rcd test tripping both sides

[electric8]

can anybody help i did a rcd test on a circiut on a split load board and it triped out both sides of the board . I then tested a circuit on the oyher side of the board and that rcd did then not trip .I have checked for any neutrals on the wrong side but cant see anything obvious .never come across this before and wondered if anybody knows what would cause this

 

[Octopus]

What have you, or anyone else been doing to the CU prior to this "fault" coming to light? How long has the CU been in?

 

[electric8]

Its a new board just fitted and all new circuits in a house renovation I assume builders have fitted it and I was asked to test, all dead testing was fine 3 rings and 2 lighting all rings fine all r1 r2 fine all IR >299

 

[telectrix]

disconnect all the circuits. then test RCDs. if they test OK trhen reconnect each circuit and test RCDs after each one. that'll trace the circuit that's causing the problem.

 

[Paul.M]

This sounds like a problem that I had a couple of years ago. I did the house rewire but it gets tested by the company spark (dont ask, he is a long story). Everything tested out great (as it should on a rewire) but when he put the cables back into the terms he did not mark them.......

He crossed over the incoming and out going legs to both RFC on both sides of the rcd's plus put a neutral in the wrong bar on one of the light circuits. What a rounded door handle.


Do a soft IR test on your L+N bars and see if something has been crossed over. Then look at each circuit one at a time (I'd start at the RFC) and identify each leg. The rest is just fault finding. good luck and give us an update with what youve found.

 

[rich.250]

Is the db itself wired right? As in manufacturers connections?? Had one that wasn't recently.
Or is is a split load (16th)
So the two Rcd's are in series? Effectively.
Hope this helps.

 

[electric8]

Thanks for that suggestion sounds like I will have to get involved in other peoples work i just wondered if i was missing something simple as all looks ok in the board and all the other tests are fine all wiring looks fine

 

[tony mc]

I take it your doing a PIR.

Have alook at the tails coming into the main switch for tightness !

 

[Octopus]

Sounds like fun to me. They aren't expecting you to do and EIC and LABc are they?

 

[electric8]

Yes checked all legs on rings and removed and reconnected all the circuits just to make sure that everything was in the correct neutral bar .The factory conections also look correct but they are in series

 

[Paul.M]

Its a new board just fitted and all new circuits in a house renovation I assume builders have fitted it and I was asked to test......

Oh dear, the builders did it. If i was you I'd ask for more moey now before you take all week to find out what they have done.

 

[rich.250]

Yes checked all legs on rings and removed and reconnected all the circuits just to make sure that everything was in the correct neutral bar .The factory conections also look correct but they are in series

Are they both 30mA??
If one is feeding the other then it should be a S type for discrimination.
But then you wouldn't have additional protection for those circuits (if required)

Sounds like a typical builder install.......
'This board was cheaper!! I could just put a Rcd that side too'!!!!!
Lol

 

[bigspark17]

RCD's wired in series.?? i would start there.. dual rcd boards with 30ma protection usually come factory wired in parallel.!!

 

[Octopus]

Have you got a picture of the CU with the cover removed you could post?

 

[rich.250]

RCD's wired in series.?? i would start there.. dual rcd boards with 30ma protection usually come factory wired in parallel.!!

Sounds like a 16th edition to me, and the main sw has been changed to a Rcd!
Probably because they were cheaper and the builder wouldn't know the difference.... Lol

 

[Liam12]

Had this on a rewire a year ago, later found one of the other sparks had wired the two way from the landing and hall wrong, 1mm's at bottom of the stairs with a feed and switch line, and a three core for the two way upstairs, the 1mm's for the hall light and the three core for landing light and switch fed it thinking it was a 1 gang switch not a 2 gang, could be a possibility

 

[electric8]

Thanks for all the help found the problem a screw had just nicked a cable causing a fault after i had done IR tests.

 

[Octopus]

Thanks for all the help found the problem a screw had just nicked a cable causing a fault after i had done IR tests.

Very odd conclusion. This should affect one side of the board not both!

 

[electric8]

Yes really baffling me but fixed problem redid all tests and everything now spot on .but having said that builders are stil on site and loosening fittings to decorate and tile behind and such, so may have been something else as well .but i am paid now and everything was perfect when i left it