Installing a distribution board

Choose a flush-mounted or surface-mounted enclosure with a sufficient number of modules and an ingress protection rating (IP) that suits the surroundings. Position the board with clear operating space and access so it can be operated and maintained safely.

Fix the circuit diagram before you install: number of circuits, which loads belong to each, number and type of RCDs and the fuse characteristic (B/C/D). New homes must have at least 2 RCDs of type A with max. 30 mA.

Clip the main switch, RCDs and circuit breakers onto the DIN rail in the planned order. The characteristic is chosen according to the load: B for lighting and sockets, C for motors and many electronic power supplies, D for heavy inrush currents.

Use a busbar (phase comb) to connect the breakers' terminals efficiently rather than loose pieces of wire. Choose the number of poles (1-, 3- or 4-pole) according to the board's layout, and cut the busbar to length so that no bare teeth are left exposed.

Connect the circuits according to the circuit diagram using the harmonised conductor colours (HD 308 S2): protective conductor PE green/yellow, neutral (N) blue, and line (L) brown, black or grey. Tighten all terminals to the specified torque.

Label each circuit so it is clear what it supplies, and place an accurate circuit diagram in or by the board. Unambiguous labelling is a requirement at inspection and makes later fault-finding quick.

Carry out inspection and testing (continuity, insulation resistance, RCD test, polarity, phase sequence) on the board before it is energised. Hand over an up-to-date circuit diagram and verification report at handover.

Take a photo of the finished, labelled board for the documentation — it saves time at the next service visit.