Two way switch tripping lights

[johnnymacc]

Hi guys,
put a new c.u in today everything was going ok,till i realised the upstairs lights was just twin cable no earth wire rang the guy and he said price up to replace wiring in the meantime can you get me power on.Cut a long story short installed it as you would normally but the two way is tripping rcd.Its an old switch single wire to com wire in switch top com to bottom com and two twin cables l1 and l2 goes up to single wire to com n one twin l1 & l2 bit lost as to what to do.

Cheers in advance.

 

[bugsy]

Two way switching on landing shared neutral

 

[mrmatt]

sounds like a borrowed neutral

put up and downstairs lighting on the same side for short term fix untill you can fix the borrowed neutral problem

 

[rocker]

Our good friend the borrowed neutral

 

[rocker]

Dammit!

 

[rocker]

By the way, while I would recommend running a CPC on the lighting circuit, it is not absolutely necessary if you can fulfil the correct criteria, namely RCD protection, No class I fittings/switches and a labelled board. Check out the ESC's guides (on their website) for more details on this.

 

[Sav]

By the way, while I would recommend running a CPC on the lighting circuit, it is not absolutely necessary if you can fulfil the correct criteria, namely RCD protection, No class I fittings/switches and a labelled board. Check out the ESC's guides (on their website) for more details on this.

Rocker !!!
give us a chance !! Just logged on . lol
Sav

 

[Paul.M]

Yep I was changing and adding a couple of emergency fire lights today in my head office. Mcb off but wasn't told (by my "brilliant electrical supervisor") that its on the same bar as the main office. Cut t+e and then a big shout by all the office staff, yes I tripped the computer rcd and they all had to get rebooted. Needless to say I didn't get offered a cup of coffee all day long. Shared neutral/on the neutral bar in board can be a problem. Ps don't ask me why they have put the EM lighting circuit on the same as the computer socket circuit. After thus past few days I give up.

 

[bugsy]

Possibilty that the em's and computers are on a critical supply d.b.?

 

[johnnymacc]

Cheers lads,
just got out of shower and remembered an old spark telling me to always keep your lights on same rcd for exact same reason i'll do that tomorrow and he wants a price for rewiring lights anyway so should be able to sort it then.

 

[rocker]

Your old spark is a bit misguided I'm afraid. OK it will rectify the problem, but a borrowed neutral isn't really something you want to leave as is. I would nbot imagine the customer wants you to run a new neutral upstairs, but I would push for it. Mind you, if you're running a new CPC anyway I would do a new neutral while you're at it. Notes on your cert and some kind of label on the CU is going to be the absolute least you should do in this situation.

LOL @ Sav!