IEC TS 62735-2:2016

Direct current (DC) plugs and socket-outlets for information and communication technology (ICT) equipment installed in data centres and telecom central offices - Part 2: Plug and socket-outlet system for 5,2 kW

IEC TS 62735-2: 2016(E) applies to plugs and fixed socket-outlets for class I equipment with two active contacts plus an earthing contact, a rated power of 5,2 kW and a rated voltage range from 294 V to 400 V d.c. They are intended to power d.c. information and communication technology equipment only. The 2,6 kW system complying with Part 1 is safely compatible with the system complying with this part as it is possible to insert the 2,6 kW plug in the 5,2 kW socket-outlet but it is not possible to insert the 5,2 kW plug into the 2,6 kW socket-outlet.
This publication is to be read in conjunction with IEC TS 62735-1:2015

General Information

• Status: Published
• Publication Date: 13-Dec-2016
• ICS: 29.120.01 - Electrical accessories in general
• ICS: 29.120.30 - Plugs, socket-outlets, couplers
• Technical Committee: TC 23 - Electrical accessories
• Drafting Committee: WG 19 - TC 23/SC 23B/WG 19
• Current Stage: PPUB - Publication issued
• Start Date: 14-Dec-2016
• Completion Date: 06-Jan-2017

Overview

IEC TS 62735-2:2016 is a technical specification developed by the International Electrotechnical Commission (IEC) that defines the requirements for direct current (DC) plugs and fixed socket-outlets specifically designed for information and communication technology (ICT) equipment installed in data centres and telecom central offices. This standard covers plugs and socket-outlets for class I equipment with two active contacts plus an earthing contact, supporting a rated power of 5.2 kW and a voltage range from 294 V to 400 V DC. Its primary objective is to ensure safe, reliable power connections for DC-powered ICT equipment in high-demand environments, promoting compatibility, safety, and efficiency.

Key Topics

• Rated Power and Voltage
  The standard specifies plugs and socket-outlets with a rated power of 5.2 kW and a rated voltage range of 294 V to 400 V DC, directly supporting high-performance ICT equipment.

• Compatibility
  Backwards compatibility is ensured: a 2.6 kW plug compliant with IEC TS 62735-1 can be used with a 5.2 kW socket-outlet as specified in Part 2. However, the higher-powered 5.2 kW plug cannot be used with a 2.6 kW socket-outlet, preventing unsafe electrical connections.

• Safety Features

  • Earthing Contact: For enhanced protection against electric shock.
  • Interlock Systems: Mandates either automatic or mechanical interlock mechanisms to prevent arcing during connection/disconnection.
  • Protection and Testing: Specifies requirements for temperature rise, breaking capacity, mechanical strength, resistance to heat, and markings.
  • Markings: Guidelines for “ON”/“OFF” denotation and visibility near switches.

• Physical and Mechanical Compliance

  • Standardized dimensions and gauges ensure reliable fit and secure engagement.
  • Requirements for terminals, conductor sizes, and pull/torque test values for secure cable connections.

Applications

IEC TS 62735-2:2016 is directly applicable to:

• Data Centres:
  Ensures reliable and safe DC power delivery to servers, switches, storage devices, and related ICT infrastructure, critical for uninterrupted operation, high efficiency, and energy savings.

• Telecommunications Central Offices:
  Supports robust DC power connections for telecom equipment, helping maintain network uptime and performance.

• OEMs and Equipment Suppliers:
  Offers manufacturers a clear, internationally recognized specification for designing, testing, and supplying compliant plugs and socket-outlets for the global ICT market.

• System Integrators and Facility Managers:
  Guides selection and installation of DC power distribution components, supporting best practices in safety and system compatibility within large-scale ICT environments.

Related Standards

• IEC TS 62735-1:2015
  Part 1 of the series addresses the 2.6 kW DC plug and socket-outlet system, offering foundational compatibility information.

• IEC 60999-1
  Provides safety requirements for electrical copper conductors and clamping units, relevant for screw-type and screwless DC plug/socket designs.

Practical Value

Implementing IEC TS 62735-2:2016 supports:

• Enhanced Safety: Through robust earthing provisions, interlocks, and rigorous testing protocols.
• International Compliance: Eases global deployment and procurement of DC-powered ICT infrastructure.
• System Reliability: Reduces risk of mismatched connections and equipment failure.
• Future-Proofing: Aligns with the industry trend toward higher voltage DC distribution in next-generation data centres and telecom hubs.

By adhering to IEC TS 62735-2:2016, stakeholders in the ICT and telecom sectors can ensure safer, more efficient, and internationally compatible DC power delivery systems for critical infrastructure.

