| Full title | Audio/video, information and communication technology equipment. Part 3: Safety aspects for DC power transfer through communication cables and ports |
| Publisher | IEC (TC 108); adopted as EN IEC 62368-3 by CENELEC and as BS EN IEC 62368-3 by BSI |
| Current edition | IEC 62368-3:2017, edition 1.0 |
| UK and EU version | BS EN IEC 62368-3:2020 (current, published 30 April 2020), identical to IEC 62368-3:2017 |
| Used with | IEC 62368-1:2014 (the edition cited in the 2017 text) |
| Related standards | IEC 62368-1, IEEE 802.3, IEC 60364-7-716, ISO/IEC TS 29125 |
What it covers
IEC 62368-3 applies to equipment intended to supply and receive operating power through communication cables or ports. It covers circuits designed to transfer DC power from a power sourcing equipment (PSE) to a powered device (PD).
It is a group safety publication, primarily intended to be used as a product safety standard for the equipment in its scope.
The power transfer uses voltages at energy source class ES1 or ES2, or in very specific cases ES3. The scope gives these examples:
| Energy source class | Examples in the scope |
|---|---|
| ES1 | USB, PoE, ISDN S0 |
| ES2 | Analogue telephone during ringing, ISDN U |
| ES3 | Remote power feeding used by communications service providers and utilities communication circuits, for example RFT circuits such as line powered HDSLx, SHDSLx, VDSLx and G.fast |
Any cable with an industry-standard connector that permits DC power transfer counts as a communication cable, even if no communication takes place. The scope gives a USB cable used only to charge a battery as an example.
Key definitions
- PSE: equipment, other than a dedicated external power supply for specific equipment, that supplies DC power to other equipment through communication cables or ports.
- PD: equipment supplied with DC power by a PSE through communication cables or ports. Some PDs also have a PSE output to pass power on.
- ICT network: a metallically terminated transmission medium with its associated equipment and communication cables, excluding mains used as a communication medium and dedicated HBES/BACS networks.
- The standard notes that IEEE 802.3 uses similar, but different, definitions of PSE and PD.
Structure
| Clause | Content |
|---|---|
| 4 | General requirements |
| 5 | Power transfer using ES1 or ES2 voltages |
| 5.3.1 | DC power transfer interconnection to building wiring |
| 5.3.2 | DC power transfer interconnection to other equipment |
| 5.4 | Safeguards against a single fault condition in the PSE (requirements for the PSE and the PD) |
| 6 | Power transfer using RFT (remote feeding), including energy source limits, safeguards, installation instructions and fire protection |
| Annex A | Remote power feeding (informative) |
| Annex B | Rationale for 5.4 (informative) |
The standard is used together with IEC 62368-1. Where a requirement refers to a criterion in Part 1, the Part 1 reference is given.
The energy source limits
The energy source classes come from IEC 62368-1. In outline:
- The standard notes that ES1 has similar limits to non-hazardous voltage definitions in other standards, for example SELV and PELV.
- ES2 has single-fault limits generally similar to non-hazardous voltage definitions in other standards.
- PS2 circuits are generally expected to deliver less than 100 W to an undefined load, in normal and single fault conditions.
For exact limits, use the classification tables in IEC 62368-1.
How it relates to other documents
| Document | Relationship |
|---|---|
| IEEE 802.3 (802.3af, at, bt) | Defines the PoE system and power classes. IEC 62368-3 covers the product safety of PSE and PD equipment. See the IEEE 802.3bt page |
| IEC 60364-7-716:2023 | Installation rules for ELV DC power over ICT cabling. Its scope covers power sourcing equipment in accordance with IEC 62368-3 |
| ISO/IEC TS 29125 | Guidance on cable bundle temperature rise for remote powering. See the ISO/IEC TS 29125 page |
| BS 7671 Section 716 | UK installation rules for ELV DC power over ICT cable |
What it means in practice
- Ask for PSE equipment, such as PoE switches and midspans, to be assessed to IEC 62368-1 together with IEC 62368-3.
- For cable choice, bundle sizes and temperature rise, see the installation standards (IEC 60364-7-716 / BS 7671 Section 716) and ISO/IEC TS 29125.
- The 2017 edition is written against IEC 62368-1:2014. IEC 62368-1 is now at edition 4.0 (2023), so check which edition of Part 1 a test report uses.
Related reading: BS 7671 Amendment 4: the new PoE and ICT earthing rules · PoE types: what you need to know.