What's the matter when the fuse at home blows? How to use a multimeter to measure the current?
Under normal circumstances, the following situations can cause the fuse to blow:
① Wire parallel connection in the circuit.
② Short circuit in the circuit.
③ Overloading, that is, using electrical appliances with a current exceeding the rated current at which the fuse will blow.
④ Incorrect installation of the knife switch. When connecting the knife switch, if the wire ends are not tightened and the fuse is not firmly crimped, it is likely to cause the joint to generate high temperature and heat during use, thus making the fuse likely to blow as well.
The second question is: How to use a multimeter to measure the current?
When using a multimeter to measure the current, adjust the range switch of the multimeter to the AC voltage and current range. You can first estimate the total load of all the electrical appliances at home. Then, adjust the multimeter to a range greater than or equal to the total current of the household electricity and connect it in series in the circuit for measurement. (Pay attention to operation safety to prevent electric shock. It is not recommended for non-professionals to operate.)
Since the current range of the multimeter is relatively small, it is recommended to use a special instrument with a larger range, such as a clamp ammeter. Just place the single-phase wire to be measured in the clamp of the clamp ammeter (Note: switch the range switch of the clamp ammeter to the appropriate current range of the clamp ammeter). The number displayed at this time is the current (in amperes) of the electricity consumption at this moment.
The reasons for the fuse blowing are nothing more than overloading and short circuit. Fuses (fuse tubes) have a rated load, and they will blow when the load is exceeded. When the electrical equipment does not exceed the applicable range of the fuse, there is basically a problem with an individual circuit. And some ordinary multimeters can only measure DC current and cannot be connected in series to an AC circuit. Generally, for maintenance, it is necessary to open the circuit locally and then check the power supply. If the fuse no longer blows after a certain part is disconnected, the fault range can basically be determined. If the fuse still blows after all the loads are disconnected, it can be determined that there is a problem with the circuit. Disconnect the power supply and the load, and use the resistance range of the multimeter to measure the resistance between the wires. If it is conductive, it means there is a problem with the circuit, and the only solution is to replace the wires or rewire. It is advisable to invite a professional electrician for maintenance and do not operate casually. After all, electricity is a "dangerous tiger", and do not carry out dangerous operations.
