spur from smoke alarm????

[carlbold]

Just wanted to have a bulb in the loft but the only live wire up there seems to be the one going to a smoke detector. It's quite a thick grey wire so maybe I could cut it, connect another wire that goes to a switch and then up to a light bulb....What do the pros think????

 

[sparkmanc]

It's common to feed a smoke alarm off the lighting circuit, so I don't see why not. Just make sure you use the correct cable, and correct protection. (6A for 1.5 Twin)

 

[RF Lighting]

Personally if the smokes are on a dedicated circuit then I would strongly advise against any tinkering with this circuit.

If you get it even slightly wrong then you are putting yours and your families lives at risk of failed smoke detection

 

[reggie perrin]

Personally I don't think smoke detectors should be on a dedicated circuit.

Nuisance 'beeping' etc. etc.

 

[plugwash]

smoke alarms should be either on a dedicated circuit or a LOCAL lighting circuit. Adding a loft light to a dedicated smoke alarm circuit is a teriblly bad idea because it means a much higher risk of the circuit being tripped without providing much indication that it has tripped. (with a local lighting circuit the principle is that a lightbulb failure may well trip it but when it does someone will notice and reset it pretty damn quick.

 

[carlbold]

Thanks for your input guys. I checked and the smoke alarms have a dedicated circuit so I'll leave it alone.
On the other hand, how about using the live wire of the bathroom fan?

 

[sparkmanc]

smoke alarms should be either on a dedicated circuit or a LOCAL lighting circuit. Adding a loft light to a dedicated smoke alarm circuit is a teriblly bad idea because it means a much higher risk of the circuit being tripped without providing much indication that it has tripped. (with a local lighting circuit the principle is that a lightbulb failure may well trip it but when it does someone will notice and reset it pretty damn quick.

Fair poiin but the ones I fitted had a battery backup, and a very annoying beeper when they come into use.

 

[sm1thson]

Fair poiin but the ones I fitted had a battery backup, and a very annoying beeper when they come into use.

but it also works the other way! -when the backup battery is flat it beeps, after a while the owners get fed up and turn off the mcb feeding it! -if its on the light circuit they have to leave the mcb on (if they want light) and replace the battery to stop the annoying beeping!

 

[plugwash]

or just rip the thing off the ceiling leaving a live wire dangling.

 

[CallEdsFirst]

Thanks for your input guys. I checked and the smoke alarms have a dedicated circuit so I'll leave it alone.
On the other hand, how about using the live wire of the bathroom fan?

Chances are that the fan is off the lighting circuit too! Sounds to me though (no offence) you might not be the best person for this job.

 

[wywywywy]

Sorry if I have missed anything obvious but... if you want a light in the loft, then why not get the power from the existing lighting circuit??

 

[CallEdsFirst]

I had assumed that this was not possible for reasons unknown!

 

[sparkmanc]

Fair poiin but the ones I fitted had a battery backup, and a very annoying beeper when they come into use.

but it also works the other way! -when the backup battery is flat it beeps, after a while the owners get fed up and turn off the mcb feeding it! -if its on the light circuit they have to leave the mcb on (if they want light) and replace the battery to stop the annoying beeping!

Again fair point, but;

A) I was FOR feeding it off the lighting circuit!

B) Anybody who turns off the detection deserves a slap! Maybe not a house fire but a good ****ing wake up call anyways!

 

[carlbold]

Sorry if I have missed anything obvious but... if you want a light in the loft, then why not get the power from the existing lighting circuit??

Well....all the ceiling roses don't have a live wire and there are no junction boxes in the loft. I just want to avoid the hassle of trying to route a cable down to a light switch

 

[CallEdsFirst]

Well....all the ceiling roses don't have a live wire and there are no junction boxes in the loft. I just want to avoid the hassle of trying to route a cable down to a light switch

I bet they do! I'd be surprised if they only had a switched live, but they definitely have a live! No sign of a loop terminal being populated? If one light leads to another, then there will definitely be a permanent live in there, other wise you would have to have the landing light on to get the bedroom light to work for instance!