Investigative Methods for Anti-Theft of Electricity (2)

2. Check the wiring

Mainly visually check whether the wiring of the metering current loop and the voltage loop is correct and intact. For example, whether there is an open circuit or a short circuit, whether there is any change or wrong connection, it should also be checked whether there is any wiring around the meter or privately pulled random connections, and whether the secondary circuit wires meet the requirements, etc.

(1) Check the wiring for open circuits or poor contact.

A. Check whether the second voltage line is open, especially pay attention to whether it is tightened and whether the contact surface is oxidized.

B. Check all wiring terminals, including electricity meters, terminal blocks, secondary voltage, and current wiring terminals, etc. The mechanical fixation of the joint should be good, and the metal conductor should be in reliable contact to prevent the virtual connection or false connection caused by the oxide layer or insulating material.

C. Check the core of the insulated wire, and pay attention to the open circuit or non-connection fault caused by deliberately breaking the core. For example, when some single-phase users use the undervoltage method to steal electricity, they intentionally break the core of the neutral line, which causes the meter to fail to measure normally.

(2) Check the wiring for a short circuit.

A. It mainly depends on whether there is a U-shaped short-circuit wire in the inlet hole of the meter, and whether there is a short-circuit in the junction box.

B. Check the meter connected through the transformer. In addition to checking the incoming line of the meter, you should also check whether the secondary or primary of the transformer is short-circuited and whether the second line between the second terminal and the meter is short-circuited. In particular, pay attention to check whether there is a short circuit in the wiring of the intermediate terminal block and the insulation layer of the secondary wire is damaged.

(3) Check whether the wiring is changed or wrongly connected. Reconnection means that the wiring of the original metering circuit has been changed, and wrong connection means that the wiring of the metering circuit does not meet the normal metering requirements. For low-voltage users who do not pass through the transformer during inspection, the simple wiring of the meter can be intuitively judged by experience, and the metering circuit connected through the transformer can be checked against the wiring diagram. A detailed inspection is usually also determined using meter measurements.

(4) Check whether there is over-meter wiring and privately pulling random connections.

A. For high supply and low meter users, pay attention to whether there is a bypass connection before the low-voltage outlet end of the distribution transformer is connected to the metering device. For ordinary low-voltage users, it is necessary to pay attention to check whether there is bypass wiring in the hidden places such as the wire before entering the meter, such as against the wall, cross, etc., and also pay attention to check whether there is abnormal wiring between neighboring households.

B. Check the unauthorized connection, which refers to those who use electricity on the lines of the power supply department without reporting to the household.

(5) Check whether the wiring meets the requirements.

A. Whether the conductor cross-section of the secondary circuit of the voltage and current lines meets the requirements of ≥2.5MM2.

B. Whether the measurement secondary circuit is relatively independent, and if there are other series loads, whether the total secondary impedance is too large.

C. Check whether the secondary line is too long and if there are other parallel loads, whether the secondary load is too heavy.