How to check leakage and electricity theft with clamp ammeter
The clamp ammeter is a powerful tool for checking leakage or electricity theft on low-voltage lines.
Determine whether there is a problem with the residual current action protector itself
At the distribution transformer, disconnect the fuse on the phase line on the outlet side of the AC contactor that controls the low-voltage line. If the residual current action protector can operate normally at this time, it proves that the residual current action protector is good. Otherwise, the residual current action protector should be inspected and replaced.
Check to determine which phase wire is leaking
At the distribution transformer, disconnect the neutral line on the outlet side of the AC contactor that controls the low-voltage line, install the removed fuse core on one of the phases, and measure the phase with a clamp ammeter. The measured The current is the leakage current of that phase. In order to prevent the phase line grounding on the line (for example, someone uses the one-line-one-place method to steal electricity, etc.) to cause large current to damage the meter, first put the clamp ammeter in the high current gear when testing; if the detection value is very small, then Switch the clamp ammeter to milliamp detection.
After determining the phase line with leakage, determine the location of the leakage
At the distribution transformer, insert the fuse core into the phase line to be inspected, disconnect the neutral line and the fuses of the remaining two phases, and use a clamp ammeter on the pole to detect the live phase line to determine the location of the leakage. In the case of low-voltage line power transmission, a clamp ammeter can also be used to detect the low-voltage user connection lines within the suspected range. During detection, the phase line and neutral line of single-phase users should be placed in the jaws of the clamp ammeter at the same time, and the three phase lines and neutral lines of three-phase users should also be placed in the jaws of the clamp ammeter at the same time. If there is no leakage fault, the clamp ammeter indicates zero, otherwise it is not zero.
Check whether there is any leakage in the user's internal wiring and equipment
Use a clamp ammeter to measure the leakage current at the user's power entry line. At the same time, put the user's electrical equipment and lamps in and out one by one, and look at the clamp ammeter to detect changes in leakage current to find equipment with leakage. If all the equipment is good, or the equipment with leakage has been removed, but the clamp ammeter shows that the user still has leakage current, it may be that the user's low-voltage line has leakage, and it should be dealt with according to the specific situation.
