Can radio linked smoke alarms be on different circuits, including a ring?

[HappyHippyDad]

I have just been to look at a job were the builder has started the first fix as I was unable to be there. He has forgotten to put in a cable to the heat detector in the kitchen, partly my responsibility as I should have reminded him more fully.

My plan is to have it radio linked to the hallway and landing smoke alarms.

The difference in this case is that finding a PL from a lighting circuit in the ceiling (now plastered) is going to be messy (just lots of SL's). Is there any reason why I cant take it from the ring as this would be easy? It would meet the requirement of regulation 433.3.1 (ii) for omission of overload protection.

 

[Sintra]

I would say yes as long as the manufacturers instructions don’t say that it has to be fused down.

 

[ImpededLoop]

Could you cut a drylining box next to it and install a fcu from the ring final?

 

[HappyHippyDad]

Could you cut a drylining box next to it and install a fcu from the ring final?

Well it's going to be taken from the single socket which is hidden in the extractor fan flue (I know that's not a good way of doing it, but again I have had very minimal involvement in the first fix), so I could put a FCU up high next to the extractor but trying to avoid unsightly boxes in a new kitchen. Plus, it could just be a spur from the ring, you don't need local isolation for smokes and it can be isolated as usual by the MCB. Plus it has fault protection from the 32A MCB.

All a bit shoddy, but not unsafe as far as I can see.

 

[ImpededLoop]

I haven't time this morning to check the BBB, but I always thought that anything connected to a ring final had to be fused down in one way or another.

 

[littlespark]

Is the extract fan supply on the ring or is it isolated from a switch?

Radiolink will work across different circuits...

 

[telectrix]

I haven't time this morning to check the BBB, but I always thought that anything connected to a ring final had to be fused down in one way or another.

i'd class a smoke detector as a fixed load, so technically, it does not require overload protection, just fault protection.

 

[ImpededLoop]

i'd class a smoke detector as a fixed load, so technically, it does not require overload protection, just fault protection.

Agree with you that it's a fixed load, but Appendix 15 shows only BS1363 accessories connected directly to the ring final. There is an example in A15 of a fixed piece of equipment being supplied via an fcu.

As with many things the BBB is not that clear on this one!

 

[Gavin John Hyde]

I have installed aico radio linked alarms on different circuits, some downstairs lights, others off upstairs light circuit.Ideal world would all be on one circuit.
if you approach aico ask them for a copy of the installers handbook. very useful little book.

 

[sparks1234]

Just a thought here, if you have the radio links installed, can they activate smoke detectors next door assuming they are same make etc?

 

[Wilko]

Just a thought here, if you have the radio links installed, can they activate smoke detectors next door assuming they are same make etc?

Hi - they have codes and we go through a commissioning process (button pressing and light flashing) to avoid that