to provide an adequate supply to limit potential damage, following an interruption of supply from the primary distribution equipment and before the provision of an alternative supply, to a level consistent with the business impact analysis of EN 50600‑1.

If the secondary distribution equipment in the separate paths is interconnected then a main-tie-tie-main configuration shall be employed and;

a) both breakers shall be normally open and locked on each side;

b) only manual operation shall be applied;

c) detailed operating instructions shall be provided.

Recommendations

It is recommended to provide a main-tie-tie-main bypass in conjunction with the UPS. The bypass should be not located into the same fire compartment as the UPS.

The primary distribution, secondary distribution, UPS and DC supply equipment of each path should be accommodated in separate fire compartments.

At least at the secondary distribution equipment level a connection point (breaker or an empty breaker chassis) to support the maximum load should be implemented to enable concurrent maintenance capability in operation.

Class 4: Multiple paths providing a fault tolerant solution except during maintenance

General

Figure 11 shows an example of a multi-path design solution that is fault tolerant (except during maintenance).

Figure 11 — Example of a multiple path, fault tolerant solution except during maintenance (Class 4)

Requirements

The UPS or DC power supply shall be designed and installed to provide an adequate supply to limit potential damage, following an interruption of supply from the primary distribution equipment and before the provision of an alternative supply, to a level consistent with the business impact analysis of EN 50600‑1.

The primary distribution, secondary distribution, UPS and DC supply equipment of each path shall be accommodated in separate fire compartments.

Recommendations

It is recommended to provide a main-tie-tie-main bypass in conjunction with the UPS. The bypass should not be located in the same fire compartment as the UPS.

At least at the secondary distribution equipment level a connection point (breaker or an empty breaker chassis) to support the maximum load should be implemented to enable concurrent maintenance capability in operation.

The feasibility of LV direct current distribution (in the range 380 V DC to 600 V DC) is under consideration by IEC/TC 64. This document will reflect any developments in due course.

A direct current design is possible, whereby the principles of the EN 50600‑2-X series shall be applied accordingly.

Requirements

Equipment shall be installed that is capable of measuring and logging of residual current at the connection between the protective earth and neutral conductors of the power distribution system of the data centre buildings.

Recommendation

A residual current measurement point at the level of the secondary distribution equipment should be considered to be implemented.

Recommendation

Supply

The arrangement of the connection bridge (connection between the protective earth and neutral conductors) is to be selected/specified in consideration of the number/type of sources, the operating conditions and spatial arrangement in a low-voltage installation.

Distribution

When selecting the type of system earthing in low-voltage installations operating currents on the earthing and grounding system should be avoided. Using TN-S type in the power distribution is recommended.

The applied lightning and surge protection measures shall be in accordance with the EN IEC 62305 series and EN 50310, EN 50174‑2 and EN 50174‑3.

The power distribution system and the connected equipment shall be protected by surge protective devices according to EN IEC 62305‑4.

The requirements and recommendations for the segregation of LV power distribution cabling and information technology cabling are provided in EN 50174‑2 for the planner and installer of the information technology cabling.

Data centres shall implement EPO switches taking into consideration national or local regulations and according to the risk analysis of EN 50600‑1.

Where an EPO switch is required, it shall be protected to prevent unintentional operation and to discourage non-emergency use. The minimum protection shall be a cover that shall be lifted before the EPO switch can be operated.

The use of EPO switches should be avoided.

The control system shall be set up in such a way that it complies with the separation and redundancy equal to the Classes for supply and distribution elements. All devices in the system shall operate on a standalone basis, no central control is required. A central control system can be used for monitoring and manual adjustment. If the central control system fails, the components of the system shall operate in a fail-safe mode so that the operation of the data centre is not disrupted. For classes 3 and 4, this can also be achieved with a redundant control system.

For application of quantitative methods to improve aspects of resilience using KPIs, refer to CLC/TS 50600‑4‑31.

For further information for control system see EN ISO 16484‑1, EN ISO 16484‑2, EN ISO 16484‑3 and EN ISO 52120‑1.

Availability of the power supply and distribution system is dependent on the access controls and protection against internal environmental events applied to the functional elements and the interconnecting pathways (see EN 50600‑2‑5).

Protection against external events is also addressed in EN 50600‑2‑5.

Access to the power supply systems shall be limited.

Where under control of the premises owner, equipment comprising the power supply system shall be in areas of Protection Class 3 or above as specified in EN 50600‑2‑5.

