Regulatory framework
The temporary power supply of construction sites is governed by:
- PUE, 7th edition (Chapter 7.1 — electrical installations of buildings; Chapter 6.1 — electric lighting)
- SNiP 12-03-2001 "Occupational safety in construction"
- GOST R 50571.7.704-2013 (requirements for electrical installations on construction sites)
- SP 48.13330.2019 "Organization of construction"
Power supply intake
The temporary connection is arranged through the power supply utility. At the intake point an input distribution unit (VRU) is installed, equipped with:
- An input switch-disconnector or circuit breaker
- An electricity meter
- A residual current device (RCD) at the intake
Distribution panels
Two types of panels are used on a construction site:
VRU (input distribution unit) — the site's main panel. Degree of protection no lower than IP44.
Distribution boards (RP) — intermediate boards for connecting a group of loads. Installed in the work area.
All panels must be fitted with:
- Circuit breakers on each outgoing line
- RCDs with a 30 mA leakage current on all socket groups (PUE clause 7.1.71)
- CEE-type industrial sockets with degree of protection IP44
- A voltage-presence indicator
Mandatory protective devices
- Circuit breakers — on each line, characteristic C or D
- 30 mA RCD — mandatory for all socket groups and portable tools
- 10 mA RCD — for especially hazardous conditions (damp premises, work in excavation pits)
- Circuit breaker at the intake — for overall protection and the ability to shut everything off completely
Earthing
A TN-S or TN-C-S earthing system is mandatory on a construction site. Requirements:
- An earth electrode loop with a resistance of no more than 4 Ω
- All metal equipment enclosures earthed
- Scaffolding and fencing connected to the earthing loop
- Earthing conductor — cross-section of at least 6 mm² (copper) or 10 mm² (aluminium)
Cable runs
- For fixed runs: VVGng-LS cable in protective conduits or trays
- For temporary connections: KG cable (flexible) with rubber insulation
- Routing along the ground: in conduits or at a height of at least 2.5 m above ground level
- Across driveways: in conduits buried to 0.8 m, or at a height of at least 6 m
Portable electrical equipment
- Class II power tools (double insulation) or Class III (42 V) for damp premises
- Extension cords — KG cable 3×1.5 mm² or 3×2.5 mm², no longer than 60 m
- Portable luminaires — voltage no higher than 50 V (PUE clause 6.1.17)
Minimum kit for a construction site
- IP54 input panel with a meter, switch-disconnector and RCD
- 1–2 IP44 distribution boards with circuit breakers and 30 mA RCDs
- VVGng-LS or KG cable for wiring
- Earthing kit (rods, strip, clamps)
- CEE IP44 sockets for connecting equipment
All the electrical equipment you need for a construction site is in our catalogue. We will advise you on selecting a kit.