fitting mains linked smoke alarms - advice sought

[TryAnyJobOnce]

I am rewiring a house (doing the donkey work myself, and will have a qualified electrician inspect & test), and have just learnt that its probably going to be classed as an "HMO" and so need linked smoke alarms and maybe emergency lights. Please can anyone help with the following:

1. Is it correct that smoke alarms can be powered off a lighting mains? If so, can upstairs and downstairs alarms run off separate lighting circuits, and still be linked to one another?

2. Is there any requirement to use the red, fire-resistant cable seen in commercial properties' fire systems? If the answer to Q1 is "yes", then obviously the supply would be standard lighting cable, but what about the link cable? Or does one cable carry both power and link?

3. There are alarms which replace or supplement the ceiling rose, which also turn on the light when activated.
(a) How does this stand with the recommendation to position at least 12" from walls or lights?
(b) Does it turn the light on using the mains supply, or some sort of battery backup? If the former, does this count as emergency lighting, considering that it probably won't work if its an electrical fire?

4. Presumably a standardised protocol is used for the link, so I could extend without having to rely on finding the same model of alarm? Can I mix alarm-only, emergency-lighting-only and combined units on the same link circuit?

5. Does inspection/testing of a smoke alarm installation require additional qualifications to those for normal domestic wiring, and if so, is this something most electricians would be able to do, or do I need a fire systems engineer?

Looking forward to any advice you can give.[/list][/list]

 

[Taylortwocities]

I am rewiring a house (doing the donkey work myself, and will have a qualified electrician inspect & test),
]

I really hope you have already got an electrician who has agreed to do this. You'kll have a hard job finding one who'll sign off your work if they haven't been involved from the start.

1. Is it correct that smoke alarms can be powered off a lighting mains? If so, can upstairs and downstairs alarms run off separate lighting circuits, and still be linked to one another?]

If they are linked they will use the same power circuit. This can be a frequently used lighting circuit - better a dedicated circuit. Be aware of the requiremetns re RCDs and smoke alarms

2. Is there any requirement to use the red, fire-resistant cable seen in commercial properties' fire systems? If the answer to Q1 is "yes", then obviously the supply would be standard lighting cable, but what about the link cable? Or does one cable carry both power and link?]

In a domestic smoke alarm wiring you use regular PVC cable. It will need to be 3 core and earth

3. There are alarms which replace or supplement the ceiling rose, which also turn on the light when activated.
(a) How does this stand with the recommendation to position at least 12" from walls or lights?
(b) Does it turn the light on using the mains supply, or some sort of battery backup? If the former, does this count as emergency lighting, considering that it probably won't work if its an electrical fire?]

a) they are made to work co-located with the light
b) if the mains suppy is still present the lamp will come on. If the mains supply has failed there is a low level light - at least on the ones I've provided. Not much good in a house full of smoke IMHO.

4. Presumably a standardised protocol is used for the link, so I could extend without having to rely on finding the same model of alarm? Can I mix alarm-only, emergency-lighting-only and combined units on the same link circuit?]

There's no smart protocol - its just a simple on off signal. Dont even think of mixing manufacturers!

5. Does inspection/testing of a smoke alarm installation require additional qualifications to those for normal domestic wiring, and if so, is this something most electricians would be able to do, or do I need a fire systems engineer?
]

AFAIK there's no formal requirement for certification of a smoke alarm in a domestic premises. Some registration organisations (NICEIC eg) insist on a level of competence in the art of smoke alarm installation.



Hope this helps.

 

[TryAnyJobOnce]

Thanks, Taylortwocities, very helpful. Sorry that took so long, but I thought I'd make sure I knew where I was before coming back.

Yes, I did consult the builder's electrician beforehand, but didn't fancy tracking him down to ask daft questions and look like a complete idiot (and pay for the privilege!)

I'll use dedicated circuits - I haven't got a consumer unit yet, and I'll let the pro recommend/fit one according to what circuits I end up with.

I decided, in the end, to go for separate alarm and emergency lighting systems. I need 7 smoke alarms but only 2 emergency lights. I also need a heat detector, but the blurb I've found on the combined units doesn't say anything about linking to other detectors. Also, I'm not sure if an HMO counts as "home" use, but I suppose you can't trust a tenant not to put up an outrageous lampshade and mask the smoke alarm!