Where under control of the data centre premises owner, pathways which are routed in areas of a lower Protection Class shall be monitored for unauthorized access.

Access to the power distribution systems shall be limited.

All equipment comprising the power distribution system shall be in areas of Protection Class 3 or above as specified in EN 50600‑2‑5.

Where pathways are routed in areas of a lower Protection Class they shall be monitored for unauthorized access.

The monitoring of power supply characteristics measured at the locations described in Clause 8 can indicate conditions where availability of supply is under threat from the unauthorized attachment of loads.

Requirements

See 6.2.5.1.1 and 6.2.5.3.1.

Recommendations

See 6.2.5.1.2 and 6.2.5.3.2.

Requirements

Piping systems in spaces containing electrical equipment shall be provided with leakage drainage systems and a leakage monitoring system.

Electrical equipment within a space shall not be located under piping systems (for reasons of leakage or aggregation of condensation), except for the piping systems used for cooling and fire extinguishing systems serving that space.

Recommendations

Leakage monitoring systems should have the ability to identify the physical location of the leakage.

The leakage sensor technology should support multiple detections without the need for replacement.

See 6.2.5.4.2.

No requirements and recommendation in addition to those in 6.5.2.

The hierarchical nature of the power supply and distribution systems provides several key locations indicated by the red arrows in Figure 12 at which to introduce instrumentation that is able to measure the power supply characteristics. The locations where measurement is relevant are defined by the Granularity Level adopted for the data centre to support the energy efficiency enablement objectives of EN 50600‑1, resource and energy management processes of EN 50600‑3‑1 and practices of the Data Center Maturity Model of CLC/TS 50600‑5‑1.

As indicated in Figure 12:

a) Granularity Level 1 provides measurement of power supply characteristics of the primary, secondary and additional supplies (as appropriate) and at the output of the UPS supplying the protected connection points.

b) Granularity Level 2 provides granularity level 1 plus measurement of power supply characteristics at appropriate intermediate points between the primary distribution equipment and the outputs of the final secondary distribution equipment; measurements shall be made at the outputs of the secondary distribution equipment that are the most remote from the primary distribution equipment. Other outputs of the secondary distribution equipment as indicated at point “z” in Figure 12 can be measured as required.

c) Granularity Level 3 provides granularity level 2 and replaced measurements points of protected connection points of secondary distribution equipment with those of the tertiary distribution equipment.

Figure 12 — Possible measurement points

Where a data centre is accommodated within a multi-purpose building, the tertiary distribution equipment should be fed from a dedicated feed from the primary distribution equipment. Where secondary and additional supplies are implemented, the supply transfer switchgear should also be dedicated to the data centre. This will enable segregated energy monitoring for the connected equipment.

During the design phase of the power supply and power distribution system regarding the energy efficiency enablement a calculation shall be performed for the relevant key performance indicators, at least a dPUE calculation (see the EN 50600‑4x series for standard on KPIs relevant to energy use and energy reuse (e.g. PUE, REF, etc.).

The setup of the measurement points shall respect the additional requirements in addition to the EN 50600‑4-x series for standard on KPIs relevant to energy use and energy reuse (e.g. PUE, REF, ERF, etc.).

Also a part of the design phase for the power supply and power distribution system regarding the energy efficiency enablement the requirements of the selected maturity level strategy shall be implemented to support the report of it, the selection process is part of the business and risk analysis at the EN 50600‑1.

The distribution equipment shall be selected to enable measurement of energy use on all phases present.

The equipment used shall provide the following accuracies for the parameters measured:

a) current transformers: EN 61869‑2:2012, Class 1;

with either:

1) measuring instrument equipment: EN IEC 62053‑21:2021, Class 1;

or

2) PMDs of Type II or III according to EN IEC 61557‑12:2022, Class 1 for active energy and active power;

b) PMF of Type II or III according to EN IEC 61557‑12:2022, Class 2 for active energy and active power.

The equipment used should provide the following accuracies for the parameters measured:

a) current transformers: EN 61869‑2:2012, Class 0,5;

with either:

a1) measuring instrument equipment: EN IEC 62053‑22:2021, Class 0,5 S

or

a2) PMDs of Type II or III according to EN IEC 61557‑12:2022, Class 0,5 for active energy and active power;

b) PMF of Type II or III according to EN IEC 61557‑12:2022: Class 1 for active energy and active power.

