The standby emergency facility gives up to 6 hours back up light following loss of power. This gives the option to combine improved safety with a system that is cost effective and very beneficial to the environment. Such characteristics are particularly important for offices, corridors stairwells where lights are frequently used and often inaccessible. The controllable emergency light facilities give a safer environment. On installation the brightness of the emergency light can be set to deliver a brighter light or a longer life to meet individual preferences.