Electrical Safety Testers
Electrical equipment receives many of electrical safety tests from manufacturers and standards organizations before consumer usage. Electrical safety testers are used in three different types of electrical safety tests: ground-wire continuity tests, operational and insulation tests.
Electrical Safety Testers – Ground Wire Continuity Test
These kind of electrical safety testers test the quality of three-wire power cords in metal-cased electrical products. No electrical current should pass through this wire during regular operation and, in the case of an electrical fault, the electrical product’s frame should hold at ground potential. If there was no ground wire, an electrical safety hazard could occur. Canadian and U.S. (CSA and UL) standards dictate that the ground-wire continuity must be verified using any indicating electrical safety testers. All electrical safety testers in North America must meet Canadian Standards Association (CSA) and Underwriters Laboratories (UL) standards in Canada and the U.S. respectively.
Electrical Safety Testers – Insulation Tests
These kind of electrical safety testers verify the insulation quality of an electrical product. The three kinds of insulation tests performed are:
Dielectric Strength (Hi-Pot): Electrical safety testers perform a production test by inspecting the spacing and insulating materials to see if they’re adequate. High-voltage electrical current is applied to the wires holding the electrical device’s case that carry the current at ground potential. If high-fault currents or a disruptive discharge occurs then the product is considered to be faulty. Results are either a PASS or FAIL.
Line-Voltage Leakage Current: Electrical safety testers conduct this test by operating the electrical product at a regular voltage, but keeping the ground-wire open. At that point, a milliampmeter is used to measure the shock that a person would receive during operation. The electrical safety device is connected to exposed metal parts in an area where the product and ground can be measured.
Insulation Resistance (IR): Electrical safety testers measure, record and study the insulating material of large motors and the wiring conditions in buildings for long-term stability, among other uses. Similarities exist between this test and the line-voltage leakage current text, except that the insulation resistance test isn’t ideal for testing the safety of electrical products.
Electrical Safety Testers -- Operational Tests
Electrical safety testers that perform operational tests check that the product can perform without drawing excessive current, overheating, or creating a hazard. A measurement of the product’s wattage or current draw will often accomplish this goal. Measurements in temperature and speed can also be performed.