mains smoke alarm w/ battery backup

ShevY

just wondering is there any issue in the new regs with feeding a mains supplyed smoke alarm from a lighting circuit.

thanks.

ShamFeen

Keep them on an independant circuit and make sure if you have more than one that they're interlinked using the third wire at the smokie.

indie armada

is it ok to feed them from the lighting mcb or is a separate mcb required.
ive often seen them fed from ceiling roses.(dodgy):rolleyes:
another option is to feed them from your intruder alarm system if its easier then running a t&e back to the consumer board.

M cebee

the rules prob says independendent circuit

i prefer to connect them into a lighting mcb

Bruthal

Yea with a circuit wired back to the board for them i cant see a problem connecting the smoke`s circuit into the lighting mcb.

M cebee

it's prob better to double up with lights

prevents users switching them off easily

Bruthal

Yea an even better reason to double them onto the lighting MCB`s

M cebee

it's the preferred method really for domestic

M cebee

he did ask about the rules

last time i looked anyhow i think it said independent circuit

DublinDilbert

Quick related question, will ask here rather than start a new thread.

What's the latest regs for smoke / heat detectors? In a 3 bed semi is it heat detector in the kitchen and smoke at top of stairs (both inter-connected of course).

Is it normal just to use 3 core flex to connect them up? Can the earth be used as the signal wire? I assume the signal wire is low voltage as the system works in a power cut.

Has anyone tried these:-
http://www.meteorelectrical.com/fire-safety_smoke-detectors_220v-240v-ionisation-smoke-alarm-c-w-battery-back-up.html

Bruthal

In a standard three bedroom house, there would be a smoke detector in the hall, on the landing, in the living room, and in an attic if converted, and a heat detector in the kitchen.

I wire them in 1.5 twin and earth, and a single 1.5 pvc/pvc for the signal link. I wouldnt be a fan of using an earth core for anything except as an earth, even if the circuit does not require it.

M cebee

DublinDilbert wrote: »

Quick related question, will ask here rather than start a new thread.

What's the latest regs for smoke / heat detectors? In a 3 bed semi is it heat detector in the kitchen and smoke at top of stairs (both inter-connected of course).

Is it normal just to use 3 core flex to connect them up? Can the earth be used as the signal wire? I assume the signal wire is low voltage as the system works in a power cut.

Has anyone tried these:-
http://www.meteorelectrical.com/fire-safety_smoke-detectors_220v-240v-ionisation-smoke-alarm-c-w-battery-back-up.html

they need a separate base as well-it's on the website

don't use the earth for interconnect

DublinDilbert

Thanks guys!

TheBadBadger

M cebee wrote: »

it's prob better to double up with lights

prevents users switching them off easily

Good point, but having the fire alarm circuit independent from lighting has to be safer, no? I. E. If for whatever reason the selected lighting circuit were to trip out (I know, this would be a rare occurrence) during the night, you would have no audible fire protection!!

It would not be acceptable in a commercial, industrial installation.

TheBadBadger

M cebee wrote: »

it's prob better to double up with lights

prevents users switching them off easily

Good point, but having the fire alarm circuit independent from lighting has to be safer, no? I. E. If for whatever reason the selected lighting circuit were to trip out (I know, this would be a rare occurrence) during the night, you would have no audible fire protection!!

It would not be acceptable in a commercial, industrial installation.

M cebee

TheBadBadger wrote: »

Good point, but having the fire alarm circuit independent from lighting has to be safer, no? I. E. If for whatever reason the selected lighting circuit were to trip out (I know, this would be a rare occurrence) during the night, you would have no audible fire protection!!

It would not be acceptable in a commercial, industrial installation.

commercial panels are wired on a dedicated circuit

- alarms will function on battery if mains fails com or dom

http://www.eielectronics.com/images/stories/pdf/FAQs/smoke_qa.pdf

see no.17

our building regs for fire alarms are based on BS5839: Part 6

Bruthal

TheBadBadger wrote: »

Good point, but having the fire alarm circuit independent from lighting has to be safer, no? I. E. If for whatever reason the selected lighting circuit were to trip out (I know, this would be a rare occurrence) during the night, you would have no audible fire protection!!

It would not be acceptable in a commercial, industrial installation.

If the dedicated smoke detector MCB tripped, it would be no different than the lighting one tripping, except the lighting one is more likely to be noticed reasonably quickly. In domestic situations i usually connect them to a lighting circuit.

Battery will operate them perfectly well during mains off times.