NOTE 1 a) + a1) or a2) is comparable with b).

NOTE 2 Type II PMDs allow basic power monitoring.

NOTE 3 Type III PMDs allow advanced power monitoring/network performance.

NOTE 4 PMF measurement function dedicated to metering and monitoring electrical parameters within electrical distribution systems embedded in an equipment that is not a PMD and complies to another IEC product standard

A combined measurement for energy consumption and power quality is allowed but the highest requirement regarding different classes is to consider.

Where possible, the measurements should be made at the input to the primary and/or secondary supply transformers and, where relevant, the output of the additional supply (indicated as point “x” in Figure 12).

This will provide the optimum information in relation to energy efficiency objectives. Measurement at point “y” in Figure 12 represents as useful but non-ideal condition.

See 8.3

Where protected connection points, served by tertiary distribution equipment, are installed in a cabinet, frame or rack, which serve different types of loads (e.g. ICT equipment, security or environmental control equipment), Granularity Level 3 shall enable the separate measurement of each type of load.

If embedded measurement equipment (rack mount PDUs) is used an overall accuracy of 3 % for the measurement of the energy consumption based on the maximum rated current of the rack mount PDU shall be provided in accordance with EN 61869‑2.

The cabling infrastructure shall be in accordance with EN 50600‑2‑4.

The used equipment should follow the EN IEC 62053‑22:2021, Class 2 or PDMs or Type II or III in according to EN IEC 61557‑12:2022, Class 2.

Bibliography

CLC/TS 50600‑4‑31, Information technology - Data centre facilities and infrastructures - Part 4-31: Key performance indicators for Resilience

CLC/TS 50600‑5‑1, Information technology - Data centre facilities and infrastructures - Part 5-1: Maturity Model for Energy Management and Environmental Sustainability

EN ISO 52120‑1, Energy performance of buildings - Contribution of building automation, controls and building management - Part 1: General framework and procedures (ISO 52120-1)

EN 50174‑1:2018, Information technology - Cabling installation - Part 1: Installation specification and quality assurance

EN 50600‑2‑1, Information technology - Data centre facilities and infrastructures - Part 2-1: Building construction

EN 50600‑3‑1, Information technology - Data centre facilities and infrastructures - Part 3-1: Management and operational information

EN IEC 62053‑22:2021, Electricity metering equipment - Particular requirements - Part 22: Static meters for AC active energy (classes 0,1S, 0,2S and 0,5S)

IEC 60050‑131:2002, International Electrotechnical Vocabulary — Part 131: Circuit theory

IEC 60050‑691:1973, International Electrotechnical Vocabulary — Part 691: Tariffs for electricity

EN 61439‑6, Low-voltage switchgear and controlgear assemblies - Part 6: Busbar trunking systems (busways)

EN IEC 62271‑200:2021,^[10] High-voltage switchgear and controlgear - Part 200: AC metal-enclosed switchgear and controlgear for rated voltages above 1 kV and up to and including 52 kV

ISO/IEC/TS 8236‑1, Information technology — Provisioning, forecasting and management — Part 1: Data centre IT equipment

ISO/IEC/TS 8236‑2, Information technology — Provisioning, forecasting and management — Part 2: Data centre facility infrastructure

EN ISO 16484‑1, Building automation and control systems (BACS) - Part 1: Project specification and implementation (ISO 16484-1)

EN ISO 16484‑2, Building automation and control systems (BACS) - Part 2: Hardware (ISO 16484-2)

EN ISO 16484‑3, Building automation and control systems – Part 3: Functions

1. As impacted by EN 50160:2022/A1:2025. ↑

2. Some documents of the series are still published as “EN 60947-X”. ↑

3. Some documents of the series are still published as “EN 61439-X”. ↑

4. Some documents of the series are still published as “EN 62040-X”. ↑

5. As impacted by EN 62586-2:2017/A1:2021 and EN 62586-2:2017/AC:2018-09. ↑

6. As impacted by EN 62586-2:2017/A1:2021 and EN 62586-2:2017/AC:2018-09. ↑

7. As impacted by EN 62586-2:2017/A1:2021 and EN 62586-2:2017/AC:2018-09. ↑

8. As impacted by EN IEC 62271-200:2021/A1:2024. ↑

9. As impacted by EN IEC 62271-200:2021/A1:2024. ↑

10. As impacted by EN IEC 62271 200:2021/A1:2024. ↑