CU Change - Ring Tripping RCD Low IR

[markthespark]

Hi i went to change a CU last night and the ring main is causing the RCD to trip even with everything unplugged.

I am going back today to investigate abit more, i have just left the ring on the non RCD side for the time being.

The customer is as tight as and doesnt really want to pay for me finding a fault "as it worked before"

I am willing to spend abit of time looking for it for my own peace of mind but the house only has 1 ring so i can tell its going to be a nightmare.

Can i issue an installation certificate for the CU with low insulation resistance readings and note it in the comments?

or can i issue a EICR and recommend a rewire?

There is also no earth on the lighting but all the fittings are plastic, so i have recommended that the lights need a rewire.

 

[dazza1981]

Did you do any tests on the circuit prior to changing the consumer unit or did you discover the low insulation reading after you changed the board ???

 

[Farmelectrics]

Always do pre tests before changing cu why is there a non rcd side 17th edition cu have dual rcds just asking lol

 

[nickblake]

Possible a trapped neutral in one of the sockets , un plug every thing insulation test , it the old thing when you do a consumer upgrade "well it worked before " just explain how the RCD works with the old system working with a neutral to earth fault where as the new wont good luck in finding it

 

[Octopus]

EVERY quote / estimate you provide to clients for CU changes should always include a caveat that covers unforeseen issues - I've little sympathy for you.

And when you say "last night" exactly how long did you allow for the change and how much did you charge? A competent CU change will often take 1 day including all the paperwork.

Call you scheme's help line and ask for their advice - assuming you are legit!

 

[telectrix]

******* ****

 

[markthespark]

I got there about 3 yesterday due to taking my daughter to the docs didnt get home til 8pm!

No i didnt do any testing before i started as it was an old wylex fuse box all the wires were short and twisted together so i thought id do it when i had finished.

I am going to start by spliting the ring and narrowing it down that way.

My question is, where do i stand with the paperwork if the customer doesnt want to pay to get it fixed.

I did explain before i started that installing a new CU can flag up problems.

 

[markthespark]

Always do pre tests before changing cu why is there a non rcd side 17th edition cu have dual rcds just asking lol

It was one of those boards where you have to cut the busbar down yourself so i just made 1 of the ways non RCD

 

[telectrix]

you gonna have to bite the bullet and find the fault. might sound harsh, but it's your own fault for not carrying out a few basic tests before changing the board. start by splitting the ring final ​eliminate on leg, then split faulty leg down till you've located the problem.

 

[Octopus]

I got there about 3 yesterday due to taking my daughter to the docs didnt get home til 8pm!

No i didnt do any testing before i started as it was an old wylex fuse box all the wires were short and twisted together so i thought id do it when i had finished.

I am going to start by spliting the ring and narrowing it down that way.

My question is, where do i stand with the paperwork if the customer doesnt want to pay to get it fixed.

I did explain before i started that installing a new CU can flag up problems.

How can the CU change be "finished" if you haven't done the testing??

 

[markthespark]

Murdoch go back to bed im not looking for smart arse answers

 

[telectrix]

look on the bright side. you will have learnt as lesson the hard way. you'll not make the same mistake again.

 

[Octopus]

Murdoch go back to bed im not looking for smart arse answers

Smart arse answers - I think not. Just sharing good practice, not that you are interested.

 

[dazza1981]

Murdoch go back to bed im not looking for smart arse answers

But murdoch is right, you have only done half a job if you have not done the testing????

 

[nickblake]

What I would advise is as you are changing the protection parameters on a CU change never start one so late in the day start early this then gives you a chance to test and rectify any faults and you get home at a reasonable time bet its a trapped neutral

 

[Cbigfoot]

No i didnt do any testing before i started as it was an old wylex fuse box all the wires were short and twisted together so i thought id do it when i had finished.


My question is, where do i stand with the paperwork if the customer doesnt want to pay to get it fixed.

I did explain before i started that installing a new CU can flag up problems.

You can do an IR between lives and to earth from the busbar, no need to undo any connections.

if you explained that it can flag up problems and wrote it in your quote, i do not see the issue. You told them, there is a problem, it needs sorting.

If he won't pay it iooks like its your loss on this one. The fault needs clearing to connect to the RCD, and certify or you have just installed a white elephant in place of their wylex unit!

 

[Richard Burns]

Check the obvious that your neutrals are in the right N bar!
How low are your IR readings if they are less than 0.007 MΩ then this is a good place to start from
Try and assess the cable runs to look for obvious nails, screws and so forth in the wall at odd points.
But the chances are it is just a socket outlet cable trapped or scraped.

 

[MDJ]

Hi i went to change a CU last night and the ring main is causing the RCD to trip even with everything unplugged.

I am going back today to investigate abit more, i have just left the ring on the non RCD side for the time being.

The customer is as tight as and doesnt really want to pay for me finding a fault "as it worked before"

I am willing to spend abit of time looking for it for my own peace of mind but the house only has 1 ring so i can tell its going to be a nightmare.

Can i issue an installation certificate for the CU with low insulation resistance readings and note it in the comments?

or can i issue a EICR and recommend a rewire?

There is also no earth on the lighting but all the fittings are plastic, so i have recommended that the lights need a rewire.

TBH I am suprised you haven't been beat up over this, (message to the mods) - told you it was calmer now than a few weeks back didn't I :biggrin5:

 

[applemac]

You bad boy, test first, test good fit board. Test bad don't fit board- find fault- fix- test good, fit board. Simples.

 

[telectrix]

recipe for disaster... starting a job when you should already be in the pub.