How to measure leakage current with a multimeter
The multimeter can not only measure the voltage but also the leakage current at the same time. There are two ways to measure leakage, one is the resistance method, and the other is the voltage method. Regardless of the resistance method or the voltage method, the red test lead is inserted into the VΩ hole of the multimeter, and the black test lead is inserted into the COM hole of the multimeter.
How to measure whether an electrical device is leaking by the resistance method, first turn off the power of the electrical device, use a multimeter, and first adjust the position of the multimeter to the beeping position of the resistance. One test lead of the multimeter is placed on the shell of the electrical equipment, and the other test lead is placed on the live wire and the neutral line respectively. If the multimeter makes a sound, it means that the electrical equipment has a serious leakage, and the location of the leakage must be checked.
If the multimeter does not make a sound, it is necessary to increase the resistance level of the multimeter step by step until the resistance value is measured. Generally, if the resistance value is lower than 0.38M ohm, it is leakage, and if it is higher than 0.38M ohm, it is no leakage.
Measure the leakage of electrical equipment by voltage method, close the switch of the electrical equipment, and turn the gear of the multimeter to the gear of AC 700V (the gear of each multimeter may be different, adjust to the maximum gear of the current gear), the red of the multimeter The test lead is placed on the shell of the electrical equipment, the black test lead is placed on the zero line, the multimeter displays the voltage, indicating that the electrical equipment is leaking, and the multimeter shows that the voltage is zero, indicating that there is no leakage.
The voltage method has certain limitations in measuring leakage. It can only measure the leakage of the live wire, but not the leakage of the neutral wire. If there are capacitive components in electrical equipment, it will also affect the measurement accuracy of the voltage method, so the voltage method is not recommended.
How to use multimeter to detect short circuit
A short circuit means that two lines that should not be connected are connected. A short circuit is between phases and phases, and between phases and ground. One is a phase-to-phase short circuit and the other is a ground short circuit. Grounding is relative grounding, and grounding is divided into dead grounding. The larger the resistance between the phase and the ground, the better, and the small resistance is called leakage.
When measuring with a multimeter, the larger the phase-to-phase resistance, the better. The small resistance between phases is called phase-to-phase leakage, and the resistance to zero is called phase-to-phase short circuit.
Use a multimeter to measure both ends of a line. If the resistance is zero, the line is connected. If the resistance is infinite, it is an open circuit. Sometimes the resistance is zero and sometimes it is not, indicating that the line is virtual connected and disconnected.
Put a wire on the ground, with both ends guided without touching the ground, connect one end of the test lead to the wire, and the other test lead to the ground. The larger the resistance, the better, indicating a high connection value, and a small resistance value indicates leakage and poor insulation performance. Generally not less than 0.5 megohm, the state stipulates 1V1 ohm, low resistance wires should be scrapped.
