smoke detector isolation

[17thman]

In domestic installations when using a regularly used lighting circuit to supply mains powered smoke detectors does anybody include an isloation switch for the smoke detectors?. thanks

 

[riveralt]

In domestic installations when using a regularly used lighting circuit to supply mains powered smoke detectors does anybody include an isloation switch for the smoke detectors?. thanks

I include a 3 amp Fused Connection Unit (or whatever the manufacturers instructions say) to allow disconnection when servicing - save having the lights off at the same time.
I tend to put the FCU high up near the ceiling.

 

[flameport]

No, since it just invites people to switch the detectors off.

 

[riveralt]

No, since it just invites people to switch the detectors off.

Just following the guidance given in Approved document B - 1.19. How do you achieve this?

 

[hotrod]

I include a 3 amp Fused Connection Unit (or whatever the manufacturers instructions say) to allow disconnection when servicing

lmfao

 

[flameport]

Approved documents are guidance only, and while much of what is contained in them is useful, that particular advice is poor.

The main reason for not fitting a switch/FCU or whatever is that the majority of smoke alarms I fit are in rental properties at the cheapest end of the market.
If there was any kind of switch it would be switched off and the batteries removed within a day.
That is also why they are connected to the lighting, and not a separate circuit at the consumer unit.

Even in better properties, an isolator is useless, since the only time the alarm needs to be switched off is when the backup battery needs to be replaced (many years with alkaline ones, never for lithium rechargeables) or the unit itself is replaced after 10 years.

The fact that the lighting circuit has to be switched off when replacing the alarm/battery is of no relevance, since smoke alarms are normally installed in areas which have windows.

 

[RMS]

I include a 3 amp Fused Connection Unit (or whatever the manufacturers instructions say) to allow disconnection when servicing - save having the lights off at the same time.
I tend to put the FCU high up near the ceiling.

Never seen this before. Do you service smoke alarms at night then?

 

[RF Lighting]

I've seen a lot of council properties done like that.

 

[riveralt]

I include a 3 amp Fused Connection Unit (or whatever the manufacturers instructions say) to allow disconnection when servicing - save having the lights off at the same time.
I tend to put the FCU high up near the ceiling.

Never seen this before. Do you service smoke alarms at night then?

Whats with the sarcasm?
The OP asked whether anyone fitted isolation switches for smoke alarms - I do.
The guidance given in Approved document B states the detectors and alarms are required to "be permanently wired with an independent circuit to the distribution board (consumer unit), or preferably supplied from a local, regularly used lighting circuit (there should be a means of isolating the supply to the alarms without switching off the lighting).
In addition, the manufacturers instructions also say that you should clean and vacuum these alarms on a monthly basis - with the mains supply isolated first.
I am always willing to learn so can you give me the benefit of your advice?

 

[RMS]

easy tiger

Your referring to guidance.

A well known manufacturer I use prefer that the alarms are supplied using a readily used lighting circuit. The manufacturer do not call for a means of isolation without switching off lighting circuit. I comply with this requirement in order to comply with 134.1.1.

Isolation is simple, isolate the lighting circuit for planned maintenance.

I feel from a design point of view your asking for trouble by installing another means of isolation.

 

[ricicle]

. Can you see the problem with putting an FCU or isolator in, when you have wired it off a regularly used lighting circuit ?

 

[kai]

Is there any reason why you can't put the Fuse-Connection unit on the ceiling itself? - Satisfies Part B of the Building Regulations and does the job. You could even have a neon indication on the FCU to show supply's healthy.

 

[ricicle]

I would rather use a keyswitch.