Emergency lights - maintained vs non-maintained

[Paul_Thomas]

What's the difference between maintained and non-maintained emergency lights? (May be a stupid question!)

For example on here http://www.toolstation.com/index.html?code=95784

[luminaire]

The non-maintained lights will only come on in the event of a power failure.
The maintained lights you can also use as normal.

[Paul_Thomas]

Aaah!

Makes sense, although using the term 'maintained' for it doesn't!!

[Steve]

Does that mean "sustained" EMs are on permenantly?

[Spark123]

Sustained lights have two lamps, basically a normal lamp and a non-maintained emergency light.
The normal lamp can be switched, very similar concept to a maintained unit but the maintained unit only having the single lamp for both duties.

[Steve]

what about the exit signs in our shop then, which are permenantly lit? what are they called?

[Spark123]

How many lamps in them?
Probably maintained, with a wire loop between L and Ls.
That is assuming they are self contained (have their own battery pack in them).