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There are two basic types of emergency lighting luminaires - maintained and non-maintained.
Maintained, these luminaires have the advantage of being able to be switched between the maintained function (lamp illuminated at all times) and non-maintained (lamp off until power supply fails), making them ideal for applications such as corridors, workshops and permanently illuminated emergency exit signs. The maintained luminaires also have the facility of being switched in banks of up to ten units.

Non-maintained, these luminaires are only illuminated on a failure of the mains supply. Ideal for emergency exits, switchrooms and storage areas.