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Wednesday, 15 April 2015

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")

Thursday, 13 November 2014

Do consumers really understand test instruments?

As an experiment, I recently posted a question on Amazon against a 'Microwave Leakage Detector' that sold for £10 compared to others that were selling for around £50. Not surprisingly the £10 seemed to be selling well and I was interested to see if customers were driven by price only. Below are the answers from customers and my views on this.

Friday, 17 October 2014

Avoiding serious injury from an electric shock



We get an electric shock when current passes through our body due to a voltage difference. For example, if we touch a live wire at 230V, this voltage pressure will try and push current through our body to the ground that we are standing on. This is because the mains supply in a building is always at 230V with respect to the earth.

Thursday, 4 September 2014

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.

Wednesday, 20 August 2014

PAT Testing Electric kettles and other kitchen appliances

A variety of electrical appliances are in use in a normal kitchen. This chapter deals with PAT Testing of these - This is an extract from the PAT Testing Handbook published by First Stop Safety and available on Amazon

Monday, 17 February 2014

Round 3 pin plugs with no fuses

The issue of round pin unfused plugs often comes up during PAT Testing courses or as a telephone technical support question. This post gives more detail on this subject.

Monday, 3 February 2014

Why a 13 Amp fuse does not seem to blow at 20 Amp

Last week, an apprentice at work showed me a plug on an extension lead that had overheated and was in a dangerous condition. He said that he had two 2 kW heaters plugged in. His question to me was "The current was around 17 Amps - why did the 13 Amp fuse not blow and protect the plug from overheating?"