Check for electricity theft and leakage with a clamp meter
The clamp ammeter is the most practical electrical tool for measuring low-voltage lines, with high accuracy and good stability, which are its main characteristics. Electric power workers can be used to detect low-voltage current, micro current, and check equipment leakage, testing whether the main circuit is stealing electricity. This article introduces the detection of electricity theft and leakage using a clamp ammeter
Check for leakage inside the circuit and equipment
Measure the leakage current on the main circuit using a clamp ammeter, and then turn off the electrical equipment in sequence. For each shutdown, use a clamp ammeter to detect changes in the leakage current of the circuit and identify the leaking equipment. If all electrical equipment has been turned off, but the clamp ammeter still shows leakage current, it should be due to leakage in the low-voltage line. The line should be replaced or the leakage point should be detected
Determine which phase line has leakage
At the distribution transformer, disconnect the neutral wire on the output side of the low-voltage line contactor, remove the fuse and install it on one of the phase lines. Measure the phase with a clamp ammeter, and the measured current is the leakage current of that phase. Test the leakage current of other phase lines in sequence
Determine the location of leakage
When the low-voltage line is energized, the single-phase and neutral wires should be placed in the clamp of the clamp ammeter at the same time during detection, and the three-phase three phase wires and neutral wires should also be placed in the clamp at the same time. If there is no leakage fault, the phasor sum of the load current magnetic flux is zero, and the clamp ammeter indication is also zero; If there is leakage current, the clamp ammeter can detect the leakage current.
matters needing attention:
When searching for leakage faults, pay attention to safety and maintain a safe distance between the human body and live parts.
Clamp the live wire and zero wire together to measure the leakage current of electrical equipment. (Note 2 pieces)
Clamp the ground wire to measure the leakage current of the electrical equipment's grounding wire. (Attention should be paid to individual pieces)
Clamp the three-phase and four wires together to test the total leakage current. (Note 4 pieces)
Clamp the main line and measure the current of the main line. (Attention should be paid to individual pieces)
