Key changes in Edition 5 of the Code of Practice for In-service Inspection and Testing of Electrical Equipment

 Edition 5 of the Code of Practice has been updated significantly. Below is a summary of the major ones that have been taken into account during the update to this handbook.

Risk Based Frequency of Portable Appliance Testing

Edition 5 of the IET Code Of Practice (The official guide to PAT Testing) encourages the duty holder to carry out a risk assessment and gives various examples. In Chapter 7 of this handbook, we provide both a way of carrying out a risk assessment and a Table based guidance on how the frequency of maintenance can be worked out.

500 V Insulation Resistance test and the IET Code of Practice (4th Edition)

The IET code of Practice says (section 15.5) that the 500 V Insulation Resistance test is a "hard test" and that it can "damage IT equipment or other equipment containing electronic components". We look at what this means and whether it makes sense.

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")

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.

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.

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.