S
Spearmint
Had the DNO out last week to remove old three phase overhead lines to a property undergoing refurbishment as they were sagging really low (within 2m from the ground!), had been for years and the new owner didn't like the look of them! Anyway the DNO agreed to remove and joint a new underground supply from the existing pole to a new location at the other end of the property. After all the work was done they mentioned that they dropped the fuses from 80A to 60A due to high EFLI.
Firm I work for only have Metrel MFTs, can't remember model off top of my head but all the same model. Went to test the new board before energising and I'm getting a Ze of 0.44... on a TN-C-S. Now these MFTs can only do no trip, and I'm aware of that higher readings no trip can give but the only way of getting a lower reading is to reduce the test current. Reducing to 30ma for example gives 0.34, even that's not ideal! I feel uncomfortable with these readings but we don't have a high current tester.
So... should I push for a new tester to verify the reading or just recommend getting the DNO out?
Firm I work for only have Metrel MFTs, can't remember model off top of my head but all the same model. Went to test the new board before energising and I'm getting a Ze of 0.44... on a TN-C-S. Now these MFTs can only do no trip, and I'm aware of that higher readings no trip can give but the only way of getting a lower reading is to reduce the test current. Reducing to 30ma for example gives 0.34, even that's not ideal! I feel uncomfortable with these readings but we don't have a high current tester.
So... should I push for a new tester to verify the reading or just recommend getting the DNO out?