RCD Tripping - WHY?!!

[atjhza]

Hi,

one of the RCD's on my board has tripped and I can't reset it.
I have turned off all of the trip switches for the circuit it protects but when I try to eliminate the offending trip switch, it makes no difference.

I assume that this means that there could be a short in an appliance/switch causing it cut out. I have checked and it would appear that a shower switch is jammed and cannot be turned to the 'off' position.

Is this likely to be the fault?

Any advice is really appreciated.

Thanks,

Alan.

 

[Taylortwocities]

The switch is probably jammed because there is a fault (maybe a bad connection has overheated the switch).

First off, turn all of the contact breakers OFF. Then try to reset the RCD.
Turn the contact breakers on one at a time. The RCD will probably trip when you turn on teh shower breaker.

That will confirm the culprit.

An RCD will trip if there is a fault on the neutral or the live.
The contact breaker only isolates the live leg.
Unfortunately this means that the method outlined above may not work if the fault is on the neutral conductor.

Give it a go and let us know how u get on.

 

[securespark]

I may have read it wrong, but I think the OP has switched off the breakers already.

It may be a neutral/earth fault, so you need to disconnect inside the CU....

 

[bernardgreen]

Some RCDs need to have the lever pressed all the way DOWN before they can be reset.

 

[rjm2k]

Hi,
I have turned off all of the trip switches for the circuit it protects but when I try to eliminate the offending trip switch, it makes no difference.

As mentioned above, possibly a neutral to earth fault which will not be eliminated by the MCB (they only isolate live not neutral).

I have checked and it would appear that a shower switch is jammed and cannot be turned to the 'off' position.

Sounds like you need to turn off the power and open up this switch to check it out, if you have some terminal block of the correct rating you could connect the wires going into the switch into that as a temporary measure to test whether it is the cause or not. May just need a new switch (make sure you get a shower rated switch).

 

[crystal ball]

Switch off the main switch on the CU and try resetting if it stays in you probably have a neutral fault, something like a screw head rubbing on a cable behind an accessory