How do I use a multimeter to check if a line is shorted or grounded?
Multimeter as the electrician's most common and most practical instrument, although the use of simple, but if it is used well, can be said to be powerful. Here to tell you a little bit about the multimeter's introductory use and how to check the line is short-circuit or ground, I hope to give the beginner electrician some inspiration.
The use of multimeter
1. Use the multimeter to detect breaks in wires.
As the outer layer of the wire wrapped with insulation, the internal breakpoints are difficult to see, with the traditional multimeter detection is very troublesome, need to use the resistance, a section of the test, time-consuming, but also very easy to break the wire. And now the digital one is much simpler, connect one end of the wire with the phase line, the other end is suspended. One hand pinch the tip of the black pen, the other hand holding the red pen, so that the tip of the wire along the insulation layer slowly from the end of the phase line connected to start moving backward. When the multimeter's voltage reading suddenly becomes small (equivalent to one-tenth of the original reading), from here back to 15CM is the break point of the wire.
With this method only need to destroy a point of the wire to solve the problem, is not very convenient ah. This method can also be used to detect the break point of the electric blanket.
2. Use a multimeter to detect short-circuit faults in the circuit.
When the family's circuit has broken wires or circuit aging caused by a short circuit between the firewire and the zero line, generally the short circuit point is difficult to determine where, then the multimeter resistance method can be easily found. After the line short circuit, you should disconnect the main switch, unplug all electrical appliances. The multimeter is placed in the resistance file, the two pens are connected to the fire line and zero line, if the resistance value is zero or very small can be concluded that the short circuit. It is necessary to measure the resistance value between the fire wire and the zero line section by section, if necessary, you can cut off a section of wire to determine the short-circuit point.
This method can also be used to test the electrical motor good or bad.
