UK Spur blowing RCD

[msteel9999]

I'm trying to connect a spur to an existing outlet but when I use an appliance on the spur socket the rcd trips.

I've tested the rcd and it has 19 amps capacity which is as expected.

I've also tried connecting to a different socket on the same rcd and it also trips.

What I don't understand is if I use the exact same appliance on the internal socket it doesn't blow.

I've also tried using a different external socket but the same result.

I've connected the socket with a heavy duty cable and so that the original socket has three wires in each of live, neutral and earth.

Any ideas?

Cheers

 

[littlespark]

What did you test red with? 19Amps? Do you mean 19mA on ramp test?

check you’ve got the rcd connected the right way round… incoming and outgoing.

photos of connections?

 

[johntheo]

Maybe a RCBO which can trip on o/load or earth leakage?.

 

[timhoward]

've also tried connecting to a different socket on the same rcd and it also trips.

What I don't understand is if I use the exact same appliance on the internal socket it doesn't blow.

Can you clarify:
You spurred off and added 1 socket.
That new socket with your appliance trips it.
Can you explain where the "different socket" is and where the "internal socket" is in relation to the original wiring and the spur, as one of them works and one of them trips it.

My long range guess is a Neutral - Earth short somewhere on the spur as it doesn't trip until the spur is used.

 

[msteel9999]

Can you clarify:
You spurred off and added 1 socket.
That new socket with your appliance trips it.
Can you explain where the "different socket" is and where the "internal socket" is in relation to the original wiring and the spur, as one of them works and one of them trips it.

My long range guess is a Neutral - Earth short somewhere on the spur as it doesn't trip until the spur is used

I have an internal socket on a ring which currently has 2 wires in each terminal. I added an external socket with a wire through the wall to the original socket.

 

[telectrix]

wired up wrongly or a conductor shorting out to earth.

 

[timhoward]

Double checking connections are correct is right at the top of the list. A plug in socket tester on the spur would be a helpful quick test.
If the connections are correct, and no obvious shorts then insulation resistance testing the new length of cable comes next.
Couldn't tell from first post if you have a multi-function tester, you mentioned RCD testing....

 

[msteel9999]

Double checking connections are correct is right at the top of the list. A plug in socket tester on the spur would be a helpful quick test.
If the connections are correct, and no obvious shorts then insulation resistance testing the new length of cable comes next.
Couldn't tell from first post if you have a multi-function tester, you mentioned RCD testing....

It's not the connections in the wrong place, I've had an electrician check them

 

[msteel9999]

It's not the connections in the wrong place, I've had an electrician check them

 

[msteel9999]

I have a multimeter

 

[msteel9999]

Also I should have said if don't use the I ternal socket and plug into outdoor socket it works

 

[DPG]

It's not the connections in the wrong place, I've had an electrician check them

Surely the electrician could have fixed the fault then??

 

[harv]

Surely the electrician could have fixed the fault then??

Thats what I was about to say... if an electrician has checked it, why didn't they find/rectify whatever the fault is?

 

[msteel9999]

Thats what I was about to say... if an electrician has checked it, why didn't they find/rectify whatever the fault is?

Nope. Otherwise I wouldn't be asking the question

 

[msteel9999]

It's not the connections in the wrong place, I've had an electrician check them

How would I resistance test the wire?