consumer unit tripping

[b21playa]

installed kitchen light switch and flicked on, and it tripped the mains.

Checked and theres a short in the wiring between earth and neutral and earth and live. READ THIS VERY WEIRD

Followed this back to find the same in all ceiling roses.

If main consumer unit on, and mcb on for lights, short between earth & live and earth & neutral.

Main consumer on, mcb for lights off, short between earth & neutral ONLY

Main consumer off, no shorts

What could be causing this?

 

[DESL]

How are you measuring the 'short circuit'?

With a multimeter? set on continuity?

If main consumer unit on, and mcb on for lights, short between earth & live and earth & neutral.

WHAT!!! That would make the cct live!!!

Main consumer on, mcb for lights off, short between earth & neutral ONLY

Perfectly normal to read a very low resistance as N-E connection somewhere depending on earthing arrangement for the supply

Main consumer off, no shorts

You have now isolated the nuetral from earth

 

[ban-all-sheds]

If it wasn't like that before then it's probably something you did when you "installed kitchen light switch".

What exactly did you do, and have you checked to see if you damaged the cable when you screwed the switch into place?

 

[b21playa]

Yes with a multimeter set on continuity?

Ive checked for shorts in kitchen swich wire and nothing - so thats not it

 

[GaryMo]

The MCB only tripped after you had changed a light switch?

 

[b21playa]

The MCB only tripped after you had changed a light switch?

Well yes, but the wire seems fine - I will double check this out but disconnecting switch wire and checking again in isolating

 

[GaryMo]

What were the readings you obtained? Short suggests around 1ohm or maybe less depending on test leads.

 

[b21playa]

What were the readings you obtained? Short suggests around 1ohm or maybe less depending on test leads.

will check resistance tomorrow

 

[pdcelec]

why do people play around with dangerous things? Why Oh Why?

 

[Pengwyn]

When you rewired the switch where have you connected the earth to ?

Any chance of a photo of the back of the switch ?

A wild shot in the dark could it be a double pole switch with the earth connected to one pole and the neutral to the other !

 

[ColJack]

given that this thread is almost a year old I doubt he's not sorted it by now..