RCD Tripping
 

I am installing electric in my garage. I have used 4mm T&E (about 25m)
inside which is protected by an RCD on the main consumer unit. The RCD
also protects the socket circuit for the house. I am using a 16amp MCB
for the cable. As soon as I test the cable the RCD on the CU trips,
the MCB is unaffected. I then wired the T&E to the MCB used for the
house sockets, once again the RCD trips. I thought it could be the
cable so I replaced that but after testing it happened again. Any
ideas?

Regards

Dr Jones

"DrJones" wrote in message
oups.com...
I am installing electric in my garage. I have used 4mm T&E (about 25m)
inside which is protected by an RCD on the main consumer unit. The RCD
also protects the socket circuit for the house. I am using a 16amp MCB
for the cable. As soon as I test the cable the RCD on the CU trips,
the MCB is unaffected. I then wired the T&E to the MCB used for the
house sockets, once again the RCD trips. I thought it could be the
cable so I replaced that but after testing it happened again. Any
ideas?

Not enough information to offer any opinion at all, but probably damaged
insulation or a connection error. Ideally a megger should be used to find
the problem/ check the insulation at 500v but otherwise get a £4.99 test
meter from Maplin and isolate the fault by opening the ring circuit at the
farthest point and check backwards for shorts on each half of the ring.

john

John wrote:

"DrJones" wrote in message
oups.com...

I am installing electric in my garage. I have used 4mm T&E (about 25m)
inside which is protected by an RCD on the main consumer unit. The RCD
also protects the socket circuit for the house. I am using a 16amp MCB
for the cable. As soon as I test the cable the RCD on the CU trips,
the MCB is unaffected. I then wired the T&E to the MCB used for the
house sockets, once again the RCD trips. I thought it could be the
cable so I replaced that but after testing it happened again. Any
ideas?


Not enough information to offer any opinion at all, but probably damaged
insulation or a connection error. Ideally a megger should be used to find
the problem/ check the insulation at 500v but otherwise get a £4.99 test
meter from Maplin and isolate the fault by opening the ring circuit at the
farthest point and check backwards for shorts on each half of the ring.

What do you mean by 'testing'. It sounds like the test procedure itself
may be teh problem.



john

It was somewhere outside Barstow when "DrJones"
wrote:

I am installing electric in my garage.

Get an electrician in. There appear to be so many problems with how
you've done this so far that I'm reluctant to advise further.


(At the very least, read a copy of the On-Site Guide and learn what
"test" means)

DrJones wrote:
I am installing electric in my garage. I have used 4mm T&E (about 25m)
inside which is protected by an RCD on the main consumer unit. The RCD
also protects the socket circuit for the house. I am using a 16amp MCB
for the cable. As soon as I test the cable the RCD on the CU trips,
the MCB is unaffected. I then wired the T&E to the MCB used for the
house sockets, once again the RCD trips. I thought it could be the
cable so I replaced that but after testing it happened again. Any
ideas?

Sounds like your house CU is a split load unit where the RCD protects
some of the circuits but not all. If this is the case then you probably
have the neutral of then new circuit connected to the non RCD protected
neutral bus bar.

Depends a bit on what you are doing to test it though...

Have you followed the test procedure in the On-Site Guide?:

http://www.amazon.co.uk/exec/obidos/...ternodeltdcomp

--
Cheers,

John.

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The Natural Philosopher wrote:
John wrote:

"DrJones" wrote in message
oups.com...

I am installing electric in my garage. I have used 4mm T&E (about
25m)
inside which is protected by an RCD on the main consumer unit. The
RCD
also protects the socket circuit for the house. I am using a 16amp
MCB
for the cable. As soon as I test the cable the RCD on the CU
trips,
the MCB is unaffected. I then wired the T&E to the MCB used for the
house sockets, once again the RCD trips. I thought it could be the
cable so I replaced that but after testing it happened again. Any
ideas?


Not enough information to offer any opinion at all, but probably
damaged
insulation or a connection error. Ideally a megger should be used
to find
the problem/ check the insulation at 500v but otherwise get a
=A34.99 test
meter from Maplin and isolate the fault by opening the ring circuit
at the
farthest point and check backwards for shorts on each half of the
ring.

What do you mean by 'testing'. It sounds like the test procedure
itself=20
may be teh problem.

maybe the old tongue test?

NT