I found a T&E sticking out of an external wall wrapped in electrical tape. I got no reading from it, but after flicking a light switch on the wall inside it read 240V. I assumed it must have been an outside light at some point so I installed an IP54 outside light. It's not a PIR light, just a simple one controlled by the switch and is permanently turned off.
It worked fine for a few weeks but then it rained recently and tripped the MCB. The RCD did not trip, just one MCB which is only connected to the outside light an one other room.
I checked the light a there's no water in it, it's water tight. It's been rainy and damp for 2 days now and the MCB trips every time I reset it. In the end I removed the outside light, taped up the cable and tucked it under the eaves. The MCB is fine now.
Any ideas what's going on? Can MCB's trip purely from humidity even if there's no actual water ingress?
It worked fine for a few weeks but then it rained recently and tripped the MCB. The RCD did not trip, just one MCB which is only connected to the outside light an one other room.
I checked the light a there's no water in it, it's water tight. It's been rainy and damp for 2 days now and the MCB trips every time I reset it. In the end I removed the outside light, taped up the cable and tucked it under the eaves. The MCB is fine now.
Any ideas what's going on? Can MCB's trip purely from humidity even if there's no actual water ingress?