Why the 30mA RCD tripping with a circuit connected to a timer.

Question

its in a hotel. we are experiencing tripping of RCD on the external lighting circuit when timer is automatically actuated. if it was a permanent fault on the circuit, when i would be reseting the RCD, it shall be ripping again but no, it runs the whhole nite. even i have force the timer manually, it doesn't trip the RCD. the problem is actually is when the timer is actuated automatically, then the rcd is tripping. moreover not only one panel in the hotel is experiencing the problem, but all the sub distribution panel is going through. our timer is programed at 6 pm and some 6 15. when the time is reach, 'tack', all rcd trips, but when reset, wow it runs the whole nite. please help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!...

do you think its related to the timer waveform and conflict with RCD. please help budddies

Answer 1

Yes, definitley a problem with the timer motor. If there was anything wrong with the circuits you would never reset the RCD. If it was something to do with the surge of current to the external lighting, it would trip when you operated it in manual. There has to be some sort of conflict between the timer motor and the RCD. Change the timer for a different type.