emergency lights and key switches

[sparkymoscow]

Hi,

I am trying to teach myself how to wire and connect emergency light circuits. The guy I work with is not really interested in explaining things properly, so I am asking the forum for some knowledge (as I am a trainee still).

I know some of the basics, but just wondered how you guys wire your emergency light circuits from the board to a key switch and then to the lights.

I was told that you take a feed from the DB to the key switch common, then from the key switch common loop out to the lights (in our case we use a lot of klick boxes). The perm feed to the emergency light battery comes from L1 on the key switch.
I was told this was because the testing of an emergency light should not actually turn the light off so it is in emergency mode, but the light should remain fully on.

Is this correct and are there any other methods of wiring?

Also how do you guys wire lighting circuits containg key switches in say various rooms next to the light switch?

Hope this is clear.

I apologise if this is a basic question, but i would really like to get to grips with this.

Thanks

 

[accordfire]

Hi,

I am trying to teach myself how to wire and connect emergency light circuits. The guy I work with is not really interested in explaining things properly, so I am asking the forum for some knowledge (as I am a trainee still).

I know some of the basics, but just wondered how you guys wire your emergency light circuits from the board to a key switch and then to the lights.

I was told that you take a feed from the DB to the key switch common, then from the key switch common loop out to the lights (in our case we use a lot of klick boxes). The perm feed to the emergency light battery comes from L1 on the key switch.
I was told this was because the testing of an emergency light should not actually turn the light off so it is in emergency mode, but the light should remain fully on.

Is this correct and are there any other methods of wiring?

Also how do you guys wire lighting circuits containg key switches in say various rooms next to the light switch?

Hope this is clear.

I apologise if this is a basic question, but i would really like to get to grips with this.

Thanks

No, it isn't a basic question fella - there are some real mis-understandings out there.

Okay, the RIGHT way.

Emergency lighting starts and stops with an understanding of British Standard 5266.

Fundamental to any emergency lighting system is design, first and foremost - NOBODY should EVER install emergency lighting on the basis of "well any lighting is better than nothing" - that's utter rubbish, and is likely to get someone killed.

As far as the question you're asking goes, it is an utter myth that primary lighting should remain ON during a test.

The point of emergency lighting is that it operates upon failure of the primary lighting supply AND illuminates a clear path to exit the building - a fire exit route - at a minimum level of illumination of 1 lux down the centre of that escape route.

Now, if you wire emergency lighting separately from primary lighting, how is it ever going to know the local primary lighting has failed (e.g. the supply feeding the primary lighting has been interrupted). Bear in mind that emergency lighting should operate on the failure of LOCAL primary lighting - not lighting in general, and not, strictly, lighting NOT in the local area.

Key switches are simply switches, the same as any other switch. They contain a common and a switched terminal.

You can, therefore, do it in two ways - either a key switch per fitting (or number of fittings), or a "central switch" controlling the whole circuit.

The key switch simply interrupts the live feed in the same way as any other switch would.

However, for convenience, some sites do opt to have an emergency lighting test facility built in which does not interrupt primary lighting. This should be connected in one way only.

In this case, you need a dedicated live feed for your emergency lighting, separate from the primary lighting. However, it MUST be fed from the same MCB as the corresponding primary lighting. In this case, simply take the feed from the MCB to the key switch, and on the other side, the feed out to all your E/L fittings.

 

[sparkymoscow]

Thanks for that bill, can you do me a sketch diagram, could do with a visual aid just to clear things up.

Sketch of terminations of switch and key switch in a room

Sketch of Terminations of the 6 lighting feeds coming from 6 mcb,s into a 12 gang box with also 6 emergency feeds out to fittings from same 12 gang box.

Hope this is clear

Thanks for advice and sorry for bein a pain.

 

[IQ Electrical]

Surely on a circuit with maintained self-contained luminaries, the source of the circuit would not matter? (I'm on holiday without BS 5266)

 

[accordfire]

Surely on a circuit with maintained self-contained luminaries, the source of the circuit would not matter? (I'm on holiday without BS 5266)

Whether maintained or non-maintained, the fundamental principle is illumination on failure of the primary lighting.

Maintained lighting should be just that - primary when the supply is available, and switched automatically to emergency in failure.

Logically, it cannot be connected to anything other than the local circuit, as the same feed supplies both the primary and the emergency side.

However, from a design perspective, you must be certain it will operate upon failure of any other local lighting circuit too.

Within reason, you could theoretically supply it from any source, but, in practice, were you to feed it from another lighting circuit or a power circuit, for example, it may not illuminate at the correct time - and that may lead to problems if the primary lamp fails for any reason. If on the same circuit as other local lighting, it will, at least illuminate upon failure of the correct supply.

 

[accordfire]

Thanks for that bill, can you do me a sketch diagram, could do with a visual aid just to clear things up.

Sketch of terminations of switch and key switch in a room

Sketch of Terminations of the 6 lighting feeds coming from 6 mcb,s into a 12 gang box with also 6 emergency feeds out to fittings from same 12 gang box.

Hope this is clear

Thanks for advice and sorry for bein a pain.

Yes mate - will draw one out and scan it presently.

 

[accordfire]

Thanks for that bill, can you do me a sketch diagram, could do with a visual aid just to clear things up.

Sketch of terminations of switch and key switch in a room

Sketch of Terminations of the 6 lighting feeds coming from 6 mcb,s into a 12 gang box with also 6 emergency feeds out to fittings from same 12 gang box.

Hope this is clear

Thanks for advice and sorry for bein a pain.

Rough Diagrams, quickly knocked up - hope it gives what you want but if not, I can have another go tomorrow (less tired )

View attachment EL Schematics.pdf

 

[sparx24]

Thank heaven for 'accordfire-bill'!
there is so much B-S about this bs. talked on forums.
The point of emergency lighting is for when a local circuit fails, they come on/stay on. Not much good if fed from seperate /different circuit.
Key switches only required if turning off whole circuit causes safety issues, such as if no natural light or in areas used by vulnerable people.
Very good reply imho, thanks Bill.