Vladimir Georgiev Mar 29, 2011:

well, sorry to break the consensus... the term, it seems, refers to lighting that routinely used for a specific purpose (to light a store, to light emergency signs when dark, to light the city streets) and is usually automatically turned on/off depending on the controller settings for a certain period of time; (i.e. it is the opposite of emergency lighting, which is switched on during 'extraordinary' events only).

Rafal Piotrowski Mar 28, 2011:

"Safety/back-up lighting" are AT LEAST as good. I suggest that the agreers should submit their own versions, as they might fit the context even better. And then let the Asker decide :)

Rafal Piotrowski Mar 28, 2011:

Actually, I based my hint on a pair of similar Polish words, namely :"dyżurne" & "oświetlenie". They do not form a standard cliché, but separately they mean the same as in Bulgarian. "Dyżurny" means "on duty", "to be there just in case". "Emergency" seemed a natural conclusion. HTH :-)