This country is awash with documentation. We should strive to reduce that burden where possible. Like for like replacement seems like one of those areas that doesn’t need paperwork unless something needs to be communicated to the client. It would seem reasonable that the responsibility for the safety of such work should be left squarely with the person doing the replacing, who, in my view, should be a competent electrician. A competent electrician would not replace a socket if there was no earth or fit a replacement class 1 luminaire to a circuit with no cpc. Lack of RCD or protective bonding etc will require a judgement call and in such cases recording that communication might be prudent. A competent electrician should also be able to determine the amount of testing that might be necessary and should note the results in their own day to day job records in much the same way as time and materials would be recorded. 

I have a NAPIT Dangerous Situation Report Pad under the seat in my van, I rarely write one out, but do if needs I do.

The last one I wrote out was around three months ago, I went to alter an electric shower circuit and connect a replacement shower, whilst I was working in the airing cupboard I saw that there was an insecure immersion heater cap and another was missing completely as well as the wiring being in very poor condition.

So I wrote out a Minor Works Certificate for the work on the shower circuit and a Dangerous Situation Report to advise the customer about the dangerous immersion heaters, getting her to countersign it.

You cannot possibly fix everything you find that needs fixing whilst you are working, at some point you have got to be realistic and make sure the customer is aware of issues and potential dangers then leave.

I think that in anatomical terms, that is known as covering your derrière.

I am interested to know about the format of these reports, and well done for getting the customer to acknowledge receipt.

One of my tutors suggested using NCR paper. More modern might be to photograph the report. Even more modern might be to use an app which produces the report and saves a copy. Even more modern still would be to save a copy to your NAPIT (other CPS schemes exist, or at least bother does) account.

A local company prints NCR copy sets for me, actually they were the only printers who knew what they were when I ask a few for quotes.

One printer actually emailed me a quote for “NCR pads including two sheets of carbon paper per pad”.

The printer who does the NCR (No Carbon Required) pads for me explained that digital printers can’t actually do NCR pads if you want reverse printing on the top sheet, because the paper is too thin and when you print one side you cannot then put the paper back through the printer to print the reverse.

Being traditional printers they have made some aluminium type sheets to print my NCR pads, making the first set of pads expensive, but easy to reorder at a lower cost.

Thanks for all the answers.

If you replace a light switch in an existing installation you may not actually do any testing and just write the the Minor Works Certificate out recommending upgrades and improvements.

An insulation test may not be reasonable or practical, there may not be a circuit protective conductor or RCD to test.

Even if there is a circuit protective conductor and RCD it’s only a loop test and just one RCD test, pressing the button twice on a tester is hardly over demanding.

OK thanks, I assumed that issuing a MEIWC for 'like for like' would require performing all tests listed, including Ze and disconnecting bonding cables to test with long leads. I'm still not sure what would be required. I usually check Zs and polarity. Which tests would you perform and would you mark the rest as LIM?

Hypothetically, what if you tested IR when replacing a light switch and it failed, less that 1M ohm. Would it need to be rectified or only noted down in the comments as it's only replacement and not 'new work'? - same as a missing CPC on lights or no bonding or RCD protection.

I think you have failed to realise the use of a MWC. Minor works are basically maintenance, changing something because it has failed, is damaged etc. Fitting a new class one fitting to an unsuitable circuit does not get an MWC because you can't do it, you will have to add the earthing conductor, or possibly an isolating transformer and that gets an EIC. The testing part would usually simply be functional unless a problem is seen, and in this case an EICR is the correct form, although you may well not examine the whole installation, particularly if it is a large factory or hospital.

The "like for like" idea is simply to point out that the MWC is really just to ensure continuity of documentation, so that one can record what has been done. Many electricians "forget" to do them for minor jobs, and certainly most domestic customers don't care. I assume you are asking because you are studying, the correct answer is my second sentence, reality is that one finds remarkably few with installation documentation. A large factory with a maintenance electrician should have several (10 maybe) a week, one for every mains voltage job he does, and exactly following BS7671 for every job with wiring whatever voltage that is part of the fixed wiring.

MEIWCs can be used for altering an existing circuit, for example adding a new socket in a bedroom. In that case all tests need to be performed on the MEIWC and the work needs to meet the latest BS7671. This may mean, for example, rectifying faults on the existing circuit or adding RCD protection and bonding.

I think it's been established that a 'like for like' replacement would not require the existing circuit to meet the latest BS7671 (commonly missing RCD, bonding, light CPC etc.), but should not make the installation any less safe and some professional common sense used.

What I'm now asking is if a MEIWC is used to document a 'like for like' replacement, a light switch for example, what tests would be required? And what happens if they fail? 

A failed test on an existing circuit where new work has been added would need rectifying for the new work to comply. But is this not the case for 'like for like'? If we accept that the circuit has no CPC or RCD but we are making it no worse, do we do the same for a failed IR test, or is the test not needed.

Testing IR, continuity, Ze and long leading bonding cables adds time and cost to the client, and if it uncovers failed tests then this adds more.