EIC or MWC

Question

Scenario: 
 Existing lighting circuits with fluorescent luminaires upgraded to LED equivalents. 
 Circuit breaker changing type and/or rating. 
 Contractor has provided an MWC covering the works. 
 All looks good, but because the circuit protective device is not strictly a like for like change, should they have actually provided an EIC?

AJJewsbury · Answer

Humm. Personally (and this is just my personal opinion) re-terminating existing cables into a new DB constitutes work that has has the potential to introduce new problems - insulation may be been damaged on sharp edges, conductors (especially c.p.c.s) broken or imperfectly terminated, or even L-N reversal on the output of the RCBO. Hopefully good workmanship should minimise the chances of such things happening, and diligent visual inspection may pick up some problems. Some risk remains though I feel, so I would be happier if some inspection and testing had been done to verify a.f.a.r.p. that no new faults had been introduced. I wouldn't necessarily expect a full I&T on the entire circuit - an R2 and polarity tests to the first accessory and L+N to PE insulation test (perhaps even at a reduced voltage) to verify the reading is no worse than before (even if it's <1M) might well suffice.Of course the results want writing down in some form if you wish to prove at a later date that things were done sensibly. 
 Of course negotiating the time to do a job properly is a matter of contract (along with any consequent limitations) but such things should be sorted out before rather than after.. 
 - Andy.

AMK · Answer

I recently attended an educational webinar entitled &ldquo;Top Tips for Completing Certificates and Reports,&rdquo; which is part of The Wire series hosted by the NICEIC. The session provided a comprehensive overview of the appropriate utilization of electrical installation and minor works certificates. The content was delivered with remarkable clarity, offering valuable insights into the specific circumstances under which each type of certificate should be used.

Chris Pearson · Answer

Interesting - I can see both sides of the argument, but what they did seems reasonable to me. Had the final circuits not been in date, it would have been a different matter.

Ppod · Answer

The change of the consumer unit and the connection to it of the existing circuits have to be verified as safe to be put back into service, through the testing and the recording of results. You should have a schedule of test results with the installation, covering all of the circuits that have been connected to the new consumer unit

Ppod · Answer

https://www.electricalsafetyfirst.org.uk/professional-resources/best-practice-guides/#g1 
 if you have a look at part 7 of this guide it tells you the testing that they should&rsquo;ve carried out and recorded on your schedule of test results

AJJewsbury · Answer

All looks good, but because the circuit protective device is not strictly a like for like change, should they have actually provided an EIC? 
 
 The suitability of a protective device can be undermined by other changes - e.g. lengthening a circuit (so increasing Zs) or selection of conductor c.s.a for an addition - things that should be adequately covered by an MWC. Changing the details of the protective device while keeping the circuit length/conductors the same doesn't really raise any different issues. 
 The details of the design, inspection and testing should be the same whatever shape piece of paper it's recorded on, so as long as all the necessary details were there, I'd be happy with an MWC or EIC or even something bespoke made up to suit the particular situation. The ones in BS 7671 are only examples (models) after all. 
 - Andy.

EIC or MWC

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