How to detect short circuit in household circuits? It is very simple to use a multimeter to detect short circuit in electrical appliances.
When there is a short circuit problem in a household circuit, the electrical appliance will trip as soon as it is running. Unless the short circuit point is found and the fault is eliminated, the circuit will be normal. Here is a simple method for detecting a short circuit in an electrical appliance with a multimeter. Let's take a look.
1. Multimeter detects short circuit
Use the multimeter resistance setting to measure the resistance value between the lines, disconnect the power supply, and disconnect all loads in the circuit, including light bulbs, TVs, washing machines, refrigerators, etc. Use the multimeter resistance 1 ohm setting to measure the live and neutral wires. If the meter needle moves the scale More than 1/3 indicates a short circuit.
2. Decompose the circuit in turn
First break down the wiring, and then use a multimeter to check whether there is a short circuit in the home circuit.
Detection method: Untie the wires in the middle of the line at home, and measure the front half circuit and the back half circuit respectively to divide the possible locations of the short circuit, see if the short circuit is in the front or rear, and then untie it in sequence. Check part of the circuit step by step until the fault location of the short circuit is found.
3. Simple method to detect short circuit
Put the multimeter to the point where the mark looks like a "month" with one less horizontal line. When the buzzer beeps, it means a short circuit. If there is no sound, it means the line is normal.
In addition, you can also set the meter to the resistance position. When the resistance value pops up, it means there is a short circuit in the line. If the displayed value is 1, it means there is no short circuit.
How to find short circuit fault points
After finding the short-circuit fault branch, you need to continue to determine the specific location of the fault point. The short-circuit fault point must be at both ends or inside the voltage-reducing components in the circuit (such as light bulbs, voltage coils, motor windings, resistors and other loads).
The method to find the short-circuit fault point of this circuit is: disconnect one end of the voltage-reducing component R (the light bulb in the picture), and use a multimeter to electrically measure the resistance between 1 and 2 (that is, both ends of the voltage-reducing component). If the resistance is zero, it means that the short-circuit point is inside the load; if the resistance is a certain value, it means that the inside of the load is intact and the short-circuit point is outside the load device. If the short circuit point is external, then measure the resistance between points 1-3. If the resistance value is zero, the short circuit fault is between wire 3# and wire 1#.
By disconnecting certain points of these line segments and measuring them in sequence, you can find the identified short-circuit fault point.
