US Patent 10034340 Electrical lighting system power control

A network switch (5) for example a PoE switch, is operable to control supply of electrical power to individual luminaires (1,2) in a lighting network. The luminaires receive both electrical power for operation and signals to switch on and off through a common cable connection (9) such as an Ethernet connection. When switched on, each luminaire sends a signal repeatedly towards the Po E switch until switched off and the switch (5) supplies power to the luminaire while successive signals are received within a period less than a predetermined shut off period (Δ). In this way, power to the luminaire can be disconnected to avoid consumption of standby power when not in use.