How to use a multimeter to detect a short circuit in a line
(1) first power off, the multimeter function switch to the buzzer gear, the multimeter two pens on the two terminals to be measured bai test, if the short circuit will have a beep, and shows a very small on voltage value, this time between the two points to be measured short circuit.
(2) using a multimeter to measure the line insulation can know whether the line is short-circuited. For example, measuring single-phase ground insulation, if the insulation value is zero (metallic grounding) or very low (non-metallic grounding), you can judge this phase of the line grounded. If it is not grounded, the insulation value is high. Then measure the insulation between phases, if the insulation between phases is zero, it means that this two-phase line is a short circuit between.
(3) to ensure that there is no electricity in the line, the resistance file (pointer meter put RX10 file, digital meter will call the on and off file), the two meter stick contact to measure the two points (or two lines), the pointer meter does not move is a circuit breaker, the fullness of the dump over is a short-circuit; digital meter circuit breaker digital no change, and no sound, short circuit will call, or the number of zeros.
(4) will be separated from the two ends of the wire core, do not touch each other, and then the multimeter hit and above the position, the pen were hitched to the two different colours of the line, if the measured value is above 0.5 megohm, or show infinity, then the insulation of the line is not a problem, that is, the line does not exist leakage; if the measured value of the results is 0.5 megohm or less, then the line insulation is unqualified If the measurement result is below 0.5 megohm, then the line insulation is not qualified, and there is leakage. Find all the joints and junction boxes in the line after this air open, whether the joint insulation is not good, and then resistance measurement method at each joint and junction box with a multimeter check. The reason is that the short-circuit moment generates a high current air open automatically tripped, the line will not burn out how much general situation in the joints or junction boxes to resistance measurement method is able to determine the location of the short circuit.
