Smoke alarm

[jcwillis12]

Hi have to fit smoke alarms am i best to connect into existing lighting circuit or create a new circuit
Secondly have to fit a fuse spur into a 10mm twin and earth to run a tumble dryer, will a 30 amp fuse offer me protection
And lastly has anyone encountered problems with MK Dimmer switches have one which aint working
Thankyou for your advice. Justin

 

[Spudnik]

You are permitted to supply smoke detectors from an existing, regularly used lighting circuit or via separate circuit. However they should be interlinked either with wireless bases or hard wired. And you will also need to RCD the circuit you use issue appropriate certs for this work.

Depends on rating of tumble dryer.

MK dimmers, normally quite good. If in warranty send it back or replace with new.

 

[beaver74]

Secondly have to fit a fuse spur into a 10mm twin and earth to run a tumble dryer, will a 30 amp fuse offer me protection

not sure if you mean will 30A cover 10mm which is will,but you have trouble getting it in to a sw fuse and the tumble drier will have over current protection from the 13A fuse in sw fuse

 

[Paul_Rawlinson]

And you will also need to RCD the circuit you use issue appropriate certs for this work.

You will only need to RCD protect the circuit if the new cables (i.e smoke alarm cables) are buried in plaster less than 50mm deep.

Smoke alarms are safety device and so always better to put smokes on there own circuit. When a bulb goes often it will trip MCB or RCD, if this is the case and the smokes on the same circuit will go off. Although most have battery backup you should never depend on them

 

[jcwillis12]

thankyou foy youre advice

 

[uksel]

if it's for a landlord or HMO i think it has to be supplied from it's own breaker at the CU

 

[partp]

I would've thought it best to put smoke alarms on a lighting circuit via sw fuse, one that is used every day..( or should I say every night..) otherewise, if its on an independent circuit, then you could end up with the smoke alarm circuit being dead for weeks or months without noticing, whereas if its on a frequently used lighting circuit.. then the circuit will only be dead for a max of one day before you notice it. One day is still too long I agree, but its better than the alternative.. ie possibly several months.

 

[mdshunk]

Have you seen the new style fire alarm that they sell at the grocery store?

 

[uksel]

the fire/smoke alarms should have a battery back-up which would sound periodically under no-supply conditions to make the user aware that there is a problem, the feed is only required to charge the battery.

love the sifty pop alarm

 

[partp]

".... Although most have battery backup you should never depend on them"

as paul says above.. you should never depend on battery back-up alone, the intermittent 'beep' that sounds when the mains fails can not always be heard by elderly people, and even if it is.. they may not recognise it is a fault signal, they often will put up with it for a long time before they deem it to be a sign that something is wrong, but when that occasional and sometimes hard to decipher 'beep' is backed up by being plunged into darkness.. it covers all options and wether they are young or old, 'hard of hearing' or 'visually impaired'.. they will know there's a problem and get it sorted.
..The way I see it.. the bottom line is that running it from a sw fuse from the ltg circuit ads an extra layer of safety for the customer ( ie the ones that will hear and recognise the warning beep will hear it anyway, and the ones that dont will find out there's a fault when they try to turn the lights on) ..and its cheaper for the electrician and therefore for the customer to install it this way, so.. why not? (having said that.. there is probably a 'reg' somewhere that stops us from doing it the safest and cheapest way).