Short on pos and neg

[Paul Hutch]

Hi all,

I've just installed a new consumer unit in my garage. No issues with that but the lighting I have installed has a short across positive and negative.

I have fault finded by disconnecting all cables and find no short. Including the 2 wall light fittings I have installed. But as soon as I connect it all together the short returns.

If I turn the lights on they work and do not trip out the breaker. Obviously though I don't want a short.

Any ideas as to what may be causing thismamy Thanks

 

[Darkwood]

You are getting a misleading reading more than likely, do you have any lamps in the circuit when testing?

 

[Paul Hutch]

You are getting a misleading reading more than likely, do you have any lamps in the circuit when testing?

Yes the lamps are in. I will take them out and do the test again and let you know. Thanks

 

[buzzlightyear]

I've just installed a new consumer unit in my garage. No issues with that but the lighting I have installed has a short across positive and negative

New consumer unit to outer garages will need to be part p.

 

[westward10]

As above you are reading the lamps, not a dead short as such as that wouldn't permit the breaker to switch on.

 

[Paul Hutch]

Yes the lamps are in. I will take them out and do the test again and let you know. Thanks

Lamps taken out and no short. I have 4 lamps and when I put 2 in no short but when I put in the 3rd the short returns.

My main concern is that when the lights when all on and fitted the short goes through to my other pos and neg circuits on the consumer unit

 

[Paul Hutch]

New consumer unit to outer garages will need to be part p.

The new consumer unit in garage is wired in 6mm sea cable and has its own RCD breaker. All other circuits are fine just the lighting circuit. But as advised it looks like I was picking up the lamps as the were in when cable tested

 

[Darkwood]

It is not a short, ignore it, you are seeing the low resistive values of a pre energised lamp when energised resistance and/or inductive fields will build up preventing shorts, this is why we remove all loads from circuits before testing to ensure no false positives.

 

[westward10]

The new consumer unit in garage is wired in 6mm sea cable and has its own RCD breaker. All other circuits are fine just the lighting circuit. But as advised it looks like I was picking up the lamps as the were in when cable tested

What Buzz was getting at is the installation of a consumer unit in a dwelling is notifiable to Building Control under Part P of the Building Regulations. This is a legal requirement.

 

[Paul Hutch]

It is not a short, ignore it, you are seeing the low resistive values of a pre energised lamp when energised resistance and/or inductive fields will build up preventing shorts, this is why we remove all loads from circuits before testing to ensure no false positives.

Thanks for you help. Much appreciated. Made my Saturday a lot easier. Can go enjoy the football now

 

[Paul Hutch]

What Buzz was getting at is the installation of a consumer unit in a dwelling is notifiable to Building Control under Part P of the Building Regulations. This is a legal requirement.

Ok sorry, I will get a part p electrician to sign off and check the work before fully using the consumer unit.

 

[westward10]

Can you show a pic of the consumer unit internal wiring.

 

[ipf]

I'm sorry, but talking 'pos and neg' doesn't wear with me. The OP hasn't the faintest idea and shouldn't be farting about with mains electrics.

 

[Pete999]

Hi all,

I've just installed a new consumer unit in my garage. No issues with that but the lighting I have installed has a short across positive and negative.

I have fault finded by disconnecting all cables and find no short. Including the 2 wall light fittings I have installed. But as soon as I connect it all together the short returns.

If I turn the lights on they work and do not trip out the breaker. Obviously though I don't want a short.

Any ideas as to what may be causing thismamy Thanks

You mean L and N POS and NEG are DC terms

 

[Paul Hutch]

You mean L and N POS and NEG are DC terms

Yeah L and N. Been working on a lot of fire alarm installs and got used to saying pos and neg