Enough is never enough. Although [David Johnson-Davies] has a couple of multimeters lying around, he still felt the urge to build a stand-alone continuity tester and has posted details for a super ...

Making a device to test an RCD is easy; a resistor between hot and the protective ground circuit would do. [Callan] over-engineers. He used a 50 W resistor where 30 W would do under the worst ...