rcd circuit - fire alarms

[matt.leung]

quick question, do heat and fire alarms have to be on a RCD protected circuit,

 

[S60TEM]

To be honest, if possible I tend to not put them on the same RCD with sockets etc as the OSG etc reccomends Smoke alarm circuits etc are to be segregated from other circuits. Its best to put them on there own within the DB after the main switch but before any RCD's and change the MCB for an RCBO to comply with 7671 ie <50mm buried in walls etc etc.

 

[NozSpark]

Generally all T&E cables burried <50mm in a wall should have RCD protection according to the BRB

 

[S60TEM]

thats why I put them on an RCBO.

Nothing else within the installation will trip the safety circuit as they are completely seperate.

 

[NozSpark]

...also BS5839 requires that they do not share a RCD with a socket circuit

 

[Zeespark]

If doing a rewire, I tend to have the hallway lights on their own circuit with just the up and down smokes linked in, on a 2+5+5 board, and if done this way, don't forget to install a fused spur between the lights and smokes on the circuit.

AndyGuinness

 

[sparkytim]

...also BS5839 requires that they do not share a RCD with a socket circuit

Is that Part1 or Part 6?

 

[kme]

refer:

BS5839-1 : 25.2h

BS5839-6 : 15.3d

The domestic (dii) is pretty much as Nozzer says - but the -1 is a little stricter.

As for the O/P - it depends on the wiring method used. If req`d by 7671, then yes.

note to Zee - putting smokes on a fused spur from lighting circuit isn`t ideal - the fuse could blow (or be removed), the only indication being from the power lights on the smokes! Why put the fused spur in?

KME

 

[Zeespark]

I was only reading what I was believed to be in the Building Regulations, and the spur is for maintenance purposes only, local DP isolation. If I am incorrect I apologise.

AndyGuinness

 

[kme]

If its providing DP iso; then its switched. My concern would be unintended isolation, or someone forgetting to switch back on. I`m not saying you`re wrong about the building reg. mate; I`d just have concerns over the provision of such a switch - I can envision Joe Bloggs turning it off when he burns the toast; and not switching it back on!!!

KME

 

[Zeespark]

That's fine bud, I totally understand what you are saying, I agree with what you say. I am right trying not to get on the wrong side of the Building Regulations is all.

AndyGuinness

 

[fletchflash]

I generally try to avoid putting smokes on an RCD or RCBO. I try to avoid installing the circuit in a manner that requires rcd protection, then put it on a seperate MCB before the RCD's.

thats why I put them on an RCBO.Nothing else within the installation will trip the safety circuit as they are completely seperate.

Problem with them being on their own RCBO, which is what a few people and scams debate, is that if it trips out people wouldnt notice and its easy to power down and remove batteries (think tenants). If sharing with a lighting circuit then people notice if they trip, and theres no way of isolating the circuit by itself.

 

[batty]

I am sorry but if people are stupid enough to isolate a smoke alarm circuit really they should not be on this earth anyway. I think its all about putting them were they are not likely to go off. We went to centre parcs a few weeks back not sure who designed these chalets but they had put a normal smoke about four metres from the oven. They also had smokes in each bedroom so every time you did toast or cooked food in oven/hob they would all go off. They did have a hush on them but really they should not have been there. I think no matter what you do in life so idiot will do something stupid to put other people at risk.