Mains smoke alarms

JakeBates14 · Sep 21, 2016

Evening,

I've just been asked to install some mains powered smoke alarms to a customers property, can I still add these to an existing lighting circuit (if the alarms have a battery back up) or do I need a dedicated RCD Controlled circuit from the CU?

bigspark17 · Sep 21, 2016

Coming off an existing local lighting supply will be fine, providing if your cables are not running less than 50mm in plaster if they are then rcd will be required unless already in place.

ruston · Sep 21, 2016

Further to that you can use radio bases to interlink if running cables is a problem.

http://webarchive.nationalarchives....ortal.gov.uk/uploads/br/br_pdf_ad_b1_2013.pdf

Go to page 16 to give you the gist, and click the link to the right on your forum page to Aico.

haptism · Sep 21, 2016

If you use a dedicated circuit then It has been recommended to put the smokes on there own rcbo rather than bank it with other rcd protected circuits, due to if a fire trips something out it would also trip the smoke. On the flip side if it was with an rcd' lighting circuit and it tripped then it would be investigated because people usually investigate why their lights not on; whereas if it tripped on its own rcbo then it could be just switched off and forgotten about. So its horses for courses really, if you get what I mean.

Midwest · Sep 22, 2016

Not trying to be arse, but if there's a fire, hopefully the smokes should be sounding on the battery backups. I've read before, suggesting the smokes are on another circuit, but alarms I've had make that awful chirping noise, when the batteries drain down cos the RCD/mcb's has tripped. So can't see a reason to recommend either way as best policy?

ruston · Sep 22, 2016

Midwest said:
Not trying to be arse, but if there's a fire, hopefully the smokes should be sounding on the battery backups. I've read before, suggesting the smokes are on another circuit, but alarms I've had make that awful chirping noise, when the batteries drain down cos the RCD/mcb's has tripped. So can't see a reason to recommend either way as best policy?

I agree , the best way is to keep them off the RCD if possible.