Electrical Test : Insulation resistance test

Insulation resistance test are so important test in electrical wiring.If your house wiring cable are safe and no wounded,the cable will won't interference to other cable.If the cable is wounded,there's high chance short circuit or earth fault happen To make sure your house wiring are safe,insulation resistance test will determine it by doing this test.

The picture above shown is the meter used to test insulation resistance for your house wiring. This meter called Meggar Meter. This meter works similar to Multimeter. You can se this meter to test polarity and continuity test and the range are provided with 250-1000 AC V and 20Ω-2000Ω. Modern megger meter have test button,but old classic meggar meter have pedal to spin to produce AC current for send current flow through the wire to test. In good condition, the meggar ohm will show infinite in the meter. It's means your house wire are in good condition.

We now know the tools,but we don't know how to use this meter for test. Let's look about it.In insulation resistance test, there's two probe. One is Live and another is Earth or Ground.  So one probe point at the first terminal and earth probe are point at other terminal. So the probe pointing the terminal are like this for

Single Phase :
N-L
E-L  
N-E

Three Phase :

R-Y
Y-B
B-R
E-B
E-Y
E-R
N-R
N-Y
N-B
N-E   

Let's look some example how to use this meggar meter.

This picture above shown is insulation resistance test are check in three phase distribution board that Live probe are point at Red phase and earth probe point at Neutral.

This picture above shown is insulation test are check on light bulb. Ih this test, live probe are point at Live terminal and ground probe are point at earth.

This picture shown is insulation test are check in 13A socket. In this test live probe are point at earth and ground probe are point at neutral.