at the end of the garden, about 40m from the house, is a pond. In the pond is a 320W pump that pumps water up to the top of the garden (4m head) which then runs down a stream to the bottom pond again.
From the CU at the house, the supply runs via a RCD through a buried armoured cable to a shed at the end of the garden. There, it goes through a second RCD which feeds two MCBs; one supplying the shed lights and the other the shed sockets plus, via a fused switch, an outdoor switch bank.
The outdoor switches (triple) feed an outside light, outside socket and the pond pump.
Recently the RCD up at the house tripped. It wouldn’t reset so I had to leave it like that for a few hours. When I had another look, it reset no problem. Everything ran ok then three days later, same happened. Again, after a ‘rest’ it took the reset.
It’s done this a few times now and the only thing that’s been drawing power on that circuit has been the pump. Yet the pump runs perfectly for days between trips (we run it constantly) so I’m not convinced the pump is faulty. I cleaned it out and the impeller was only replaced 18 months ago, and the pump motor is all sealed. If water got into the windings, would it show this sort of tripping pattern? I’d expect it’d trip and that would be that.
The only variation was the second time it happened, when the RCD in the shed tripped, rather than the one at the house end of the circuit. That suggests it’s not a faulty RCD.
It tripped just now, as I was typing this, after running fine since Saturday morning!
From the CU at the house, the supply runs via a RCD through a buried armoured cable to a shed at the end of the garden. There, it goes through a second RCD which feeds two MCBs; one supplying the shed lights and the other the shed sockets plus, via a fused switch, an outdoor switch bank.
The outdoor switches (triple) feed an outside light, outside socket and the pond pump.
Recently the RCD up at the house tripped. It wouldn’t reset so I had to leave it like that for a few hours. When I had another look, it reset no problem. Everything ran ok then three days later, same happened. Again, after a ‘rest’ it took the reset.
It’s done this a few times now and the only thing that’s been drawing power on that circuit has been the pump. Yet the pump runs perfectly for days between trips (we run it constantly) so I’m not convinced the pump is faulty. I cleaned it out and the impeller was only replaced 18 months ago, and the pump motor is all sealed. If water got into the windings, would it show this sort of tripping pattern? I’d expect it’d trip and that would be that.
The only variation was the second time it happened, when the RCD in the shed tripped, rather than the one at the house end of the circuit. That suggests it’s not a faulty RCD.
It tripped just now, as I was typing this, after running fine since Saturday morning!
