Harry Macdonald:
I would have thought that the farmer might receive quite an interesting electricity bill if he had anything approaching 45A continuously going from Live to Earth.
Harry don’t forget, this is a TT installation. I measured Ra with a loop tester at 80ohms. That would have included Re but not any parallel contribution due to the metal stanchions of the old barn. The combined resistance was 26 ohms. As AJ indicated, the combined consumer resistance will have been lower than Re to see that sort of voltage division; 187v across Re and circa 230-187 across the consumer connection to earth. There appeared to be about 1ohm in the fault but all in all a little over 8A of fault current.
To be honest, I am sorry that I didn’t spend more time on it as it was a very interesting situation. I am almost tempted to return and re-impose the fault, if nothing else to get a photo of the MFT displaying 187v with one probe on the water tap and the other on the re-bar in the flower bed! Might even have stuck a lamp on for effect!
Harry Macdonald:
I would have thought that the farmer might receive quite an interesting electricity bill if he had anything approaching 45A continuously going from Live to Earth.
Harry don’t forget, this is a TT installation. I measured Ra with a loop tester at 80ohms. That would have included Re but not any parallel contribution due to the metal stanchions of the old barn. The combined resistance was 26 ohms. As AJ indicated, the combined consumer resistance will have been lower than Re to see that sort of voltage division; 187v across Re and circa 230-187 across the consumer connection to earth. There appeared to be about 1ohm in the fault but all in all a little over 8A of fault current.
To be honest, I am sorry that I didn’t spend more time on it as it was a very interesting situation. I am almost tempted to return and re-impose the fault, if nothing else to get a photo of the MFT displaying 187v with one probe on the water tap and the other on the re-bar in the flower bed! Might even have stuck a lamp on for effect!
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