consumer unit trouble
- Thread starter domster
- Start date
Sounds like a neutral has been put into the wrong place somewhere within the CU.
Your electrician really shouldn't have any difficulty spotting this
Your electrician really shouldn't have any difficulty spotting this
Is there a rating on BOTH the rcd's
ie 30 ma, 100ma
It may be the old one was 100ma and the new one 30ma
The fault may have always been there but not enough to trip the old one.
It does sound like a neutral to earth fault, due to various appliances tripping it.
It could be what RF said connected wrong, but the electrician (if any good) should have sussed that quicker than refitting the old unit
ie 30 ma, 100ma
It may be the old one was 100ma and the new one 30ma
The fault may have always been there but not enough to trip the old one.
It does sound like a neutral to earth fault, due to various appliances tripping it.
It could be what RF said connected wrong, but the electrician (if any good) should have sussed that quicker than refitting the old unit
Could the socket be fed with a borrowed neutral?
Surely that would have been spotted in an insulation resistance test? 
It happens
K
kkynaston
Do you have an RCD and a main switch?
A photo of the consumer unit would be really good here.
If you have a split board, you have 2 neutral bars.
One for the RCD protected side and one for the non-rcd side,
It is possible that the phase (live) from the cicuit is wired into the MCB on the RCD side and the neutral is wired into the neutral bar on the NON-RCD side.
Thus when ANYTHING is turned on, on that circuit, the RCD will operate as only the phase and not the neutral are going through the RCD.
If you electrician has disconnected the new RCD and put the whole board on the old RCD, then both the phase and neutral would be passing through it.
Hope you understand all this
A photo of the consumer unit would be really good here.
If you have a split board, you have 2 neutral bars.
One for the RCD protected side and one for the non-rcd side,
It is possible that the phase (live) from the cicuit is wired into the MCB on the RCD side and the neutral is wired into the neutral bar on the NON-RCD side.
Thus when ANYTHING is turned on, on that circuit, the RCD will operate as only the phase and not the neutral are going through the RCD.
If you electrician has disconnected the new RCD and put the whole board on the old RCD, then both the phase and neutral would be passing through it.
Hope you understand all this
The reason your radio does not trip the RCD is probably because the radio does not draw as much as 30mA of current and so is below the limit needed to trip the RCD.
It isn't a 'low voltage' radio it is a 'low power' one.
Do you have an RCD and a main switch?
A photo of the consumer unit would be really good here.
If you have a split board, you have 2 neutral bars.
One for the RCD protected side and one for the non-rcd side,
It is possible that the phase (live) from the cicuit is wired into the MCB on the RCD side and the neutral is wired into the neutral bar on the NON-RCD side.
Thus when ANYTHING is turned on, on that circuit, the RCD will operate as only the phase and not the neutral are going through the RCD.
If you electrician has disconnected the new RCD and put the whole board on the old RCD, then both the phase and neutral would be passing through it.
Hope you understand all this
Hphoto
View media item 1189
can you safely take a photo of the inside, with the cover off?
Turn off main switch first, keep fingers etc clear of internal parts especally around the main switch and any bare wires or metal screws.
It is the connection of black or blue wires to the brass bars that we are particularly interested in.
Turn off main switch first, keep fingers etc clear of internal parts especally around the main switch and any bare wires or metal screws.
It is the connection of black or blue wires to the brass bars that we are particularly interested in.
10p says he's got the in and out neutrals to the RCD the wrong way round 
Any takers?
Any takers?
Just being studying the photo, and that don't half look like a TT supply to me. It also explains why there was previously an RCD covering the whole installation.
OP, do you have an earth stake anywhere outside on your property?
A photo of the CU with it's cover removed would be really helpful
OP, do you have an earth stake anywhere outside on your property?
A photo of the CU with it's cover removed would be really helpful
Did your electrician give you an Electrical Installation Certificate covering the new consumer unit?
If so, could you have a look at the value recorded for Ze and the RCD testing which he did (or should have done)?
Lack of warning labels on the board lid and retest date may point to him not testing.
If so, could you have a look at the value recorded for Ze and the RCD testing which he did (or should have done)?
Lack of warning labels on the board lid and retest date may point to him not testing.
If he knew to test for Ze with the MEBs disconnected 
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