Smoke alarms and rcbo's - have looked at other threads but still no definitive answer

[ricardo123]

Hi All,

Quick question,

Have dual RCD board, one circuit on its own is a smoke alarm. I have read all this stuff about smoke alarms being on their own RCBO or with the RCD gang. Can someone please explain why it would be bad practice to put a smoke alarm circuit with others ?


My take:

If a smoke alarm can be put on the same circuit as lighting circuit which will be protected by the RCD then I can see no difference with the smoke alarm being put with the RCD protected circuits on its own circuit.

 

[Amp David]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

I see it the same way too.

 

[Graeme Harrold]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

For domestic, its normally the way to go as you will get an indication of a fault as your lights/sockets will also trip. If on an RCBO, if it trips, the occupier may be unaware that something is amiss..........then again they should also be battery back-up'ed.............Independant circuit will normally come as an installation spec or on higher rated (safety level) alarm systems.

 

[davelerave]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

i prefer the shared rcd and mcb rather than independent rcbo

to prevent the un-noticed trip,or occupier switching off the alarms




so i would wire it independently ,but 'bunch' it with the lights on a dual rcd board


that way if there's maintenance they can be separated at DB

 

[ricardo123]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

I agree if its on its own RCBO then you would think there is more likely hood that the occupier will not turn it back on. As you say a smoke alarm should have a battery back up, and you would expect it to start making an intermittent bleep without its power supply so really it shouldn't matter if its on one of the RCD gangs.

I have read on other websites that an RCBO smoke alarm is a must but it makes no sense to me. It seems over the top and unreasonable unless I have missed the point.

 

[ricardo123]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

I agree with you all so far, do you think some people on other websites are just making mischief or trying to sell more RCBO's!!!

 

[Hawk81]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

Hi All,

Quick question,

Have dual RCD board, one circuit on its own is a smoke alarm. I have read all this stuff about smoke alarms being on their own RCBO or with the RCD gang. Can someone please explain why it would be bad practice to put a smoke alarm circuit with others ?


My take:

If a smoke alarm can be put on the same circuit as lighting circuit which will be protected by the RCD then I can see no difference with the smoke alarm being put with the RCD protected circuits on its own circuit.

The reason why i dont put the smoke alarms on their own circuit is so that if there is a fault on the smoke circuit then someone can isolate the smokes without the fault being repaired. But if the smokes are on with the lights then they will be more inclined to get an electrician out to find and repair the fault.

 

[Guest123]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

Page 18 of this document, section 1.19.

http://www.planningportal.gov.uk/uploads/br/BR_PDF_ADB1_2006.pdf

Either is acceptable although slight preference is made to the local lighting circuit.

 

[Hawk81]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

These are also a useful piece of kit to fit at the cu.

 

[Graeme Harrold]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

Who does those then......?

 

[Guest123]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

My local authority specify those to be fitted in their properties

 

[BigBreakfast]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

Hi all,

Got a hint at a course recently that we may be heading to seperate circuits for smoke alarms in near future (Scotland). Cannot validate this though!

 

[davelerave]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

i suppose the concern with dual rcd is the amount/frequency of 'rcd downtime' possibly affecting the alarms

still never liked independent mcb/rcbo for domestic


the major risk is that the batteries start to beep and the occupier removes the batteries and switches off the mcb/rcbo

 

[rallyandy]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

hi i fit quite a lot of smoke alarms and agree with everyone on here that is better to feed from lighting circuit as less chance of them being switched off if a fault develops......... the control switch Hawk81 has displayed is made by Aico it has 3 switches on it 1 - locate ( to find which detector has been activated) 2 - test 3 - hush.... they come in hard wired or wireless...... i use the wireless system which is quite expensive but saves all the chasing of cables etc.... all you do is feed each detector from a light fitting and mount the control switch where you want, then push a couple of buttons and het presto they are linked together...... the battery in the control switch has a 10 year lifespan and needs no mains feed....... hope this helps

 

[Amp David]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

When taking a feed from a lighting point for each alarm, how do you go about isolation for the smoke itself. I thought you had to have seperate means of isolation for the smokes other than just the MCB for the lighting.

 

[rallyandy]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

i thought the same but in a conversation with the local senior fire officer he explained that because of the risk of someone switching them off due to a fault that the preferred method is off a lighting circuit so as to encourage the owner / occupier to get the faults rectified as they would have to turn the lighting circuits off etc to silence the alarms.....lol he said that the fire service weren't interested in us putting isolaters in as this would encourage them to be switched off in fault conditions and forgotten about and that fire brigade has duty to make sure all installed systems are operable. hope this helps Amp David

 

[Graeme Harrold]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

i thought the same but in a conversation with the local senior fire officer he explained that because of the risk of someone switching them off due to a fault that the preferred method is off a lighting circuit so as to encourage the owner / occupier to get the faults rectified as they would have to turn the lighting circuits off etc to silence the alarms.....lol he said that the fire service weren't interested in us putting isolaters in as this would encourage them to be switched off in fault conditions and forgotten about and that fire brigade has duty to make sure all installed systems are operable. hope this helps Amp David

That makes total sense, and as I usually do is take a feed from a light loop and then interconnect as required. MCB in the CU is marked as having the smokes/heat fitted with the stickers that come with the units.

 

[Amp David]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

Ok thanks guys.

If the alarms are from the lighting, i guess the lighting circuit would just be isolated then for maintainence reasons.

 

[rallyandy]

Re: Smoke alarms and rcbo's - have looked at other threads but still no definitive an

Yep thats right Amp David ....... as long they can be isolated for maintance or repair then you are covered in the regs and keep the local fire officer happy as well....also as Graeme Harrold states make sure you label which circuits are feeding the detector / detectors