Depending on the method of inspection, as well as application and installation, a great deal of time and effort could be invested in verifying the electrical health and integrity of electrical insulation. However, insulation resistance tests can be a relatively quick and effortless method of inspecting insulation. This type of test can be applied to practically any electrical insulation. Test results are recorded, trended, and if appropriate, compared to manufacturer’s recommendations or industry standards and guidelines. A good insulator should have a very high resistance to leakage current. Environmental, electrical and mechanical stresses can aid in exploiting voids and the development of microscopic cracks. These phenomenon permit increased access for contaminants to migrate into the insulator or insulating systems. When this happens, there is an increased potential for electrical faults and system failures, which relates to compromised reliability of the electrical system.