consumer unit advice

[electrician4u]

Just had a look at a installation guide from Hager about wiring consumer units and they suggest it's ok to put a smoke detector circuit with a lighting circuit and shower on the same RCD. I thought that was strictly not recommended. from my experience it's the lights that trip most often.any thoughts?

 

[telectrix]

smoke detectors are best connected in to a frequently used lighting circuit, reason is , if the MCB trips, client will be without lights and get it sorted.

 

[mickys86]

smoke detectors are best connected in to a frequently used lighting circuit, reason is , if the MCB trips, client will be without lights and get it sorted.

Tis the way I've been taught as well 

 

[brucelee]

hi mate
you can do it either way but tels way will be more likely to be noticed by customer

 

[telectrix]

the problem with having a dedicated circuit for smokes is when her indoors burns the dinner ( so you know if you don't smell burning, it's salad day) , it's too easy for mr. numpty to isolate the smokes, thus rendering them useless ( because he can't be bothered to replace the batteries either. if in a lighting circuit, though, he'll soon reset it after he's fell over the cat in the dark.

 

[brucelee]

dedicated RCBO or regular used lighting circuit BUt I would always go for lighting circuit for domestic as both are stipulated in elecys guide to building regs and also manufacturers info
They both prefer lighting circuit
elecys guide say with a means of isoltion but no means of switching off so a unswitched fused control unit off the lighting circuit
the detectors and alarms are required to:
a) be linked so one will operate the other
b) be permanently wired with a independent circuit to the distribution board( ccu), OR PREFERABLY SUPPLIED FROM A LOCAL REGULARLY USED LIGHTING CIRCUIT, ( There SHOULD be a means of isolating the supply to the smoke alarms without switching off the lighting )
c) have a stand by power such as a battery or capacitor

Note mains powered smokes may be interconnected by radio links

 

[electrician4u]

That's all very well when electric smoke alarms have a battery backup, but what about mains only? surely must be on its own supply?and would any electrician connect to a light circuit, then put an unfused spur in the smoke alarm circuit-seems messy and an unnecessary expense.good point made about nuisance activation and the probability of it being switched off permanently though.

 

[malcolmsanford]

That's all very well when electric smoke alarms have a battery backup, but what about mains only? surely must be on its own supply?and would any electrician connect to a light circuit, then put an unfused spur in the smoke alarm circuit-seems messy and an unnecessary expense.good point made about nuisance activation and the probability of it being switched off permanently though.

Would you be thinking in a domestic situation of fitting Grade E smokes, most fire/LABC insist on Grade D for dwellings not over 3 stories.

 

[electrician4u]

i personally would fit with a battery backup but i've seen mains only connected, especially commercial and industrial and sometimes customers buy their own gear for me to fit

 

[malcolmsanford]

Well yes on commercial/industrial you will have the smoke via a detection panel and that as the battery back up.

Be careful of fitting non grade D type in domestic as they may not be approved by the LABC/Fire department and the BS 5839-6 recommends type D for dwellings not above 3 stories.

 

[electrician4u]

thanks for advice. i've learned something new.slightly troubling is if you look in Electrofix/Srewfix they sell smoke alarms with or without battery backup with no warning of use and even same model type.

 

[laws]

sorry could you just explain if you mean dipping the smokes in to the same MCB as lights or feed the smokes off one of the lights. im sure its the first but just clarifying

 

[malcolmsanford]

sorry could you just explain if you mean dipping the smokes in to the same MCB as lights or feed the smokes off one of the lights. im sure its the first but just clarifying

Either will be acceptable.

 

[marksparky]

but u must be able to isolate the smokes without affecting the lighting, i usually fit a double pole key switch surface mounted beside the consumer unit labelled as smoke detectors and feed it off 1 of the lighting circuits, i used to wire it on a circuit of its own but now i feel there is a better argument for wiring off the lights

 

[Des 56]

but u must be able to isolate the smokes without affecting the lighting, i usually fit a double pole key switch surface mounted beside the consumer unit labelled as smoke detectors and feed it off 1 of the lighting circuits, i used to wire it on a circuit of its own but now i feel there is a better argument for wiring off the lights

That may well be the result when they are unplugged from the base

 

[electrician4u]

I did mean coming off the same mcb yes.of course, the problem of any separate means of isolation will encourage people to switch it off if it's always activating but as people have mentioned there's a requirement to have separate isolation, so what to do....

 

[Des 56]

but as people have mentioned there's a requirement to have separate isolation, so what to do....

If there was a combi boiler with a plug and socket,that would be a suitable means of isolation
If there was a smoke alarm with a plug and socket for the base and the detector (eg aico ) what then ?

 

[marksparky]

hmmm i just wouldnt wire it straight into the lights without some sort of seperate isolater, just my personal preference, but if the whole base and detector was ever to be replaced i dnt think having to turn the lights off to change them is ideal just my opinion!

 

[Ponty Massive]

hmmm i just wouldnt wire it straight into the lights without some sort of seperate isolater, just my personal preference, but if the whole base and detector was ever to be replaced i dnt think having to turn the lights off to change them is ideal just my opinion!

I dont see a problem unless you're changing the unit in complete darkness?

 

[JUD]

hmmm i just wouldnt wire it straight into the lights without some sort of seperate isolater, just my personal preference, but if the whole base and detector was ever to be replaced i dnt think having to turn the lights off to change them is ideal just my opinion!

It has to have a means of isolation for maintenance/cleaning purposes. This can be done by disconnecting the smoke from it's base.

What do you do if you have to replace a light fitting. You don't give a means of isolation to each fitting do you? :wink5:

 

[brav]

It has to have a means of isolation for maintenance/cleaning purposes. This can be done by disconnecting the smoke from it's base.

What do you do if you have to replace a light fitting. You don't give a means of isolation to each fitting do you? :wink5:

Agreed, isolation by the lighting mcb and disconnecting frm its base should be enough as long as its clearly stated in the cu tht its connected to the lighting circuit. If u fit an extra totally seperate way of isolating just the alarm frm the lighting circuit u may as well of given it its own mcb for the customer to switch off when they get p***ed off. imo

 

[marksparky]

lol well isolation by the lighting mcb is hardly isolating with out affecting the operation of the lighting circuit is it? or do u guys use emergency fittings throughout domestic installations so wen the lights go out the batteries take over? Definition of isolation .... A function intended to cut off for reasons of safety the supply from all or a discrete section, of the installation by seperating the installation or section from every source of electrical energy (ie breaking live and neutral conductors). So unplugging a detector from its base is not seperation from every source of electrical energy, as the base which may need changed if using a different make of detector is still live. Im not saying anyone is wrong i just believe my way is the best way, on a further note if they want to turn the smokes off they will simply take them down, just because they are wired into the lighting mcb will not deter them, my keyswitch is clearly labelled smoke alarms do not turn off! if they choose to ignore that advice then thats up to them there is just no helping some people.

 

[GLENNSPARK]

Pull the smokes off a lighting circuit either split at the board or from a 3 plate it dont matter. Disconnect the alarm module from the backing plate is acceptable.....don`t see a problem with that but its a bit like the radials v rings innit? everyones got their own way of doing it and if its all compliant.....jobs a good un........