Connections For Testing Insulation Resistance Of Electrical Equipment

Testing Insulation Resistance //

The following schemes show how to connect a Megger insulation tester to various types of electrical equipment. The schemes also show in principle how equipment must be disconnected from other circuits before the instrument is connected.

These illustrations are typical and will serve as guides for testing insulation resistance of practically all types of apparatus and conductors. Before proceeding with tests, read the part on Preparation of apparatus for test at the bottom of this article.

REMEMBER! The Megger insulation resistance tester measures whatever resistance is connected between its terminals. This may include series or parallel leakage paths through insulation or over its surface.

Electrical equipment to test //

1. AC Motors and Starting Equipment
2. DC Generators and Motors
3. Wiring Installation
4. Appliances, Meters, Instruments and Other Electrical Apparatus
5. Control, Signaling and Communication Cables
6. Power Cables
7. Power Transformers
8. AC Generators

Important //

• Preparation of apparatus to test
• Safety precautions
• Video tutorials (46 min.)

1. AC Motors and Starting Equipment

Connections for testing the insulation resistance of a motor, starting equipment and connecting lines, in parallel. Note that the starter switch is in the “on” position for the test. It is always preferable to disconnect the component parts and test them separately in order to determine where weaknesses exist.

 

 

 

Figure 1 – Testing the insulation resistance of a motor

 

 

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