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?"

Fixed Electrical Appliance Testing

A few weeks ago a customer inquired whether we provide test leads to go with our PAT Testers to test Fixed Appliances. When we asked why he wanted to do this, he said he had been advised to do this on a course based around the 4th Edition of the IET COP. 

This post tries to put the record straight.

Earth Continuity testing - 20 Amps or 200 mAmps

Following a recent Twitter campaign, we had a training organisation challenging the use of 200 mA for testing Earth Continuity. As it is impossible to respond comprehensively using Twitter, here is my view on the use of 200 mA for testing not only IT equipment but all equipment.

IET Code of Practice - some useful advice

There has been much criticism of the latest edition of the Code of Practice recently including on this blog. However trawling through Edition 4, I came across some useful information that throws some light on an issue that has been puzzling me for some time. This is to do with cable rating and fuses.

IET Code of Practice - labelling

The 4th edition of the IET Code of Practice covering PAT testing makes a new recommendation on labelling as follows. "The date for re-testing should not be marked on the label". The duty holder is supposed to keep this in his or her records.

Edition 4 of the IET COP - Selling used electrical items

The new edition of the IET Code of Practice was launched last week. The preview information promised a new section presenting advice on the sale of pre-owned equipment so understandably I was quite excited. This promised to be good news for charity shops.

Edition 4 of IET Code of Practice launched

The long awaitied IET Code of Practice landed on my desk today and cost me £48.40. The previous editions came out in 1994,2001 and 2007; so only 5 years have elapsed since the last edition.