How to Replace Consumer Units


In the previous edition of PE, we discussed various considerations when replacing a consumer unit (CU) in domestic and similar premises. These included potential pitfalls, the requirements of the Electricity at Work Regulations 1989, the requirements of BS 7671 and industry best practice.

This second article will examine some other issues which need to be considered when replacing a CU.

Pre-work survey

Prior to replacing a CU, the contractor is advised to encourage the customer to have an Electrical Installation Condition Report (EICR) carried out. This is in the interest of both the customer and the installer.

If, for any reason, the customer refuses to have an EICR carried out, then it is recommended that the installer carry out a pre-work survey to find out if there are any immediate or potential dangers or if there is any condition in the existing installation that might cause unwanted tripping of an RCD. The pre-work survey is a precautionary measure in the installer’s own interest.

As part of the pre-work survey, checks need to be made with the customer to see if there are any known defects, faults or damage. The customer must then be advised that power will need to be briefly switched off to allow for the pre-work survey inspection and testing.


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