safe isolation devices

[gordy71]

Hi guys have got my first elecsa assessment in a couple of weeks. Think ive got everything sorted?! Just one las thing my mcb locks i use for safe isolation have regular brass padlocks, is this acceptable or will i have to source insulated ones? The c/u will be acting as a barrier if the cover is on wont it? Also for my EIC i was told it was acceptable to do an insulation test with the live and neutral connected, testing to earth so as to test the whole installation. The result that i got was 3.87 M ohms. This is acceptable but is it too close to 1? Would he expect me to investigate the circuits individually to find any latent faults? Or should i stop beating myself up?Wet Fish

 

[Manator]

The safe isolation procedure is a testing method to verify the circuit you are about to work on is dead. The CU will be switched off before you remove the cover, you then test on a known live source (the incoming tails) or proving unit, then test for any voltage on the outgoing side, then back to the proving unit to verify your tester is working correctly. At this point it is safe to disconnect any circuits that will be tested. A risk assessment must be made at this point as to determine if a lock off is required, if you are alone in the house with the assessor it may not be required, if it is required you would have to lock off the main switch and not individual breakers, this is because the cover will be removed during the tests. Your assessor is there to help, just stay calm and take your time.

Any suspect readings that you have put on your EIC will be noted by your assessor, and the low reading for the IR test may become a part of your assessment, there can be a few reasons why the reading is low, neons being one of the biggest culprits. Am I right in thinking that you have just changed the CU for this assessment? The reason I ask is that on a rewire all IR tests should be done before the fitting of dimmers, lights, and neon fused connectors.

Always read up on the testing procedures, even after many assessments its always worth going back to basics.

I have just re read your post, the IR test you describe was this for the whole installation? Or an individual circuit ?

 

[gordy71]

Yes the whole installation. The reason i did this was because it is a large house and was not 100% sure that i had disconnected all sensitive equipment ( hence L+N connected). Think i will go back and test each circuit individually. Being my first assessment i want to get everything spot on! Thanks for the reply manator. I actually had alot more questions but as i was writing and thinking how to word them i realised that most of them were silly and i knew the answers once i had thought about them! I hope my nerves dont get the better of me on the day because i do have confidence in my own ability, just fall to bits when a man with a clipboard is watching!

 

[m4tty]

The MCB lock you are using is the same as the one I used for my Elecsa assessment last year. Its fine mate (the brass padlock) .

I personally would IR test each circuit individually to find the suspect circuit which is bringing it down. Just for peace of mind and for learning also. I always do full tests when changing a board (IR every circuit individually) as im not that experienced. Im hoping that it'll all sink in and one day ill be able to cut the full testing down a bit but im still learning all the time so I test it fully.

Be interested for the outcome if you decide to test each circuits IR individually.

If you do everything (full testing) on your assessment, theres less chance to get pulled on something.

Good luck mate and report back once youve passed.

Cheers

 

[philbas]

When you say it's a large house, how many circuits?

Don't forget when you are testing the installation as a whole the circuits are in parallel, so for example if you have 10 circuits each with a resistance of 38 M ohms, the resistance for the entire installation will be 3.8 M ohms.

I'm not saying it shouldn

 

[gordy71]

ok will let you know the outcome, thanks for everyones help

 

[gordy71]

Retested all the circuits today individually, and found it was the upstairs ring that gave the low IR reading. Hunted around for ages for anything i had missed.

Eventually found a socket behind wardrobe with hair straightners plugged in. headbang .

Rest of circuits were fine.:worship

 

[Evans Electric]

Gordy, do a search on here for all the previous posts for guys waiting for assessment , it is a pain having a bloke watching with a clipboard , we all feel the same .

Personally I think its a load of ballcocks but we are stuck with it now . They are after your membership money so it appears that anybody gets in these days. TBH

Deke