Is a keyswitch required for HMO emergency lighting?

flex_m · Apr 27, 2017

Hi all,

I'm technically a 'trainee' but in a months time I will finally have all the qualifications to apply for an approved electrician jib card.

The first job I will be undertaking is getting a house up to HMO requirements, which are outside the scope of bs7671 so it's all a bit alien to me.

I know the areas I need to cover with emergency lighting, but I'm unsure as to the requirements of a key switch?

The existing lighting installation is obviously wired in two core so the key switch would do exactly the same job as the breaker.

Any advice would be most welcome.

Thanks!

westward10 · Apr 27, 2017

An identified test facility is required for routine testing.

westward10 · Apr 27, 2017

To reply OP use the box at the bottom, to reply to someone just tap/click on the "reply" on their Post that way other members can see your reply.
In reply to your pm to me a protective devise would also isolate the general lighting which could be hazardous.

flex_m · Apr 27, 2017

westward10 said:
To reply OP use the box at the bottom, to reply to someone just tap/click on the "reply" on their Post that way other members can see your reply.
In reply to your pm to me a protective devise would also isolate the general lighting which could be hazardous.

Sorry!

I was under the impression you could install emergency lighting in an an existing two core circuit and switch the permanent line for emergency lighting tests.

westward10 · Apr 27, 2017

What do you mean by two core circuit I assume you mean two core and cpc. Yes that is the normal way to isolate the charge/ permanent conductor through a test facility.

flex_m · Apr 27, 2017

Yea two core as in permanent line from the board, looped through the fittings and spurred out to emergency fittings.

In a new installation I've always installed three core so the test switch only activates the emergency fittings and leaves the others on.

In this installation breaking the permanent line will cause all the light fittings to switch off (other than the emergencies). Which would be safe as all relevant areas will be covered by emergency lighting and all rooms have natural light.

But you said 'a protective devise would also isolate the general lighting which could be hazardous'

westward10 · Apr 27, 2017

How many em lights are there, you could always put in individual test facilities from each fitting.

davesparks · Apr 27, 2017

flex_m said:
Sorry!

I was under the impression you could install emergency lighting in an an existing two core circuit and switch the permanent line for emergency lighting tests.

That would be a very poorly designed installation, and possibly not compliant with the emergency lighting standards.

flex_m · Apr 27, 2017

I was assured that you can retrofit emergency lights into an installation wired as I said, is there any regulation you can give me that contravenes this? I'm really struggling to find any information about it hence asking the question here.

davesparks · Apr 27, 2017

flex_m said:
I was assured that you can retrofit emergency lights into an installation wired as I said, is there any regulation you can give me that contravenes this? I'm really struggling to find any information about it hence asking the question here.

Assured by who?
You'll find it in BS5266, I haven't got a copy to hand at the moment but you presumably have access to it if you are designing an emergency lighting installation?

D Skelton · Apr 29, 2017

In short, there's nothing stopping you from tapping off of the local lighting circuit to each individual fitting and using a breaker as your test facility. You better have a decent risk assessment in place however to justify this, plus a clause within the O&M manual making it clear that any testing must only be done during daylight hours.

If the client or one of their representatives decides to carry out a monthly test on them in the dark and falls over, you will be sued that's a guarantee.

I'd highly recommend you obtain a copy of BS5266 and learn it by rote because there is an awful lot to designing a compliant emergency lighting system, even if it's only a few cheap bulkheads in a three bed semi. An awful lot that I get the feeling you haven't even begun to consider.

flex_m · Apr 29, 2017

Yep, I think you might be right on that one, I've installed many emergency lighting systems in the past but never designed them.

I had no intention of carrying out the work before I was fully confident in what I was installing, that's why I came here for advice.

If the advice is buy BS5266 and fully understand it's requirements then that's what I'll do, even if it will be the yellow version that'll only be useful as toilet paper next year...

Thanks for the advice.

D Skelton · Apr 29, 2017

Buy the full version and not just the guide. As a designer the guide won't be enough.

I'd also recommend some decent software such as relux and draftsight/cad as you can effectively kill a number of birds with one stone when it comes to presenting design information, manufacturers data, calculations, lux levels and floor plans.

Also, if you're planning on doing emergency lighting design correctly, be prepared to lose out on 95% of your quotes to other sparks who think that just slinging some EM lighting in and hoping for the best suffices.

Essentially, if you're doing it correctly, expect that with even the smallest of projects you'll be handing over a reasonably hefty folder to the client containing all the above birds killed and more.

Below is part of a recent project of ours on Relux:

[ElectriciansForums.net] Is a keyswitch required for HMO emergency lighting?

davesparks · Apr 29, 2017

You don't necessarily have to buy a copy of a British standard, access to it is free via your local library. for a one off small job it may be a more sensible way to go.

D Skelton · Apr 29, 2017

It's more than likely not economically viable to carry out a one off small EM lighting job if you're looking to comply fully with the requirements of BS 5266

Is a keyswitch required for HMO emergency lighting?

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