Installed a new C/U now have fault

[Grant1987]

we can all throw the hats in the ring its down the the op to go and fault find .
learn once never again it will go down to experience, and we have all be there .

Yes that’s it the guy posting is obviously struggling with the fault and needs to learn how to fault find. In future I would advise anyone with limited experience to do the job during day time hours because it becomes more difficult when the dark nights kick in early

 

[Grant1987]

Not necessarily once you’re confident in fault finding can be easily rectified with limited time needed. All a learning curve though

 

[HappyHippyDad]

Yes that’s it the guy posting is obviously struggling with the fault and needs to learn how to fault find. In future I would advise anyone with limited experience to do the job during day time hours because it becomes more difficult when the dark nights kick in early

I'm not one of the crew that thinks an EICR is needed before a board change. I think that is way over the top. However, to just change a board without any kind of pre-visit check is just asking for trouble and isn't very professional.

You simply do a 15 minute pre-work check during your initial visit. During this visit you would do a global N-E IR test which would highlight a fault bad enough to trip an RCD (i.e < 0.01Mohms). You then give the customer a quote which includes the fault finding which generally you would do before hand.

The OP sounds new to this and I'm sure this will be a good lesson for him (i.e to check N-E before changing a board). Good luck in finding the fault chap. Stay calm and ask again on here if you get really stuck.

 

[MJPD29]

Interesting, any chance there's a borrowed neutral somewhere? What were IR readings on ring circuit?

 

[HappyHippyDad]

Not necessarily once you’re confident in fault finding can be easily rectified with limited time needed. All a learning curve though

If you had said can 'usually' be rectified with limited time, I would agree, but sometimes a fault can be really difficult to track down. I generally say to the customer I find faults within 2-3 hours (on average), just to give them a rough idea. I always add it could be shorter or longer. Sometimes it can be 10 minutes. Once it was 2 days!

 

[streamer]

The thing that I can’t get my head round is I have continuity end to end but on both legs of the ring I have a short between live and neutral,

It stands to reason that if you have continuity end to end that the same fault is going to show up on both legs unless you split the ring at a mid point. Also it could well be that your live to neutral 'fault' on the ring circuit is an appliance still plugged in or a spur switched on. Some are hard to find but remember things like TV splitters in the attic, spurs behind/above cooker hoods etc. So the fault causing the RCD to trip may well not be on the ring circuit.

 

[Grant1987]

If you had said can 'usually' be rectified with limited time, I would agree, but sometimes a fault can be really difficult to track down. I generally say to the customer I find faults within 2-3 hours (on average), just to give them a rough idea. I always add it could be shorter or longer. Sometimes it can be 10 minutes. Once it was 2 days!

Yes good point, we have all had a mere on certain jobs and a quick fix on others. Rough with the smooth I always say. Anyhow hope the guy finds the fault and isn’t stressing just got to stay calm and think of it logically

 

[davidanthony41]

New here so sorry if posted in wrong place,
I have installed a new consumer unit as the title says it’s a split load rcd board, anyway to the point one of the rings seems to now have a neutral fault which is taking out one side of the board I have checked all obvious things, touched no appliances since installing only moved the existing wiring to the new board location etc. The thing that I can’t get my head round is I have continuity end to end but on both legs of the ring I have a short between live and neutral, all I can think of now is to IRT the circuit and see maybe this could be down the the install being 30 years old and degraded T&E over time? Maybe the inner cores are now touching? Seems funny tho because the old c/u was old but was still rcd protected so surely that would of seen the fault? And surely both legs wouldn’t have sustained damaged when I’ve moved the cables?
can give me details if required thanks in advance

You might have mixed the neutrals up .there are two neutral bars one for each rcd

 

[Pete999]

Not a Borrowed N is it?

 

[SJD]

It would be nice if the OP could perhaps give us an update?

 

[DPG]

He's on the forum currently.

 

[Grant1987]

Don’t need to do an EICR beforehand, what difference would that make? When upgrading the consumer unit you have to do an install certificate anyway, Going back to the OP you need to use your tester to find the fault now, Split the ring at board then guess mid point one side should be clear with high readings the other 0 by swnds of it. Chase the fault is pretty much really easy when you understand the logic

Have had 2 x dislikes for this post, if you can explain you’re dislike that would be beneficial. I’m open for debate rather than a ?

 

[buzzlightyear]

Have had 2 x dislikes for this post, if you can explain you’re dislike that would be beneficial. I’m open for debate rather than a ?

Forearmed and forewarned comes to mind.

 

[telectrix]

i would not do a full EICR preceding a CU change, but would conduct sufficient tests to save a fault/s biting me in the arse. if the old CU has an upfront RCD that tests as OK , half the battle is won already.

 

[UNG]

It would be nice if the OP could perhaps give us an update?

I'm always suspicious of these threads when the OP hides their profile

 

[Midwest]

It would seem the OP was lulled into the false security of the original board had an RCD in it somewhere. But lets not scare him/her off the forum, and try and be as helpful as possible.

As I said yesterday with my thread, every day is a school learning day.

 

[SJD]

I'm always suspicious of these threads when the OP hides their profile

I suspect the OP only hid their profile after realising we knew he/she had been viewing this thread numerous times but had not responded (shortly after DPG's post #31)....

 

[UNG]

I suspect the OP only hid their profile after realising we knew he/she had been viewing this thread numerous times but had not responded (shortly after DPG's post #31)....

The profile was hidden early on long before post #31, I generally look at the OP and look at the profile of the OP before commenting and I lurked for a while on this one before making my comment

 

[Grant1987]

The profile was hidden early on long before post #31, I generally look at the OP and look at the profile of the OP before commenting and I lurked for a while on this one before making my comment

Yes is frustrating when people post on here with situations like the OP and then don’t give us the outcome or update, I understand if their busy then not always possible to reply straight away but at least reply. Anyhow if it was genuine hope he found the fault