30ma rcd tripping after replacing consumer unit

[muzza1]

Hello all, how are you?
I often look on here but the time has come to ask for some advice!
Nearly finished some alterations in a customers Kithen, Dining room, Utility room and Garage. Approx 3 days work in total.
Anyway, after all 2nd fixed and new split load board installed pop goes the rcd! Proper annoying!
It was found that when the ch+hw boiler was switched on at the spur it tripped the 30ma rcd on the split load board, here we go, i thought :sad:
Explained to the customer the situation and after bypassing the rcd hopped in the van knowing Monday is going to be a headache, (can't stand fault finding!)
To try and cut a long story short, i was after some advice or ideas re how to get round this problem without some testing deep within the customers boiler etc with certification and notification in mind!

I hope i've made some sort of sense with my question!

Thanks for any help on this chaps.

 

[muzza1]

Yeah Dave, thanks.

 

[Leesparkykent]

Not doing test results till tomorrow, kicking myself now as this problem could easily have been identified prior to adding to the circuit.

But you've energised the circuit without doing any testing.

 

[muzza1]

Yes, re energised the circuit which i should have tested first. Have you ever energised a circuit without testing it?

This ain't no wind up, just felt like seeking a bit of advice before going back to work tomorrow.

 

[Leesparkykent]

Yes, re energised the circuit which i should have tested first. Have you ever energised a circuit without testing it?

This ain't no wind up, just felt like seeking a bit of advice before going back to work tomorrow.

No....

 

[Midwest]

This ain't no wind up, just felt like seeking a bit of advice before going back to work tomorrow.

Ooppps, seems it isn't.

 

[muzza1]

Never energised a circuit without testing it, are you sure?

 

[Leesparkykent]

Never energised a circuit without testing it, are you sure?

When changing a board I carry out the dead testing on each circuit as im terminating them in to the new board.

 

[muzza1]

I guess that i've come a bit unstuck with the fault in the ch system being detected by the 30ma rcd. I'll get it sorted tomorrow.

 

[uksparks]

No....

I bet you have

 

[uksparks]

When changing a board I carry out the dead testing on each circuit as im terminating them in to the new board.

That's exactly what I do, I will have also carried out certain dead tests prior to agreeing to the work so i know what I'm in for.

 

[Leesparkykent]

I guess that i've come a bit unstuck with the fault in the ch system being detected by the 30ma rcd. I'll get it sorted tomorrow.

Yeah process of elimination shouldn't take to long to sort. If your not to familiar with heating wiring when you take the cover off the wiring centre take a picture on your phone before you start proding about in there so if you disconnect something or something pops out you have a reference to look at.

 

[HappyHippyDad]

Yes, re energised the circuit which i should have tested first. Have you ever energised a circuit without testing it?

This ain't no wind up, just felt like seeking a bit of advice before going back to work tomorrow.

I expect most Sparks have at sometime energised up a circuit before testing it, I expect it depends a bit on the size of the job. You're on a forum though Muzza where it's not really going to be something that many will admit to and also I believe the standard of work from forum members (and general interest in doing the job properly) may be higher than average.

I think I posted a thread back at the beginning of the forum about RCD tripping when I installed a new CU, I got a lot of stick (alot more than on this thread!), I ignored the bits that wern't helpful and I took on board the majority of the rest of the replies.

I can honestly say I will always do some basic testing of a CU prior to changing it now because that can save you a whole heap of trouble. If you quote for a CU change and then come across faults or Main bonding problems etc it would be unfair to expect the customer to pay, you could also get into a bit of a panic when it suddenly happens at 4pm when you're expecting to leave at 5!

Here are a couple of links that you may find useful:

http://www.electriciansforums.co.uk...ctrical-regulations/12971-cu-changes-you.html
View attachment CU check list.doc

 

[Leesparkykent]

That's exactly what I do, I will have also carried out certain dead tests prior to agreeing to the work so i know what I'm in for.

Yeah its the best way. Done a love job for a family member a few year ago and didn't carry out any pretesting. Changing the board testing each circuit as I go, come to the down stairs lighting and neutral is as flat as a fart to earth. Unscrewed all the ceiling roses...one cable in each fitting, unscrewed the switches...again one cable at the switches. Every lighting point had been JB'd before it was plaster boarded. It couldn't get much worse you would think...pulled the carpet back upstairs and its all tongue and groove boards . This was on a Saturday about 3 in the afternoon with no money in the job due to being close family. Since that day I've never changed a board without conducting some basic pre tests before hand.

 

[muzza1]

Cheers Lee, and hippy dad!
Interesting reading, thanks.

 

[davesparks]

I'll hold my hands up here and say I probably wouldn't have spotted this one until the circuit was renergised as I would have isolated the boiler before carrying out an IR test on the circuit. But I also would not have gone home without finding the fault as it doesn't take long to go through a boiler circuit and I don't want the liability of leaving a known fault in an installation.
Plus I have a very good working relationship with a local plumbing and heating company so can get pumps/valves/boiler internals fixed/replaced easily