Smokes & Heat separate circuit to lighting?

[LmarshallSparks]

Hi everyone,

I’m installing two smoke alarms and a heat alarm in a standard two-bedroom renovation. I was considering omitting RCBO protection for the smoke/heat circuits since they’re part of a safety system. Does that approach sound correct, or would it be better to integrate them into the lighting circuit instead?

Appreciate any advice!

 

[westward10]

It's fine doing that provided the RCD isn't required for additional or fault protection.

 

[James]

although it may be fine doing that, i prefer to have them on the lighting circuit.

after all, if they are separate and the breaker trips, eventually when the batteries fail they will be off and nobody will notice / care.

 

[littlespark]

I think most modern detectors beep if there’s a powercut…. Or have a “power” light … So you should know if the breaker tripped.

 

[LmarshallSparks]

although it may be fine doing that, i prefer to have them on the lighting circuit.

after all, if they are separate and the breaker trips, eventually when the batteries fail they will be off and nobody will notice / care.

Thanks all!

So it’s okay to put smokes on a RCBO circuit? I was taught to mitigate the RCD protection on safety circuits

 

[westward10]

If it is installed in such a manner and ADS is satisfied without an RCD it doesn't need one but putting it on an RCD is also fine.

 

[LmarshallSparks]

If it is installed in such a manner and ADS is satisfied without an RCD it doesn't need one but putting it on an RCD is also fine.

Okay so it’s a PME system so ADS could be met via the 6Amp Breaker!

Removing the RCD would mean chasing the cable deeper etc! So if it can go on an RCBO circuit then it’ll go on one! It does make sense to combine it with lights as then it’ll always be switched on

 

[littlespark]

Lights would be on rcd protection now if you were to minor works on that circuit.

The only thing that might dictate rcd for smokes is buried less than 50mm… unlikely you are going into a wall.
Or are you putting one on a bathroom? Also unlikely.


Is mains detectors called for, or could you fit the aico 10 year battery type with the radio interlink?

No redecoration required. Whole house fitted in an hour.

 

[brianmoooore]

If you make it easy for a domestic customer to disable smoke alarms, then they will, so definitely in with an important lighting circuit.
It's a property renovation, redecoration doesn't need to be considered, so hard wired is preferable.
They'll have battery back up, so the "safety system" not RCD protected is irrelevant.

 

[Teddy Lop]

I generally wire as a separate feed from a lighting circuit breaker. Figure it makes any testing or potential fault finding easier.

But yeah the "They" like smokes on circuits to which "power loss will be observed". And TBF some people seem remarkably resilient to the chirps of failing smokes, which seems incredible for someone who's a bit spesh with sensory input. Mind you, the "They" also require non-tamper battery backup (that's yer cheapskate 9v instead of recharging) but nobody seems to give a ---- about that do they...

 

[brianmoooore]

I generally wire as a separate feed from a lighting circuit breaker. Figure it makes any testing or potential fault finding easier.

Fully agree with this and should have included it in my last post. Separate circuit, all the way back to the CU, but then paralleled with a lighting circuit.

 

[LmarshallSparks]

I generally wire as a separate feed from a lighting circuit breaker. Figure it makes any testing or potential fault finding easier.

But yeah the "They" like smokes on circuits to which "power loss will be observed". And TBF some people seem remarkably resilient to the chirps of failing smokes, which seems incredible for someone who's a bit spesh with sensory input. Mind you, the "They" also require non-tamper battery backup (that's yer cheapskate 9v instead of recharging) but nobody seems to give a ---- about that do they...

Really really great advise! It will always be wired into the lighting at the breaker but it’s good to refresh! By that I mean ran back to the board not just taking from a switch or ceiling rose!

It’s settled the smokes will go on the downstairs lighting RCBO!

Thanks as always electrical over lords!