The 4 types of emergency ECGs
Four types of self-contained emergency devices: type A, B, C or D
The control gear can be only one of these types
Type D: Non-maintained: the lamp is only on when the mains is not present (or in test mode)
Type C: Maintained: the lamp is always on, whether the mains is present or not
Type B: Switched-maintained non-dimmable: the lamp can be switched on or off when mains is
present, but is on when the mains is not present
Type A: Switched-maintained dimmable: the lamp can be dimmed or switched off when mains is
present, but is on when the mains is not present