- Reaction score
- 5,578
I have been asked to investigate a tripping RCD for a family member. I haven't been out to view yet and have asked very few questions but the scenario sounds like an RCD as a main switch. The homeowner opens all MCB's and then closes one by one until the RCD trips, finding that the 'lights in extension' is the culprit. He leaves this one open and the RCD does not trip. The trip has occured twice both times within the last week at times when it has been raining heavily.
No recent DIY/professional work has taken place
Trips spontaneously, i.e nothing is switched on at exact time of trip.
I will take a look on friday and I am happy about the steps to take if the fault is still there when I arrive as I can IR test and break down the circuit, but if the fault isn't there when I arrive I am not sure what to do apart from visually inspect as much as I can (especially any outside lights)?
I wasn't going to add this next bit as it shows my ignorance but am I right in thinking I should be looking for IR less than 0.008Mohm (very approx) which would be 30mA at 240V (so probably 0.01Mohm as will trip at less than 30mA). If the resistance is over that then it might be something plugged in (and disconnected at time of test).
I'm actually looking forward to it!! :smiley2:
No recent DIY/professional work has taken place
Trips spontaneously, i.e nothing is switched on at exact time of trip.
I will take a look on friday and I am happy about the steps to take if the fault is still there when I arrive as I can IR test and break down the circuit, but if the fault isn't there when I arrive I am not sure what to do apart from visually inspect as much as I can (especially any outside lights)?
I wasn't going to add this next bit as it shows my ignorance but am I right in thinking I should be looking for IR less than 0.008Mohm (very approx) which would be 30mA at 240V (so probably 0.01Mohm as will trip at less than 30mA). If the resistance is over that then it might be something plugged in (and disconnected at time of test).
I'm actually looking forward to it!! :smiley2: