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Being doing a domestic bathroom refurb', lighting, altering shower circuit (have a Megger 1730 MFT).
History, property has no RCD protection, but as it was a Hager CU, had contemplating using RCBO's (TN-C-S supply). Before doing any work, I decided to clamp the meter tails, as the property has only 1 x RFC. Did so with tv etc on, fridge freezer running, appliances turned on but not running, lights turned on. Got a reading of above 30mA. Suspecting my cheapo earth leakage clamp meter was at fault (although gave normal readings at my house, previously), got a ex' lead out with exposed earth. TV gave the highest reading of 3mA. Went back and clamped tails again, got reading of 9mA.
Yesterday, altered bathroom lighting, did initial tests, all okay (IR L/N to earth 350). Today, altered existing shower circuit for new shower pump. All tests fine (IR 3 x >999), till I got to Zs. MFT was making audible warning tone (which I had with high touch voltages) and displaying <> PE above indicated voltage. MFT completed Zs test (0.16ohms & 1.24kA) and audible tone returned. Contacted Megger, who suggested Ze test at CU. Ze test completed, but same audible tone (0.12ohms & 1.90kA). Also did PFC/PSC and got similar results with 0.11ohms & 2.14kA. There is a supply transformer across the road.
Megger range me back, never seen fault code before, but suggested it could be touch voltage on circuit, or faulty tester.
Anyone experienced this before?
History, property has no RCD protection, but as it was a Hager CU, had contemplating using RCBO's (TN-C-S supply). Before doing any work, I decided to clamp the meter tails, as the property has only 1 x RFC. Did so with tv etc on, fridge freezer running, appliances turned on but not running, lights turned on. Got a reading of above 30mA. Suspecting my cheapo earth leakage clamp meter was at fault (although gave normal readings at my house, previously), got a ex' lead out with exposed earth. TV gave the highest reading of 3mA. Went back and clamped tails again, got reading of 9mA.
Yesterday, altered bathroom lighting, did initial tests, all okay (IR L/N to earth 350). Today, altered existing shower circuit for new shower pump. All tests fine (IR 3 x >999), till I got to Zs. MFT was making audible warning tone (which I had with high touch voltages) and displaying <> PE above indicated voltage. MFT completed Zs test (0.16ohms & 1.24kA) and audible tone returned. Contacted Megger, who suggested Ze test at CU. Ze test completed, but same audible tone (0.12ohms & 1.90kA). Also did PFC/PSC and got similar results with 0.11ohms & 2.14kA. There is a supply transformer across the road.
Megger range me back, never seen fault code before, but suggested it could be touch voltage on circuit, or faulty tester.
Anyone experienced this before?