please help !!! RCD Poblem

[cyberjunction]

Hi

I am doing my first consumer unit for my assesment on Friday and have come a cropper.

I have put in a split dual consumer unit, Wylex.

On the one half, closest to the main switch, the rcd works fine.
The second RCD, the test button does not work . When I apply a load ie upstairs kights , it trips straight away.Obviously thought the RCD was faulty so took it back and got it replaced and the same problem. I have disconnected all lines form the MCB and the buzz bar but the same problem. I have ensured there is no connection between the neutrals on the neutral bars as some one suggested and am completely stuck,

Can anyone help, I am panicking with my assesment due and am hoping this is something silly.

Just a note there is voltage to the RCD.

the preivous consumer unit was a single rcd and MCDs with problems

Thanks

 

[SPARTYKUS]

cyberjunction, I am not far from Reddich (?) - in fact working in Kiddi tomorrow. email if you want me to have a gander. Seriously.

Nick

 

[cyberjunction]

thanks Nick
would really appreicate the sanity check
cheers

 

[Martin Bradley]

once fault is found note it into a book for reff. type of problem and how you found correction method.

 

[MarkP]

once fault is found note it into a book for reff. type of problem and how you found correction method.

And let us lot know on here what the problem was!!

 

[DoBBY]

If the new fuseboard & RCD's are wired correctly then the best bet is to turn off all the MCB's off, then reset the RCD and switch the MCB's on one at a time until you find the circuit that is causing the RCD to trip.

This, this this!!!

 

[drew35]

I fitted a new consumer unit the other day where one rcd tripped as soon as you applied a load, I traced the split load cables to the rcd to find the live going into the supply side, but the neutral was entering the load side. It had been supplied like it, you could switch the rcd on as long as none of the mcb's that it fed were on. Trace the cables and think about where they should be going.

 

[cyberjunction]

just an update as promised
basically after reading all the suggestions I started to take circuits out one by one. Luckily the first one was the cooker which previously was not on an RCD did the trick, each time the cooker is swtiched on it trips the RCD, taking it out of the circuit cured the problem and the test button now works !! I just now have to decide on why the cooker is tripping the RCD even when the cooker switch is on and only the clock is displayed so very little current.
thanks to everyone for all your suggestions, really appreciated

 

[tony mc]

Cooker elements are often a good leakage to earth moneys on that !

Thanks for getting back !!

 

[telectrix]

suspect a N/E fault in the cooker, or possibly N/E reversal in cooker switch or outlet.

 

[thekingiam]

oh i love a happy ending !!

 

[SirKit Breaker]

I'm with Tony here. Seen this a lot, you have 2 or more Lines into one fuse, you change the board, split the lines up into different sides of the board, then when you turn on the landing light the RCD trips, because when the house was wired they only ran one neutral round the whole lighting circuit.

Cheers............Howard

 

[telectrix]

howard, you nbo bin reading proper. he tracked it down to cooker.

 

[SirKit Breaker]

howard, you nbo bin reading proper. he tracked it down to cooker.

Usual problem, not read all the posts again

 

[Deleted member 9648]

Still cant see how a fault on a circuit would affect the RCD test button??.....suggestions anyone?

 

[alanl]

Neutral to earth fault.
Even if the MCB for the faulty circuit is off, the RCD will trip. It will not reset, so the test button will not work.