The protection obstruction (IR) test (additionally usually known as a Megger) is a spot protection test which utilizes a connected DC voltage (commonly either 250Vdc, 500Vdc or 1,000Vdc for low voltage hardware <600V and 2,500Vdc and 5,000Vdc for high voltage gear) to gauge protection opposition in either kΩ, MΩ or Gω.

Applications: Insulation Resistance Measurement of Electrical Equipment like Motors, Transformers, Machines, etc., Electrical Cables for Distribution Networks, for Communication Networks, House Hold Appliances (Washing Machines, Mixer, Toaster, etc.), Industrial, Commercial and Residential Installations.