Mains test blocks are temporary power hubs where mains-powered equipment can be plugged into to test equipment. These blocks are also used to test the current and voltage levels of power circuits. Mains test blocks have plug-and-play attributes where the current can be tested without cutting the power supply. The test blocks operate on a make-before-break principle where the short-circuiting of the current transformers automatically occurs without requiring a switch for manual operation. What are mains test blocks used for?Mains test blocks are used for the testing of machinery to prevent damage to equipment if there are faulty currents or wires. These blocks are often used in laboratories, testbeds and service areas.Mains test blocks are used in transformers to test protection relays of secondary circuits. Test blocks are also applied to utility components to validate meter readings and calibrations. In factories, mains test blocks are also used to repair and replace equipment without having to disconnect or modify the power cable attached.Types of mains test blocksMains test blocks are categorised by voltage, rating, connection type and pole count.