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A supplementary question. 'Additional' RCDs come with a warning about
disconnecting before performing earth testing. Does this apply to a CU
one, and if so what is the method of testing such circuits?

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.

A supplementary question. 'Additional' RCDs come with a warning about
disconnecting before performing earth testing. Does this apply to a CU
one, and if so what is the method of testing such circuits?

Either bypass it or use a tester designed for the purpose.

The reason to bypass them is that the standard earth loop imdedence test
passes 20A from live to earth, which given that most RCDs are rated at 30mA
might just cause them to trip!

Christian.

In article ,
Christian McArdle wrote:
A supplementary question. 'Additional' RCDs come with a warning about
disconnecting before performing earth testing. Does this apply to a CU
one, and if so what is the method of testing such circuits?

Either bypass it or use a tester designed for the purpose.

Right. I doubt I could justify a new one, though.

The reason to bypass them is that the standard earth loop imdedence test
passes 20A from live to earth, which given that most RCDs are rated at
30mA might just cause them to trip!

I realise that, but wondered about the warning that comes with RCD
sockets. It suggests (to me) they may be damaged by testing?

--
*Money isn‘t everything, but it sure keeps the kids in touch

Dave Plowman London SW
To e-mail, change noise into sound.

I realise that, but wondered about the warning that comes with RCD
sockets. It suggests (to me) they may be damaged by testing?

All RCDs I've seen come with a warning to be removed when insulation testing
(presumably they either don't like the high voltage, or would affect the
result). This is usually in the form of a sticky label that you're supposed
to put by the consumer unit so that the sparky knows they should be looking
for one to disconnect. I can't see any reason to disconnect an RCD socket
for an earth loop impedence test unless you are intending to use that very
socket for the test.

Christian.