The Martindale CP501 Check Plug is a popular socket tester that quickly ensures the correct wiring of plug sockets and gives indication of this via three bright LEDs. The pattern of lit LEDs will demonstrate the type of fault detected allowing unsafe sockets to be quickly identified and diagnosed.
This extremely handy portable appliance testing accessory is ideal for verifying the presence of an earth and can speed up the process of PAT testing multiple extension lead sockets.