ELs Not On Local Circuit

[Guest Jim]

Im working at an old property  (a small res. home for adults with learning disabilities) and have realised that some of the emergency lighting is not linked to the relevant local lighting circuit. That is, if said light circuit were to trip, then ELs in that area would not illuminate as they are still receiving mains power (all ELs are self contained, non maintained). They would obv. light in the event of a full power cut. The arrangement will have been in place for around 20years. Checking the wiring at the board there's no quick fix possible. To sort would involve a fair amount of work and inconvenience.Is there a reg that requires the present arrangement has to be remedied? Or is it one of those less than ideal situations that can be lived with? Thanks

[Tom Sutton]

It doesn't matter how the luminaires are lit, either by mains or battery providing the emergency escape route is illuminated and people can find there way out of the premises safely. In a building with a number of sub circuits, and in the event of a fire affecting one sub circuit only the emergency luminaries in that circuit will light, the remainder in the building will be lit by the mains. In the event of a fire affecting the main intake all the emergency luminaries will operate and the occupants of the premises will be able to evacuate safely.

What I do not understand you said "if said light circuit were to trip, then ELs in that area would not illuminate as they are still receiving mains power" but if the circuit tripped then where would the mains power be coming from? The bottom line is in the event of of a fire affecting any circuits will the emergency escape route be illuminated sufficiently for people to escape safely. 

Edited October 21, 2015 by Tom Sutton

[AnthonyB]

Emergency Lighting should be installed off local lighting circuits otherwise it will not operate if there is a partial loss of lighting in the premises.

It is not uncommon however to find that less than competent installers at some time in the history of a premises have put EL on a dedicated circuit (getting mixed up with fire alarm power supply requirements) instead of the local lighting circuit.

Rewiring is often not feasible, so the easiest way of making the system compliant is to replace the non maintained fittings on the dedicated circuit with maintained fittings that are always lit. The running costs of such a change are negligible if you use LED fittings.