Wee-Megger is one of a kind of self-contained-high-generator and is very useful for finding an equipment’s insulation as well as its large resistive value. As the current generated by a battery driven test equipment is very low, it is highly difficult and less accurate to find a large resistance with that. To correctly measure it, it is essential that a large current is used. The other necessity to use a large current is to find out any break down in cable’s insulation.

A view of Wee megger

One of the most vital tests for the condition of an electrical circuit is measurement of its insulation resistance. This test can reveal damaged or low cable insulation. These type of defects are almost undetectable if the cable/circuit lays underground or behind panels. An ordinary multimeter may be unsuitable for checking the condition of a 230-volt power circuit.

How to use a Wee-megger

  • Connect the positive end of the Wee-megger to the conductive material of the ‘Load’ to be measured and the negative end to the earth/ground point. Now start rotating the hand-wheel with a slow and steady speed.
  • The pointer will start to move and will steady at a point in the scale. Note the reading carefully. If the scale does not move or near to zero, then the insulation is very low. For a safe working environment, the insulation must be in Mohms.

You can also test a capacitor with the help of Wee-Megger. To do so, just connect it to both the ends of Wee-megger and start rotating the hand-wheel. If the capacitor is fine and started to charge, then the pointer will show steady increase in its resistive

Precautions:

  1. Do not touch the connecting leads with bare hand when handle is being rotated.
  2. Short capacitor terminal before and after testing to discharge any charge left on it.
  3. To achieve optimum results rotate Wee-megger at 120 RPM.

To know about other test equipments, visit the Test Equipment column in Navigation page.

Ratna is a B.E (Computer Science) and has work experience in UK Mainframe IT industry. She is also an active Web Designer. She is an author, editor and core partner at Electricalfundablog.