Clause-by-clause translation of the Chinese standard GB 50054-2011: selection of apparatus and conductors, protection against electric shock, circuit protection, cable installation. All key clauses with numbers.
| Document | GB 50054-2011 Code for design of low-voltage electrical installations |
| Edition | 2011 |
| Status | Current (mandatory, GB) |
| Issued by | Ministry of Housing and Urban-Rural Development of China (MOHURD) |
| Applies to | Design of low-voltage AC 50 Hz installations up to 1000 V in new, renovated and expanded buildings |
| № | Chapter / section |
|---|---|
| 1 | General provisions |
| 2 | Terms |
| 3 | Selection of apparatus and conductors |
| 4 | Arrangement of distribution equipment |
| 5 | Protection against electric shock |
| 6 | Protection of distribution circuits |
| 7 | Wiring of distribution circuits |
| A | Annex A — k factors |
GB 50054-2011 (低压配电设计规范) came into force on 1 June 2012, replacing GB 50054-95. It applies to AC 50 Hz installations up to 1000 V. The document has 7 chapters and 1 annex. Seven clauses are mandatory: 3.1.4, 3.1.7, 3.1.10, 3.1.12, 3.2.13, 4.2.6, 7.4.1.
3.1.1 Apparatus must suit the environment, frequency, voltage; rated current ≥ calculated current; withstand dynamic and thermal short-circuit stresses; have adequate breaking capacity.
3.1.3 Isolating devices (all poles) for maintenance and testing; anti-mistake provisions where wrong operation is dangerous.
3.1.4 (mandatory) In TN-C systems the PEN conductor must not be disconnected; PEN must not be connected through switching apparatus.
3.1.7 (mandatory) Semiconductor devices must not be used as isolating devices.
3.1.8–3.1.10 Every controlled part needs a functional switching device; isolators, fuses and connector strips must not serve as functional switches (3.1.10 mandatory).
3.1.11 RCD selection: must open all live conductors (except TN-S with reliably earthed neutral); rated non-tripping current must exceed expected leakage; type per GB/Z 6829.
3.1.12 (mandatory) When an RCD is used for indirect-contact protection, a protective conductor is mandatory.
3.1.13 In TT systems a single RCD protecting the whole installation must be at the intake (unless Class II equipment).
3.1.14 In IT systems the RCD non-tripping current ≥ first earth-fault current.
3.1.17 IT systems require continuous insulation monitoring (250/500/1000 V test voltage, 0.5/0.5/1.0 MΩ setpoints).
3.2.2 Cross-section: ampacity ≥ calculated current; protection coordination; thermal/dynamic stability; voltage drop; mechanical strength. Minimum fixed copper sections: 1.5 mm² in conduit/trunking; bare on insulators — copper 10 mm², aluminium 16 mm².
3.2.3 Max insulation temperatures: PVC 70 °C, XLPE/EPR 90 °C, MI 105 °C (inaccessible) / 70 °C.
3.2.7 Neutral sized as phase when phase ≤ 16 mm² copper / ≤ 25 mm² aluminium, and in all single-phase two-wire circuits.
3.2.10 Minimum PEN: copper 10 mm², aluminium 16 mm².
3.2.12 PEN split: separate PE and N terminals/busbars; PEN first to the PE busbar; N must not bond to other earthed parts.
3.2.13 (mandatory) Extraneous conductive parts must not be used as PEN.
3.2.14 PE sizing: ≤16 mm² — same as phase; 16–35 mm² — 16 mm²; >35 mm² — half of phase. Separate PE: copper 2.5 mm² (protected) / 4 mm² (unprotected); equipment leakage >10 mA — 10 mm² copper.
3.2.15–3.2.17 Equipotential bonding: main — copper 6–25 mm²; supplementary/local — ≥ half of the largest PE in the zone, max 25 mm².
4.2.1 Floor panels raised ≥50 mm indoors, ≥200 mm outdoors; sealed bases against rodents.
4.2.6 (mandatory) Bare live parts over walkways ≥ 2.5 m; below — barriers IP2X with bottom edge ≥2.2 m.
4.3.2 Rooms over 7 m long need two exits; doors open outward.
4.3.7 Openings protected with IP3X mesh against rodents.
5.1.2 Accessible bare live parts above 25 V must be enclosed to IP2X (IPXXB).
5.1.12 RCD ≤ 30 mA as additional protection against direct contact.
5.2.4 Main equipotential bonding in every building: PE/PEN, earthing terminal, metal water/gas pipes, building steelwork.
5.2.8–5.2.9 TN disconnection: 0.4 s at 220 V, 0.2 s at 380 V; fixed equipment — 5 s max.
5.2.13 If a breaker cannot meet TN times — use an RCD.
5.2.15 TT: RA × Ia ≤ 50 V.
5.2.19–5.2.24 IT: first fault — alarm (no disconnection); insulation monitoring mandatory; second fault — disconnect in 0.4–0.8 s; IT should not distribute N.
5.3.2 SELV/PELV ≤ 50 V AC.
5.3.11 SELV plugs/sockets incompatible with other systems, no PE contact.
6.1.1 Every distribution circuit needs short-circuit and overload protection.
6.2.4 For breakers, fault current at the line end ≥ 1.3 × instantaneous/short-delay trip setting.
6.2.5 SC protection at circuit start and at conductor-size reductions; max 3 m unprotected run.
6.3.3 Overload: IB ≤ In ≤ Iz and I2 ≤ 1.45 × Iz.
6.4.3 Fire-protection RCD: ≥ 300 mA, opens all live conductors.
7.1.3 Max 8 wires in one conduit (multiple lighting circuits).
7.2.1 Direct wiring: sheathed cable ≤ 6 mm²; heights 2.5/1.8 m; no embedding in plaster.
7.2.8 Attics with combustibles: metal conduit/trunking only.
7.2.9 All conductors of a circuit in the same conduit/trunking.
7.2.11 Clearances to hot pipes: 0.2/0.3 m (DHW below/above), 0.5/1.0 m (steam).
7.2.14 Conduit/trunking fill ≤ 40%, ≤ 30 conductors.
7.4.1 (mandatory) Bare conductors ≥ 3.5 m (2.5 m with IP2X mesh barrier).
7.6.12 Conduit ID ≥ 1.5 × cable OD.
7.6.14 Tray fill: power 40%, control 50%.
7.6.35–7.6.36 Underground: ≤ 6 cables per route; depth ≥ 700 mm (1 m farmland); 100 mm sand bed; protection plates.
7.6.52–7.6.57 MI cables: bending radius 2D–6D; S/Ω loops at thermal expansion and settlement joints.
7.7.5 Electrical shafts: 1-hour fire rating; service doors to corridors; floor sealing.
7.7.6 HV/LV/emergency circuits in one shaft: ≥ 300 mm spacing or barriers.
For designers familiar with PUE or IEC 60364, GB 50054-2011 is conceptually close: 30 mA RCDs, TN-C-S, equipotential bonding, selectivity. Key differences: 220/380 V, GB 1002 sockets (flat pins), 1.5 mm² minimum fixed copper, fire RCD 300 mA, PEN must not pass through switching devices (as in PUE 1.7.133).
Automatic single-line diagrams, PUE/GOST/IEC calculations, specification and PDF — from one model.
Start freeData is for reference. Final design decisions must follow current regulations and a qualified engineer.
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