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The construction site and the ground — temporary installations and underground cables

ACS boards, RCD, inspection every 3 months and the rules for cables in the ground

2026-10-06·7 min reading

A construction site installation is always a new installation, even if it only stands for half a year. Here are the rules for responsibility, ACS boards, RCD and inspection — and the Installation Executive Order's measures for cables in the ground: depth, protection, colour and marker tape.

A construction site installation is always new

Construction site installations are always new temporary installations. They must follow the rules that apply when they are set up. In practice, DS/HD 60364-7-704:2018 is followed. Offices, canteens and dormitories on site follow the ordinary rules for installations.

Who is responsible — and who may do what?

  • 01The owner or user of the installation is responsible.
  • 02The authorised installer typically has responsibility up to and including the ACS socket-outlet boards.
  • 03Installations supplied via a plug may be carried out by anyone who can do it safely. So a tradesperson may connect their own plug-supplied board to the ACS board.

The ACS board

The boards on a construction site must be ACS boards according to DS/EN 61439-4. ACS stands for «Assemblies for Construction Sites». Each board's outgoing circuit must have overcurrent and fault protection. The old Danish special rule on loop-through socket-outlets has not been continued.

RCD on the construction site

  • 01All circuits for socket-outlets and hand-held equipment up to and including 32 A must have a 30 mA RCD.
  • 02Above 32 A, the RCD must match the earth resistance. If a 1 A RCD is used, the earth resistance may for example be at most 50 Ω.
  • 03There is no requirement for selectivity between RCDs. If you want it, in practice it requires a ratio of at least 3:1.
  • 04Without a risk assessment, surge protection (SPD) is required.

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