TESCO has redesigned our Test Plug (Catalog No. 1077) for use with all test switch current test jacks, making testing quicker, safer and more accurate. Frequently used for in-service CT burden testing, and current injection when testing watt-hour meters. The Test Plug eliminates the possibility of opening current transformer secondaries. It is compact and polarized with convenient terminals for fastening leads. The Test Plug may also be used as an insulating plug. 20 Amp Rating (with appropriate leads). Contour Molded Housing (for ease of use with insulated gloves). Works with most test switches and jacks.