Maintained emergency lighting (self-contained)

[TickityBoo]

While it is essential that non-maintained lighting must be connected directly to existing local lighting sub-circuits to ensure operation in the event of a loss of power to a lighting sub-circuit, is it necessary (or normal practice) for maintained lighting to be wired to the existing lighting circuit? Can they be set up on their own circuit? If on their own circuit, they would continue to operate from the mains if a local lighting sub-circuit was to fail and would run off the batteries if their own circuit was to lose power / general power failure occurred.  

What is the preferred option - a dedicated circuit or wired to the existing circuit? My thinking is that a dedicated circuit is better for maintenance reasons.  I take it a switch to turn off maintained lights when the building is unoccupied is achievable in either set up?  However, grateful for views.

[Mushy]

Check this out

http://dynalite-online.com/tech_docs/tech_guides/Technical%20Guide%20-%20Emergency%20Lighting.pdf

[Wiz]

I assume we are talking about self-contained units. It seems to me that your proposal provides for 230v ac supplies being taken from different points on the distribution circuit ( a local lighting circuit and a specially provided emergency lighting mains supply) I'd be interested in reading what the electricians on Firenet make of this i.e sharing a neutral for supplies from different points, and the possibility of ending up with supplies from different phases at the same fitting.

[Galeon]

It getting a to be a nightmare on sites at the moment , with arty farty down-lighters made in slovakia absolutely useless , general lighting circuits being overloaded , we regularly play spot the emergency.
The local lighting circuit is in place for emergencies for good reasons , however when some pleb has thrown in a bit of twin and earth with no means of isolation to the fitting , thats when it goes wrong.
Then there's the school of turn the breaker off and we are all plunged into an abyss.
I don't see a real problem with emergency lighting on separate circuits , in relation to the 3 phase element , you can always use a phase monitoring relay.
I think the local way we do it now is the best , however its abused.