Don't s'pose you know anything about fire doors? (Only joking)

 

[ban-all-sheds]

Yes, I did consult the builder's electrician beforehand

Sorry to labour the point, but did your consultation result in him agreeing that he would certify to LABC that he did the electrical installation work, including alarms and emergency lighting, in this HMO? Signing the I&T part of an EIC is not enough.

If he isn't going to tell LABC that, did you notify them before you started, and are they happy with whatever arrangement you've made with the electrician for whatever I&T he is going to do?

 

[Simius]

1. Is it correct that smoke alarms can be powered off a lighting mains? If so, can upstairs and downstairs alarms run off separate lighting circuits, and still be linked to one another?

I'm pretty sure that 17th edition says it needs a dedicated circuit. I need to double check though.

 

[TryAnyJobOnce]

Sorry to labour the point, but did your consultation result in him agreeing that he would certify to LABC that he did the electrical installation work, including alarms and emergency lighting, in this HMO? Signing the I&T part of an EIC is not enough.

No, and I wouldn't want to ask someone to make a false statement. When I started (a long time ago, and I'm beginning to wish I hadn't!) I didn't think it would be classed as an HMO; estate agents seem to try to apply a looser interpretation than the local authority.

I haven't done anything towards installing the alarms & emergency lighting yet, so I could get him to do this.

Does the same apply to the rest of the electrics, for an HMO? If so, I guess I'm stuffed, and I'll crawl into a corner and die.

How much of the job of (re-)wiring counts as "electrical installation", in the sense that one might expect it to be done by an electrician? I mean, I can't see that taking up floors, drilling joists or chasing out needs a qualified person. Terminations probably do. What about running cables?

 

[Taylortwocities]

All of teh wiring works coults as "electrical installation" The elctrician who is signing the cert will be taking full responsibility for the job and saying he did it himself.

If you do some he will want to be involved in wire installation methods, routing of cables and sizing.

Some may be happy for you to do the donkey work and run in cables under his guidance. You'd need to find a spark who is happy to delegate some of the work to you and then carry out the second fix and testing.

 

[Lectrician]

I am rewiring a house (doing the donkey work myself, and will have a qualified electrician inspect & test), and have just learnt that its probably going to be classed as an "HMO" and so need linked smoke alarms and maybe emergency lights. Please can anyone help with the following:

1. Is it correct that smoke alarms can be powered off a lighting mains? If so, can upstairs and downstairs alarms run off separate lighting circuits, and still be linked to one another?

2. Is there any requirement to use the red, fire-resistant cable seen in commercial properties' fire systems? If the answer to Q1 is "yes", then obviously the supply would be standard lighting cable, but what about the link cable? Or does one cable carry both power and link?

3. There are alarms which replace or supplement the ceiling rose, which also turn on the light when activated.
(a) How does this stand with the recommendation to position at least 12" from walls or lights?
(b) Does it turn the light on using the mains supply, or some sort of battery backup? If the former, does this count as emergency lighting, considering that it probably won't work if its an electrical fire?

4. Presumably a standardised protocol is used for the link, so I could extend without having to rely on finding the same model of alarm? Can I mix alarm-only, emergency-lighting-only and combined units on the same link circuit?

5. Does inspection/testing of a smoke alarm installation require additional qualifications to those for normal domestic wiring, and if so, is this something most electricians would be able to do, or do I need a fire systems engineer?

Looking forward to any advice you can give.[/list][/list]

All these questions suggest you really should not be looking to do this yourself.

I rarely say this to posters.

You could cause yourself more grief by doing this yourself. It could end up costing you more in alterations to correct problems.

You would need to find a very amenable spark to do the test, inspect and cert for you. Most would run a while.

Oh - and how much work are you doing yourself? Whats "Donkey Work"? You may be offending several of the most regular posters by inferring their day to day work is "Donkey Work".

 

[Taylortwocities]

Lec, in his defence, 'twas I that said "DW".

 

[ban-all-sheds]

Does the same apply to the rest of the electrics, for an HMO?

Yes, but not because it's an HMO - the same applies because it is a dwelling.

If so, I guess I'm stuffed

'twas ever thus with people who embark on property development, or indeed any activity, without making sure they know what the laws are which apply to them....