Types of emergency lights

For UK and Australian regulations, two types are distinguished:

Maintained luminaires are permanently illuminated, and remain illuminated when power fails. They are used for tasks such as emergency exit lighting. In some cases they may be switched off deliberately, but are usually required to be active when a building is occupied, or when the public are admitted, such as for a theatre.

Sustained or non-maintained luminaires may be switched on and off normally. If the power fails, they turn on automatically.