How to find a fault in the lighting cable using a multimeter
Once the lighting line leakage phenomenon, not only waste of electricity, but also may cause electric shock accident. Leakage and short-circuit nature of the same, just the degree of development of the accident is different, serious leakage may cause a short circuit. Therefore, the lighting line leakage, must not be taken lightly, should always check the insulation of the line, especially when the leakage phenomenon is found, it should be timely to identify the causes, to find out the point of failure, and be eliminated.
Lighting line leakage is the main reason: a wire or electrical equipment insulation is damaged by external forces; the second is the line by the long-term operation, resulting in insulation aging and deterioration; the third is the line by the moisture invasion or pollution, resulting in poor insulation.
First of all, determine whether the leakage is indeed. Available pointer multimeter R × 10k file measurement of the size of the insulation resistance, or digital multimeter placed in the AC current file (at this time is equivalent to an ammeter), connected in series on the main switch, turn on all the switches, remove all loads (including light bulbs). If there is a current, then the existence of leakage phenomenon. Determine the line leakage, you can continue to check according to the following steps.
1, determine whether the phase line and the zero line leakage, or phase line and earth leakage, or both. Method is to cut off the zero line, if the ammeter indication is unchanged, it is the phase line and the earth leakage; if the ammeter indication is zero, it is between the phase line and the zero line leakage; ammeter indication is smaller but not zero, it is between the phase line and the zero line, phase line and the earth are leakage.
2, to determine the scope of leakage. Remove the circuit fuse or pull the circuit breaker, if the ammeter indication is unchanged, then the bus leakage; ammeter indication is zero, then the branch leakage; ammeter indication becomes smaller but not zero, it is shown to be the bus, the branch are leakage.
3, find out the leakage point. After the above checks, and then sequentially disconnect the line lamps and lanterns switch, when disconnecting a switch, the ammeter indicator back to zero, then the branch line leakage; if small, then this branch line leakage, there are other leakage; if all the lamps and lanterns switch off, the ammeter indicator is unchanged, then the section of the trunk line leakage. Sequentially narrow the scope of the accident, you can further check the section of the line joints, and wires through the wall and other places whether the leakage. After finding the leakage point, the leakage fault should be eliminated in a timely manner. Load end begins to detect the front end step by step, to see whether the work is caused by the line or the components caused by the work, it can be judged. After eliminating the short-circuit fault point, load and connect the qualified fuse and then send power.
