Emergency Lighting Generators.

[Tom Sutton]

Re BS5266-1:2005 Would the fact that we have a generator to power all amenaties should we suffer a power failure, that kicks in within seconds cover us for the emergency lighting.

I would imagine the answer is yes providing it conforms to the above standard an kicks in between 5 and 15 secs but I would like it confimed. Please 

[Davo]

Hi Tom

As you know, there are different types of EL eg escape or for machinery etc
So it would depend on what the premises are used for imo.

In a factory with lathes etc my answer would be no, in an office then perhaps

The problem with gennys is that you have to test them on load, maintenance etc, so EEL might be cheaper in the long run.

davo

[kurnal]

Will it be sensitive to lighting sub circuit failure? How are the lighting circuits subdivided? Whilst your description works for full mains failure if a primary lighting MCB trips because of a fire will key areas be left in darkness? There is a difference between emergency lighting and escape lighting.

[colin todd]

Big Al.

Escape lighting is a form of emergency lighting. What I think you meant to say is that there is a distinction between escape lighting and standy lighting.

[kurnal]

Thanks Col. Thats probably what I meant. Love the irony though.

[Phoenix]

Re BS5266-1:2005 Would the fact that we have a generator to power all amenaties should we suffer a power failure, that kicks in within seconds cover us for the emergency lighting.

I would imagine the answer is yes providing it conforms to the above standard an kicks in between 5 and 15 secs but I would like it confimed. Please 

Many premises have areas where it would not be safe for people to be plunged into darkness for 15 seconds, eg factories, hospitals, kitchens and what about staircases.  Because of that and because the generators don't usually kick in at all if it is only the lighting circuit that fails, it is normally important that conventional emergency lighting of some sort is provided in addition to the cover provided by the generator. 

Having said that, it may be possible to relax on the conventional emergency lighting in less critical areas.

Stu

[Tom Sutton]

My posting was based on BS 5266, see below, but I imagine it would be very unlikely to meet the standards therefore it needs surveying by a competent person and I suspect the outcome would be the provision of a separate emergency escape route lighting system.

4.6 Standby lighting
If standby lighting is used to provide emergency escape lighting, the installation shall comply with the provisions of this standard and the appropriate product and wiring standards.

4.2.6 Response time: The emergency lighting detailed in this code should be provided within 5 s of the failure of the normal lighting supply, but at the discretion of the enforcing authority this period can be extended to a maximum of 15 s in premises likely to be occupied for the most part by persons who are familiar with them and the escape routes.

[AnthonyB]

In my experience emergency generators are used a business continuity measure providing standby lighting, essential services power and IT (to back up local UPS to servers that has a quicker changeover) and that escape routes and high hazard task areas still have self contained battery fittings (NM or M as required) on local circuits for escape/safety purposes.

In other words, I echo the above posts!

[lyledunn]

Problem is that the generator will probably feed in to the same circuits as the normal supply. Thus a fault that took out the normal supply might also take out the gen. If on the other hand the gen supplies slave luminaires then the circuits would have to be of appropriate fire resistance, mims, fire tuff or the like.

[CivvyFSO]

It's all very good until a fire burns through a main lighting cable, taking the lighting out without taking the power supply out. Hey presto - Complete darkness.

Might as well go the whole hog and accept the fire as a light source under risk assessment. 

[AnthonyB]

Well indeed - and the same can be said for some central battery systems, although both can monitor local circuits for failure as well if correctly set up.

If it's a slow starting generator (> 5 seconds) you need separate emergency lighting anyway.

All of which is why you don't see many generator only EL systems.