DIY emergency lighting and Part P

[epsilon4]

Hi all,

I'm thinking of installing a number of 12V, 11W lights like these along with a 12V AGM battery to provide automatic emergency lighting throughout the house when mains power fails (automatic switchover by holding a relay open with 12V DC via transformer from mains, relay close will power the lights).

The lights would all have their own 1A 12V fuses, with another appropriate fuse near the battery terminal. The lights won't be installed in the kitchen or the bathroom.

I'm unsure as to whether this kind of work is notifiable - from the Part P document:

Electrical installation is defined in the Building Regulations as fixed electrical cables or fixed electrical equipment located on the consumer’s side of the electricity supply meter.

..which might imply it's only mains-powered items which are covered?

(ok, holding the relay open to keep the lights off is connected to the mains, but would be covered by 'signalling, control and similar purposes'?)

I'd be interested what people think? Thanks for your help.

 

[holmslaw]

..

 

[OwainDIYer]

what happens if you lose light because a MCB trips, but it's a different circuit to the one operating the relay?

and a kitchen with hot pans and sharp knives is one place where emergency lighting is highly desirable.

 

[JohnW2]

I'm unsure as to whether this kind of work is notifiable - from the Part P document:

Electrical installation is defined in the Building Regulations as fixed electrical cables or fixed electrical equipment located on the consumer’s side of the electricity supply meter.

..which might imply it's only mains-powered items which are covered?

You may have missed the bit which says:

The requirements of this part apply only to electrical installations that are intended to operate at low or extra-low voltage....

... so, there seems no doubt that it is intended to apply to things which are not mains-powered. How you wish to view and deal with that is, of course, your decision, and not necessarily something which it is approprtaite to discuss here![/quote]

Kind Regards, John.

 

[JohnW2]

what happens if you lose light because a MCB trips, but it's a different circuit to the one operating the relay?

The answer to that is obviously to have the relay powered by the lighting circuit - or, if there is more than one lighting circuit, having a relay powered by each one, with the contacts in parallel.

and a kitchen with hot pans and sharp knives is one place where emergency lighting is highly desirable.

Agreed - and I suspect that this is one of those situations in which the existence of Part P (specifically, notification) is likely to result in a less safe electrical installation (in terms of the dangers associated with loss of kitchen lighting).

Kind Regards, John.

 

[ban-all-sheds]

I'm thinking of installing a number of 12V, 11W lights

What size cables do you plan to use? Remember that you won't be able to tolerate much voltage drop with CFLs - if it's too much they won't work at all, not just go a bit dim.

I'm unsure as to whether this kind of work is notifiable

Yes, it's notifiable.

Firstly, as JohnW points out the regulations apply to ELV installations just as much as they do to LV (see //www.diynot.com/wiki/electrics:voltage-bands for definitions of those terms), which means that the installation of the lights and cables must comply with P1. The easiest way to ensure that is to comply with BS 7671 - The Wiring Regulations.

And secondly, yes it's notifiable, even if you don't have them in a kitchen or bathroom because you're building your own ELV lighting system and that makes it a special installation.

You should read all of this:

//www.diynot.com/wiki/electrics:part-p

 

[ban-all-sheds]

But why go to all that bother just buy the purpose made product. http://www.emergency-lighting-direct.co.uk/emergency-bulkheads.html[/QUOTE]
Alternatively install something which doesn't make your house look like a car park or pedestrian underpass.



Sustained ones can be used as the regular lighting in kitchens and bathrooms etc.

And, of course, any fluorescent light can be converted to be a maintained or non-maintained or sustained one.

 

[JohnW2]

What size cables do you plan to use? Remember that you won't be able to tolerate much voltage drop with CFLs - if it's too much they won't work at all, not just go a bit dim.

The link provided by the OP indicate the voltage requirement being 11-15V - which would leave him with little room for voltage drop if he used a 12V supply. If one were prepared to ignore the regs as regards voltage drop (if they even apply to ELV lighting - to achieve 3% with mutliple 12V lamps would probably need pretty meaty cable!), it would make sense to use a 15V supply, and be prepared to accept a 27% drop!

Kind Regards, John.

 

[riveralt]

If one were prepared to ignore the regs as regards voltage drop (if they even apply to ELV lighting - to achieve 3% with mutliple 12V lamps would probably need pretty meaty cable!), it would make sense to use a 15V supply, and be prepared to accept a 27% drop!

Kind Regards, John.

Given everything that has been said and the amount of work and therefore money involved, it would probably be better if he just bought a couple of torches and/or candles - while waiting for that fateful day .

 

[epsilon4]

Thanks everyone for your replies, they've been very helpful.

I'll have a think about what to do next

(for those interested in my original plans - the relay would have been held open by the upstairs lighting circuit, and I was planning on running the lights from a central distribution box with 1A fuses, so only one light per wire to minimise voltage drop).

Just seen the last reply - torches would indeed be easier

 

[OwainDIYer]

Alternatively install something which doesn't make your house look like a car park or pedestrian underpass.

Eeeh, I've had some good times in pedestrian underpasses!

 

[radioredcat]

We live in what is locally dubbed powercut alley as we had a 2 hr powercut last friday during the day so lighting wasn't a problem on this occasion but it was when we had a 5 hr powercut earlier this year.

We use those led camping lights from the pound shop so we can hang them off the ceiling lights one provides enough light to see where you are going also we have plenty candles as well.


Andy

 

[ban-all-sheds]

Eeeh, I've had some good times in pedestrian underpasses!

Yes, but the judge made it quite clear last time that if you were up before him again you'd end up on a register....

 

[ban-all-sheds]

lighting wasn't a problem on this occasion but it was when we had a 5 hr powercut earlier this year.

5 hours is pushing it for COTS emergency lighting...

 

[bernardgreen]

Just seen the last reply - torches would indeed be easier

True but fitting one auto light may be worthwhile if only to find the torches and spare batteries. Batteries in torches seem to migrate to other things like toys and radios.

http://www.channelsafety.co.uk/products/lumen-8/ fitted so as to provide light on the stairs.

( there are other sources of emergency lighting )