Standards Content (Sample)

IEC TS 62735-2 ®
Edition 1.0 2016-12
TECHNICAL
SPECIFICATION
Direct current (DC) plugs and socket-outlets for information and communication
technology (ICT) equipment installed in data centres and telecom central
offices –
Part 2: Plug and socket-outlet system for 5,2 kW
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IEC TS 62735-2 ®
Edition 1.0 2016-12
TECHNICAL
SPECIFICATION
Direct current (DC) plugs and socket-outlets for information and communication

technology (ICT) equipment installed in data centres and telecom central

offices –
Part 2: Plug and socket-outlet system for 5,2 kW

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.120.01; 29.120.30 ISBN 978-2-8322-3708-3

– 2 – IEC TS 62735-2:2016 © IEC 2016
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General requirements . 7
5 General notes on tests . 7
6 Ratings . 7
7 Classification . 7
8 Marking . 7
9 Checking of dimensions . 8
10 Protection against electric shock . 8
11 Provision for earthing . 8
12 Terminals and terminations . 8
13 Construction of socket-outlets . 11
14 Construction of plugs . 11
15 Interlocked plug and socket-outlet systems . 12
16 Resistance to ageing, protection provided by enclosures, and resistance to
humidity . 12
17 Insulation resistance and electric strength . 12
18 Operation of earthing contacts . 13
19 Temperature rise . 13
20 Breaking capacity . 14
21 Normal operation . 14
22 Force necessary to withdraw the plug . 14
23 Flexible cables and their connection . 15
24 Mechanical strength . 16
25 Resistance to heat . 16
26 Screws, current-carrying parts and connections . 16
27 Creepage distances, clearances and distances through sealing compound . 16
28 Resistance of insulating material to abnormal heat and to fire . 16
29 Resistance to rusting . 16
Annexes . 16
Annex AA (normative) Standard sheets and gauges . 17
Bibliography . 21

Figure AA.1 – Standard sheet 4: 5,2 kW / 294 V to 400 V d.c. socket-outlet for class I
equipment . 18
Figure AA.2 – Standard sheet 5: 5,2 kW / 294 V to 400 V d.c. plug for class I
equipment . 19
Figure AA.3 – Standard sheet 6: positioning of the “+” and “−” pins/socket-contacts . 20

Table 1 – Relationship between rated power and connectable nominal cross-sectional

areas or American Wire Gauge (AWG) size of copper conductors . 9

Table 2 – Values for pull test for screw-type terminals . 9
Table 3 – Composition of conductors for plugs . 9
Table 5 – Relationship between rated power and connectable cross-sectional areas or
AWG size of copper conductors for screwless terminals . 10
Table 6 – Value for pull test for screwless-type terminals . 10
Table 7 – Values for flexing under mechanical load test for copper conductors . 10
Table 8 – Test current for the verification of electrical and thermal stresses in normal
use for screwless terminals . 10
Table 9 – Nominal cross-sectional areas or AWG size of rigid copper conductors for
deflection test of screwless terminals . 11
Table 10 – Deflection test forces . 11
Table 14 – External cable dimension limits for surface-type socket-outlets . 11
Table 15 – Nominal cross-sectional areas of copper conductors and test currents for
the temperature rise test . 13
Table 16 – Maximum and minimum withdrawal force for plugs and socket-outlets . 15
Table 17 – External dimensions of flexible cables to be accommodated by cord
anchorages . 15
Table 18 – Torque test values for cord anchorages . 15
Table 19 – Maximum dimensions of flexible cables to be accommodated in rewirable
accessories . 16

– 4 – IEC TS 62735-2:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DIRECT CURRENT (DC) PLUGS AND SOCKET-OUTLETS FOR
INFORMATION AND COMMUNICATION TECHNOLOGY (ICT) EQUIPMENT
INSTALLED IN DATA CENTRES AND TELECOM CENTRAL OFFICES –

Part 2: Plug and socket-outlet system for 5,2 kW

FOREWORD
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Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 62735-2, which is a technical specification, has been prepared by IEC technical
committee 23: Electrical accessories.

This technical specification is to be used in conjunction with IEC 62735-1:2015.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
23/743/DTS 23/745A/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
This Part 2 supplements or modifies the corresponding clauses in IEC 62735-1 so as to
convert that publication into the IEC technical specification: Direct current (DC) plugs and
socket-outlets for information and communication technology (ICT) equipment installed in data
centres and telecom central offices.
Where this Part 2 states "addition", "modification" or "replacement", the relevant requirement,
test specification or explanatory matter in Part 1 should be adapted accordingly.
Where no change is necessary, this Part 2 indicates that the relevant clause or subclause
applies.
In this publication:
1) The following print types are used:
– Requirements proper: in roman type.
– Test specifications: in italic type.
2) Subclauses, notes, tables or figures which are additional to those in Part 1 are numbered
starting from 101 and additional list items are numbered from aa). Additional annexes are
lettered AA, BB, etc.
A list of all parts in the IEC 62735 series, published under the general title Direct current (DC)
plugs and socket-outlets for information and communication technology (ICT) equipment
installed in data centres and telecom central offices, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 6 – IEC TS 62735-2:2016 © IEC 2016
DIRECT CURRENT (DC) PLUGS AND SOCKET-OUTLETS FOR
INFORMATION AND COMMUNICATION TECHNOLOGY (ICT) EQUIPMENT
INSTALLED IN DATA CENTRES AND TELECOM CENTRAL OFFICES –

Part 2: Plug and socket-outlet system for 5,2 kW

1 Scope
This clause of Part 1 is applicable except as follows:
Replacement:
Replace the first paragraph with the following:
This part of IEC 62735, which is a technical specification, applies to plugs and fixed socket-
outlets for class I equipment with two active contacts plus an earthing contact, a rated power
of 5,2 kW and a rated voltage range from 294 V to 400 V d.c. They are intended to power d.c.
information and communication technology equipment only.
The 2,6 kW system complying with Part 1 is safely compatible with the system complying with
this part as it is possible to insert the 2,6 kW plug in the 5,2 kW socket-outlet but it is not
possible to in
...