On a small public house that has no emergency lighting: I wish to install such lighting. The pub is 150 years old and consists of three smallish rooms.It also has a corridor leading to an exit and two toilets. It has a flat up#stairs for the publican. When I talk to contractors that are all 'thinking big'  involving lifting the flooring in the flat and laying new cable from the main fuse box. The other choice is using ducting but this is not appropriate in such an old pub.

As an example I can see an emergency light is required in the corridor as it has no windows. It already is served by a switched flush fitting light. What I cannot understand is why I cannot replace the existing fitting with a unit with its own battery charging from the existing light source. If necessary one could remove the switch from the circuit and use a LED fitting and leave it on 24/7. This would be much cheaper than rewiring the whole pub which in reality would effectively close the pub for good.

 

Please help 

A brief summary of requirements is here http://www.hochikieurope.com/ckfinder/userfiles/files/BS5266 Guide Booklet - ISS6 - MAY14 (email)(1).pdf 

The standard was updated since this was produced, but the basic principles apply.

Emergency lighting should operate on local lighting circuit failure so anyone saying you should have a new dedicated circuit is unlikely to be competent in emergency lighting design and may not be the contractor to be used. On some rare occasions you can't use a local lighting circuit but where a dedicated circuit is used it must use maintained (always lit) fittings

You have two options - separate dedicated EL fittings wired into the existing lighting circuit, or easier (but more costly per unit) replace your normal light fitting with a combination unit - which works like a normal light fitting but includes a battery pack to provide back up supply (you would usually need both a permanent and switchable live to the fitting for this to work)