How to: Megger Insulation

Meggar has been making electrical test equipment since the early 1900s. Their line of insulation testers can tell an electrician a wire's insulation resistance. This is important to understanding if the insulation is in good shape and protecting the conductors from interference. A wire's insulation is the protective coating applied to the exterior of each conductor. It is commonly plastic but can also be paper, polypropylene and silicone. Testing this insulation is done with a Meggar insulation tester.

Instructions

1. • 1

     Move the selector switch on the insulation tester to the voltage of the wires being tested.

   • 2

     Connect the "+" test lead to the hot wire. In residential electrical, this is typically the red or black wire.

   • 3

     Connect the "-" test lead to the neutral wire. In residential electrical, this is typically the white wire.

   • 4

     Press the "Test" button on the insulation tester. If your unit is a manual device, crank the hand crank at less than 180 revolutions per minute.

   • 5

     Look at the meter's needle for the indicate value of the insulation resistance in "MΩ".