Insulation Resistance testing, on additions & alterartions

[Midwest]

I had a job today relocating the electrical supply for a power shower in a ensuite bathroom, to the airing cupboard where the new shower pump is now located. The FCU for the supply was already located in the airing cupboard, so the existing cable was long enough, I just added a flex outlet plate to connect up the new shower pump. I carried out the normal dead tests/live tests, but I was unable to successfully carry out the IR tests, as the FCU has been previously fed via another FCU/RCD. This feeds another shower pump in the main bathroom, which eventually will be removed. When I return to remove the old bathroom supply, and probably the FCU/RCD (the CU has a RCD main switch), I will retest the IR.

However, this has got me thinking. In the past, for smaller jobs, replacing luminaires or replacing an odd socket, I haven't carried out any tests, other than perhaps to do Zs or RCD test. Having subbied for other sparks/companies, I've not been asked to provide any test results, for some alterations & additions. I know what the regs says, but I just wonder what others do, in terms of tests. Now am I doing too much or too little, for example, the installation I gave in my first paragraph, or other examples you wish to describe.

 

[westward10]

You would have to fill out a MWC, one of the required tests is IR. I always test the entire circuit but also test before any alterations to highlight any possible existing faults. Why couldn't you carry out IR test, because of the rcd/fcu. I take them out of circuit.

 

[Pete999]

What Westy said

 

[Midwest]

You would have to fill out a MWC, one of the required tests is IR. I always test the entire circuit but also test before any alterations to highlight any possible existing faults. Why couldn't you carry out IR test, because of the rcd/fcu. I take them out of circuit.

Yep the existing FCU/RCD is currently powering the bathroom shower, which is the only facility the client has. Once the ensuite is done, the bathroom will be refurbished, then I'll remove the FCU/RCD and retest my altered circuit. Could of removed it now, but didn't want to waste my time testing something, that's going to be removed in a few weeks.

Over the course of time on this forum, I've read various posts, which suggest to me no MEIC or tests for very small jobs like replacing socket faceplates for example, or installing a new luminaire or even pretty much the installation I mentioned, i.e. not altering or adding to just moving cable/socket.

 

[westward10]

You need to provide some sort of proof of works done, I know some disagree but I will do one even if I have like for like replaced an accessory.

 

[Midwest]

You need to provide some sort of proof of works done, I know some disagree but I will do one even if I have like for like replaced an accessory.

Would you do all tests, as prescribed by BS7671? Don't feel if you have to answer that.

 

[westward10]

Would you do all tests, as prescribed by BS7671? Don't feel if you have to answer that.

Yes I do, the only one I might skip is IR between line/neutral. Ring finals I only tend to do end to ends at the board.

 

[Midwest]

Thanks westward for your replies, I had expected a few more views though?

 

[westward10]

Yeah so did I. If you based the MWC on the generic one in BS7671 the tests are quite straight forward. IR test and EFLI test which confirms Zs, polarity and earth continuity all in one test. It is only Zs which requires a reading.