Discuss ADVICE - Is rewire needed on 2 bedroom property ??? in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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Yes, 3 core for the interlink but ...
I am not an "expert" and don't want to be Mr know-it-all but; if you're running a separate way for the detectors then why RCD it? The danger is that it trips and you don't notice (and so loose your fire protection).

RCD is required for all LV circuits in the bathroom. So if you 12v the lights then you can run the smoke/heat detectors (with battery backup) from the light circuit without RCD.

That's my understanding (I may be wrong).
Laurie


As you say, you could well be wrong!
 
RCD is required for all LV circuits in the bathroom. So if you 12v the lights then you can run the smoke/heat detectors (with battery backup) from the light circuit without RCD.

As Murdoch says, maybe, but I think that some would argue against.

And also provided that you don't have any switch drops buried in the wall less than 50mm deep.
 
Far and away best to wire smokes in with a light circuit so if there is a circuit fault it is quickly apparent and highly likely to be fixed.

A fault on a dedicated circuit could go un-noticed for months or years by which time the batteries will be properly exhausted and the system totally useless. Or the batteries get taken out of the beeping smokes and promptly forgotten about.
 
Yes, 3 core for the interlink but ...
I am not an "expert" and don't want to be Mr know-it-all but; if you're running a separate way for the detectors then why RCD it? The danger is that it trips and you don't notice (and so loose your fire protection).

RCD is required for all LV circuits in the bathroom. So if you 12v the lights then you can run the smoke/heat detectors (with battery backup) from the light circuit without RCD.

That's my understanding (I may be wrong).
Laurie
I'm pretty sure that non rcd requires the 12v system to be selv. Would this be the case with electronic transformers?
the lighting circuit would also have to comply completely with being in earthed trunking, conduit where necessary
I would split the circuits with 2 RCD and have the fire det on its non rcd protected rcbo
 
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I'm pretty sure that non rcd requires the 12v system to be selv. Would this be the case with electronic transformers?
the lighting circuit would also have to comply completely with being in earthed trunking, conduit where necessary
I would split the circuits with 2 RCD and have the fire det on its non rcd protected rcbo

As far as I am concerned 522.6.102 says that I can use non-earthed steel capping on any concealed cables to avoid an RCD if I want to. That'll be for all the concealed cables of the light circuit not just the bathroom.

I think all those 12v transformer comply with SELV. It's certainly on the box of the one I have in front of me.

Laurie
 
As far as I am concerned 522.6.102 says that I can use non-earthed steel capping on any concealed cables to avoid an RCD if I want to.

Don't think so. It's only if the mechanical protection is sufficient to protect against cable penetration by nails, screws, etc that you can get away without earthing. I would say that ordinary thin galv steel capping is too thin to prevent cable damage.

522.6.101 (i), (ii) & (iii) refer to EARTHED covering, conduit and trunking.
 
I always put smokes on a seperate RCBO protected circuit , this way its not effected if any of the other circuits trip the RCD as for the comment i could go for years without being noticed , when they lose the main power supply they will bleep and then run off the internal batteries, when these batteries discharge or get low they will then bleep like any battery powered smoke detector , this will then alert you to the low battery and tripped RCBO
 
As far as I am concerned 522.6.102 says that I can use non-earthed steel capping on any concealed cables to avoid an RCD if I want to. That'll be for all the concealed cables of the light circuit not just the bathroom.

I think all those 12v transformer comply with SELV. It's certainly on the box of the one I have in front of me.

Laurie

Err, don't think so! Mechanical protection should be 3mm thick. See Q12 here:
http://www.esc.org.uk/industry/indu...wired-domestic-and-similar-installations/tion
 
I always put smokes on a seperate RCBO protected circuit , this way its not effected if any of the other circuits trip the RCD as for the comment i could go for years without being noticed , when they lose the main power supply they will bleep and then run off the internal batteries, when these batteries discharge or get low they will then bleep like any battery powered smoke detector , this will then alert you to the low battery and tripped RCBO

Err, yes! And that's when the batteries get removed and the smokes are promptly forgotten about.

How many more times do we have to see news items about kids being killed in fires with the rider "the smoke alarms were not working / had the batteries removed / etc etc". People don't care if the smokes aren't working, it doesn't affect them. If the lights don't work though they'll get it fixed.
It's the same reason why cars go mad at you with bongs and warning lights if you drive off without putting your belt on!
 
Totally agree with the smoke alarm circuit coming off a regulary used lighting circuit woooohooooo 2nd post
 
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Maybe he got confused??? A lot of contrary information for him!!
For my money >>> Domestic install..
Smokes off of regularly used lighting circuit..
Almost always do an all rcbo installation these days, satisfies todays regs and any they may possibly throw at us in the future..
My wholesaler last week done me a 10 way square d board with main switch and 8 rcbos £200.. Really a no brainer from there. The benefits greatly outweigh the (diminishing) cost difference. Even if im not likely to return to an installation i always try to make it as user friendly as possible. Easy access to joints or connectios etc having all rcbos also helps if there is a future fault. A correctly labelled board will quickly pinpoint the area where a problem is, which may be sorted out over the phone and should a visit be required saves time on fault finding etc
 
This is what confuses me ?

How do i know if somebody is not going to plug in an electric fire ??

The cooker is integral and only 2Kw so can that just go on the ring circuit ?

I am being swayed to fitting all RCBO's due to the number of circuits.

Made a phone call and got a qualified spark coming out, last time i looked at my 17th Regs book was when studying for apprenticeship 15 years.....:icon9:

15 Years ago and you were reading 17th.. Where did you buy your time machine from??
 

Reply to ADVICE - Is rewire needed on 2 bedroom property ??? in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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