Carrying out an Earth Continuity Test

This test is carried out on all Class I appliances. The purpose of the test is to check that there is a good connection between the Earth pin on the plug and the case of the appliance. A good connection is defined as having a resistance of less than 0.1 ohms (or 100 milliohms).

(This blog post is a chapter extract from the "Manual of Portable Appliance Testing")

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.