RCDs trip under no load

[Shinner]

Hi (first post)
Has anyone had trouble with Wylex RCDs?
Just installed a consumer unit and both my RCDs trip on power on but with all MCBs off and unable to reset them.
Never used Wylex before so can I asume both RCDs are faulty?
Will pop out and get some replacements, but thought I'd ask if anyone else had come across this problem?

 

[WarrenG]

Hi (first post)
Has anyone had trouble with Wylex RCDs?
Just installed a consumer unit and both my RCDs trip on power on but with all MCBs off and unable to reset them.
Never used Wylex before so can I asume both RCDs are faulty?
Will pop out and get some replacements, but thought I'd ask if anyone else had come across this problem?

Welcome!

Seems a bit strange for two Rcd's to be tripping, have you checked the supply?

 

[Spudnik]

If you took the CU completely apart when installing, I reckon you have put the neutral cables back round the wrong way, maybe.

Either that or a borrowed neutral in the installation somewheres.

 

[bahco]

i was thinking the same as you jason but with shinner saying all circuits are in the off position would the rcd's still trip?

 

[Guest123]

Hey.

Agreed, definitely sounds like a neutral problem there somewhere, wether it's with the split load kit being incorrectly conneccted, or a neutral to earth fault possibly on both sides????

I wouldn't have thought that both RCD's were faulty.

 

[flip73]

i agree with the others something neutral earthfault some where either disconnect all neutrals &earth then power up see if it holds if it does add each circuit back one at a time this would give you a start point to investigate from
good luck

 

[Shinner]

Hi guys thanks for the response
Had a look earlier taking back the circuits in the neutral lines and it appears I have a neutral to earth fault somewhere in the ring circuit. Gonna have lots of fun finding the problem I,m sure. Any good places to start apart from disconnecting all equipment round the ring?

 

[flip73]

split ring in middle making 2 radials ,find the half with the fault then repeat until you find the faulty leg or equipment

 

[Shinner]

Sounds obvious now you've mentioned it
Cheers

 

[WarrenG]

Shinner,

Just check that the circuits you are supplying and being protected by each RCD, have their neutrals connected to the correct neutral bar for that side of the board.

 

[Shinner]

Hi
Removed all the neutrals except the ring and RCD still tripped so in effect I was only using one neutral bar. Reckon it has to be an earth/neutral fault.
Will let everyone know the outcome eventually when the owner allows me to do some invest.

 

[Spudnik]

Not teaching you to suck eggs, but make sure you have the neutrals on the right bar for the RCD!

You could have line into RCD1 and neutrals into RCD2 neutral bar.

Easy mistake to make, and i still do it now

 

[Shinner]

I always listen to advice.
I removed the second RCD and associated MCBs from the second neutral bar so that all was left in the whole system was the ring on one of the neutral bars. This circuit alone (even with the ring MCB off) would not allow me to set the RCD. I tried both lighting circuits instead of the ring to ensure the RCD was not at fault and they worked fine.

 

[mrloy99]

I always listen to advice.
I removed the second RCD and associated MCBs from the second neutral bar so that all was left in the whole system was the ring on one of the neutral bars. This circuit alone (even with the ring MCB off) would not allow me to set the RCD. I tried both lighting circuits instead of the ring to ensure the RCD was not at fault and they worked fine.

should be easy enough to check for a N/E short with a continuity tester.
check no appliances plugged in too.And check you have a complete ring on all legs,and that phase to phase and neutral to neutral readings are very similar on your ring.An incomplete ring on one leg could cause a trip.