Switching emergency lighting from the normal lighting switch is quite tricky but I once did it by having the normal lighting switch close to energise a N/C relay that turned the lights off, one pole for normal, one pole for the emergency lights. This meant that when the switch opened or when the normal supply failed, the relay would close and the emergency lights came on.
Switching emergency lighting from the normal lighting switch is quite tricky but I once did it by having the normal lighting switch close to energise a N/C relay that turned the lights off, one pole for normal, one pole for the emergency lights. This meant that when the switch opened or when the normal supply failed, the relay would close and the emergency lights came on.
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