Hi.
I got hold of an earth leakage clamp and took it home to my flat to measure things as a matter of interest after using it at work.
I got some strange readings though.
I made a breakout plug and socket with the lead connecting them having the earth wire taken outside the sheath so that I can clamp onto just the line and neutral. Whatever I got on the line/neutral I also got on the earth so at least that was consistent.
It was interesting to note that there is quite a bit of circulating current flowing through all the pipework. I measured 5mA at one of the radiators. Even with the main switch off there was 2mA.
Anyway, the following readings were taken first from the items of equipment, then from the CU tails. The earthing conductor was slightly different so I didn't take the reading from there as there would be parallel earth paths, so more accurate from the tails.
3kW kettle. 0.03mA Tails 4mA
Martindale 7mA Tails 4mA
2 core flex of pendant with retrofit LED lamp. 0mA Tails 0.05mA
I was expecting that maybe there would be some very slight difference but not this much.
The one at the light fitting is confusing as there is no earth connection. All I can theorise is that the current flow is setting up an earth leakage in the installation wiring. But that is not consistent with the other 2 readings as the kettle is so much higher and the Martindale the opposite way round. I also expected to see a much higher reading taken at the kettle itself as it has an MI heating element known for it's high leakage.
Anyone have any thoughts on this?
