When is a PAT tester not a PAT tester?

On our various Portable Appliance Testing courses I sometimes get asked whether one could use a £20 multimeter for PAT testing. I usually go through the reasons why this is not safe. Browsing on the web, I have come across what looks like a multimeter with a mains socket on the front that describes itself as a 'simplified version of a standard PAT tester'.

This is a very dangerous trend as it will lead customers to believe that they are actually carrying out a safety check that is meaningful. This blog sets out the reasons why using this instrument could PASS appliances that are dangerous.

Why does the Insulation Resistance test PASS with nothing plugged into the PAT tester?

This is a question we often get asked during the PAT testing courses. On any PAT tester, just press the Class II button. The tester will carry out the Insulation Resistance test and display a PASS - even with nothing plugged into the tester.

Why does this happen? Is the tester faulty? The answer is NO.