Marking and labelling is an important requirement of BS7671. It ensures the maintenance of an electrical installation can be carried out safely and effectively by any competent person.
Each distribution board should have an up to date circuit chart or diagram which indicates the following information; – size and type of protective devices, wiring types and size of conductors and cpc’s, and a description of the connected load. The circuit chart or diagram should also note any circuits vulnerable to an insulation test.
Notices or labels are also required at the following points and equipment within the installation:
- Where an unexpected presence of nominal voltage exceeding 230 V is present
- Where a nominal voltage exceeding 230 V is present between simultaneous accessible equipment
- Where there is a presence of different nominal voltages in the same equipment
- Where a bonding or earthing conductor is connected to equipment
- To identify switchgear or control gear unless there is no possibility of confusion
- To identify protective devices
- To identify isolators and the circuits which they isolate
- Where isolation requires more than one device
- At the origin of the installation a notice showing the next inspection date
- At the origin of the installation a notice for RCD quarterly testing
- At each distribution board a notice warning if there are two wiring colours present