Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
PD IEC TS 62735 — Direct Current (DC) Plugs and Socket-Outlets for ICT Equipment Technical Specification Series (2,6 kW and 5,2 kW Systems)
DC Plugs and Socket-Outlets for ICT Equipment Installed in Data Centres and Telecom Central Offices — 2,6 kW and 5,2 kW Systems (2015/2016 Editions)
🔋 PD IEC TS 62735 is the BSI-adopted IEC/TS 62735 series for direct current (DC) plugs and socket-outlets for information and communication technology (ICT) equipment installed in data centres and telecom central offices. The two parts in this batch are Part 1, which specifies the 2,6 kW plug and socket-outlet system, and Part 2, which specifies the 5,2 kW system. Both are handled by BSI Technical Committee PEL/23 (Electrical accessories). As high-voltage DC (HVDC, e.g., 400 V DC) power distribution gains ground in data centres and telecom offices, standardised, safely hot-pluggable DC connectors have become essential; this series provides unified ratings, safety, and construction requirements for DC plugs and socket-outlets used with ICT equipment.
💡 Traditional data centres use 48 V DC or AC power; the new generation of 400 V DC (HVDC) distribution reduces conversion stages, improves efficiency, and allows batteries to be directly connected. At high DC voltage, arc extinction, shock protection, and thermal management requirements far exceed those of low-voltage DC accessories, which is why a dedicated series is needed.
1. Series Composition and System Overview 📌
| Standard | Title | IEC Edition | Core Content |
|---|---|---|---|
| PD IEC/TS 62735-1:2015 | DC plugs and socket-outlets for ICT equipment installed in data centres and telecom central offices — Part 1: Plug and socket-outlet system for 2,6 kW | IEC TS 62735-1 (Ed.1.0, 2015-08) | Ratings, classification, marking, dimensions, shock protection, terminals, construction, interlocking |
| PD IEC/TS 62735-2:2016 | DC plugs and socket-outlets for 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 (Ed.1.0, 2016-12) | Same clause structure as Part 1, higher power rating with hot-plug requirements |
⚠️ This series addresses DC power distribution for ICT equipment in data centres and telecom central offices; general industrial or household low-voltage DC plugs and socket-outlets are not covered here and should follow other relevant standards. Always verify the rated power and voltage level when selecting.
2. Common Construction and Safety Requirements 🔧
Both documents follow the mature clause structure of IEC 60884-1 (plugs and socket-outlets for household and similar purposes) with extensions for high DC voltage characteristics:
- General requirements and notes on tests: overall requirements, test conditions, and sample quantities.
- Ratings: voltage, current, and power ratings of plugs and socket-outlets.
- Classification: by method of cable connection, terminal type, degree of protection against electric shock, presence of shutters, and method of application/mounting.
- Marking: polarity, ratings, and other markings to prevent DC polarity reversal.
- Checking of dimensions: interchangeability across manufacturers.
- Protection against electric shock: construction requirements under high DC voltage.
- Provision for earthing: earthing terminals and continuity where required.
- Terminals and terminations: terminal types, connection reliability, and temperature rise.
- Construction of socket-outlets and plugs: housing, insulation, insertion/withdrawal force, and mechanical strength.
- Interlocked plug and socket-outlet systems: interlocks for situations involving possible disconnection under voltage, ensuring break-before-pull and arc prevention.
3. Differences Between the 2,6 kW and 5,2 kW Systems 📊
Part 2 follows the same structural framework as Part 1 but reinforces the higher power level (5,2 kW):
- Higher current-carrying capacity: contact size, terminal cross-section, and heat dissipation are increased to keep temperature rise within limits.
- Hot-plug capability: arc energy at higher power is greater, placing stricter demands on insertion order, contact design, and arc extinction.
- Interlock and sequenced operation: the 5,2 kW system emphasises first making earth/signal then power, or using interlocks to prevent live operation.
🚨 DC arcs have no natural zero crossing: once disconnected under load, the arc can burn continuously, far more dangerous than AC. The interlock and sequenced insertion requirements of this series are key to safety, and maintenance staff must strictly follow “disconnect first, then plug/unplug”.
4. Summary of Key Technical Requirements 🔧
| Topic | Key Requirement | Document |
|---|---|---|
| Ratings | 2,6 kW / 5,2 kW power levels with corresponding current ratings | 62735-1 / -2 |
| Classification | Connection, terminal, protection, shutter, mounting classification | 62735-1 / -2 |
| Shock protection | Shock-protection construction under high DC voltage | 62735-1 / -2 |
| Terminals and temperature rise | Reliable terminations within temperature-rise limits | 62735-1 / -2 |
| Construction strength | Housing, insulation, insertion force, mechanical strength | 62735-1 / -2 |
| Interlocking | Live-disconnect protection, break-before-pull | 62735-1 / -2 |
5. Engineering Practice 🛠️
- 🔍 400 V HVDC data centre distribution: use this series’ plugs and socket-outlets to connect server power supplies for standardised, hot-pluggable DC distribution.
- 🔧 Rack deployment and scaling: wire racks with standard connectors to reduce custom cabling, speeding deployment and improving maintainability.
- 📊 Polarity error prevention: use standard marking and keyed structures to reduce device damage from DC polarity reversal.
- 📋 Operational safety: encode interlock and de-energise-before-unplug requirements into O&M procedures and train personnel to avoid live connection/disconnection.
6. Frequently Asked Questions ❓
❓ Q: Why do data centres need a DC plug-and-socket standard?
A: As 400 V DC (HVDC) spreads in data centres, ICT equipment needs standardised DC connectors. A unified standard ensures interchangeability, safety, and hot-plug capability across manufacturers, supporting large-scale, high-efficiency deployment.
A: As 400 V DC (HVDC) spreads in data centres, ICT equipment needs standardised DC connectors. A unified standard ensures interchangeability, safety, and hot-plug capability across manufacturers, supporting large-scale, high-efficiency deployment.
❓ Q: How big is the difference between the 2,6 kW and 5,2 kW systems?
A: They share the same clause system and safety framework; the difference lies mainly in current-carrying capacity, contact size, heat dissipation, and hot-plug arc control driven by the power level. Choose based on per-rack or per-device power and distribution architecture.
A: They share the same clause system and safety framework; the difference lies mainly in current-carrying capacity, contact size, heat dissipation, and hot-plug arc control driven by the power level. Choose based on per-rack or per-device power and distribution architecture.
❓ Q: Why is a DC arc more dangerous than an AC arc?
A: AC current crosses zero each cycle, giving the arc a chance to extinguish; DC has no zero crossing, so the arc can burn continuously with high energy and temperature. DC plugs and socket-outlets must therefore use interlocks, contact design, and operating sequences to prevent live disconnection.
A: AC current crosses zero each cycle, giving the arc a chance to extinguish; DC has no zero crossing, so the arc can burn continuously with high energy and temperature. DC plugs and socket-outlets must therefore use interlocks, contact design, and operating sequences to prevent live disconnection.
🔍 Q: What is the purpose of shutters?
A: Shutters cover the live socket contacts when no plug is inserted, preventing foreign objects or fingers from touching live parts — an important structural measure that raises the degree of shock protection. The series classifies socket-outlets by shock protection; shutters are one optional classification attribute.
A: Shutters cover the live socket contacts when no plug is inserted, preventing foreign objects or fingers from touching live parts — an important structural measure that raises the degree of shock protection. The series classifies socket-outlets by shock protection; shutters are one optional classification attribute.