How to measure the insulation of wires with a multimeter
A multimeter is only capable of ordinary measurements of voltage, current and resistance or other. The multimeter is not capable of measuring the insulation of wires at all.
Wires and cables are tested by local quality and technical supervision bureaus or testing centres with special testing instruments, or commissioned by the manufacturers themselves.
According to GB/T5023.3-2008 standards for example; generally used polyvinyl chloride (PVC) copper-core wire or power cable BV450/750 1 × 1.5 wire, it requires a length of 5 metres, in a specially tailored sink, so that the water temperature is gradually warmed up to for (temperature 70 ± 2 ° C) immersed for no less than 2 hours, the insulation resistance value should be measured with a Professional testing instruments on the application of the corresponding DC voltage to carry out. Such a process should be divided into a total of 5 times to carry out.
The DC voltage of the internal power supply battery of a multimeter is generally 9V, which is not sufficient to determine and test the insulation of wires.
Cable insulation is best measured with a shaking table, the results of the multimeter measurement is not allowed, only valuation. But the cable insulation is seriously damaged, with a million meter to measure or more convenient to find out the problem. Resistance between the lines must be greater than 1M ohms, such as less than 1M, when used with care, but must exclude the cable into the water or moisture, if any, must be sun-dried and then measured.
Multimeter how to measure the circuit on and off? Multimeter to measure the circuit on and off
One of the simplest functions of the multimeter, you can switch the multimeter gear to the ohm representative symbol is (Ω). Remember the value of the two measuring pens together, and then use one of the measuring pens to connect to one end of the line to be measured and the other to connect to the other end on it, through is the value that you remembered not to have no response or a large value.
First of all, to ensure that the measured circuit is not electric, and then the multimeter to play in the ohm file, first of all, the multimeter of the two pens shorted to see whether the zero. If it does not come back, you should write down the value at this time, and then, and then use the multimeter to measure the circuit, if, the circuit under test and just experimented with the same resistance, then the point of the road is on.
The simplest with a multimeter to "Ω" ohm file test power plug L and N wire resistance, normal general resistance, such as good removal can be used to measure their own initial power cord with a multimeter plug to the inside of the pass or not, can be initially excluded from the power cord, the other inside the fuse, such as the use of the multimeter ohm file to measure whether the open-circuit (such as the electricity is unfamiliar with, not operate under electricity). (If you are not familiar with electricity, do not operate with electricity).
