How to detect short circuit or grounding
But I will answer the question based on how to detect whether the blade switch distribution line is short-circuited or grounded without the protection of a circuit breaker and leakage circuit breaker; (actually, if there is a short circuit on the blade switch distribution line; the consequences Either the wire is burned out or the blade switch is burned out, nevertheless; I will still answer the question based on the detection principle).
(1) Turn off the power switch at the beginning of the distribution line, disconnect all load switches on the line, and separate the plugged loads plugged into the socket. Use a multimeter resistance × 100 scale to measure the resistance of the two outgoing wires at the outlet of the power switch. Resistance. If the resistance of the multimeter is very small (that is, the pointer swings almost to the right), it proves that there is a short circuit between the phase line and the neutral line. Otherwise, there is no short circuit. The same detection method is used to measure whether there is a short circuit between the phase line pair protective ground (zero) line and the neutral line pair protective ground (zero) line.
(2) If there is no short circuit between the phase line to the neutral line, the phase line to the protective ground (zero) line, and the neutral line to the protective ground (zero) line, you can detect whether the phase line and the neutral line are grounded.
Detecting Ground If you have a clamp meter on hand, it is best to use a clamp meter to detect the ground current. The detection method is: first turn off the power switch, remove the distribution neutral wire from the outlet of the power switch (and mark it), then close the power switch, and use a clamp meter to measure whether there is ground current in the phase wire (clamp meter). First set the meter to the 100A level, if no current is detected, and then slowly set the meter to a smaller current level.) If the grounding current is still not measured, then the phase line grounding can be ruled out. After testing the phase wire, turn off the power switch and remove the phase wire, connect the neutral wire to the phase wire outlet contact of the power switch, close the power switch and use the above method of measuring the phase wire with a clamp meter to detect the neutral wire.
If you don't have a clamp meter on hand, you can also find a chandelier head and an incandescent bulb of about 25 watts, install the lamp head, and connect two wires of about 15 cm for backup. The detection method is: turn off the power switch, remove the phase wire and neutral wire, first connect the lamp holder and the bulb in series between the phase wire and the phase wire outlet contact of the power switch, take safety measures and then close the power switch. If the bulb lights up, it proves that the phase wire is grounded. The higher the brightness of the bulb, the greater the ground current will be. On the contrary, the smaller the ground current will be. If the bulb does not light up, it can be ruled out that the phase wire is grounded. After testing the phase wire, turn off the power switch, remove the phase wire, and connect the original light bulb in series between the neutral wire and the phase wire connection point at the outlet of the power switch. After taking safety measures, close the power switch for testing. The detection result of the neutral line is also the same as the above-mentioned detection phase line.
