R.c.d tripping

[underpar12]

HI JUST INSTALLED A 12 way dual r.c.d. consumer unit.
problem is on the lighting circuits . at present i have both upstairs and downstairs and smoke alarm ,s on separate circuits,had to disconnect all three circuits to keep both r.c.d.s from tripping.out of intrest i tried all three circuits in a r.c.b.o on the non r.c.d. side but as soon as one of the circuits c.p.c our reinstated to the earth bar it trips out, started to check fittings etc seen that the smoke alarms have used the c.p.c as a interconnection. i am thinking also that some one has also linked both circuits together. so to recap as soon as one of the c p.c. is installed the r.c.b.o.s trip . any suggestions.

 

[Lighthouse Phil]

Check your neutral connections are in the correct place....make sure your neutrals are on the correct bar...1st place to look in this situation

 

[telectrix]

borrowed neutral , landing lights. try putting both lighting circuits in the same MCB. and obviously, the neutrals in the same neutral bar.

 

[not clever]

2 way switching down & landing

Tel beat me to it

 

[underpar12]

yeh thanks for your reply already checked neutrals restripped and refitted c/unit.tried removing neutrals one at a time no luck , at present iam thinking that the cpc of the smokes being used for the interconnections must be live and is connected in a jb somewhere. so linking the circuits together. the smokes only have one twin and earth in each fitting.i have tried all three in the same r,c.b.o. fine until i connect the or any of the three cpcs back in .

 

[Lighthouse Phil]

There was a similar post on here last night about using the cpc as a line conductor, a no no.
Sounds like you'll have to pull in a link for your smokes, and use the cpc for what it is and nothing else....

 

[gnselectricals]

You could use wireless interconnected smokes if pulling in new cables is a problem, have done this in the past & it works quite well


Sent from my iPhone using Tapatalk