Refresh Extension Lead Testing

To test an extension lead is pretty straight forward, however many people still find it confusing.

These days, it’s common for some PAT testing machines to have an IEC lead test facility which makes it easier to carry out tests on leads as all that is required is to plug in both ends of the lead and test earth continuity, insulation resistance and polarity.

However, depending on your PAT machine, you may need an adaptor or a short IEC lead which is made up of an IEC plug on one end and a 13A plug on the other.

To carry out the extension lead test simply follow the instructions below.

Once you have finished your visual inspection and are satisfied that the lead has passed this particular stage, it’s time to plug the 13A plug into the 13A socket on the tester, then plug the IEC plug from the IEC adaptor into the IEC socket of the tester, then connect the 13A plug on the short IEC lead into the end 13A socket.

It’s important at this stage that you plug this into the socket furthest away from mains lead end. This is done to ensure that the full length of the Buss Bars are tested. These are important as they connect all the pins in the socket together.

Then it is a case of carrying out the lead test with an earth continuity test, an insulation test and a polarity test.

The polarity test is carried out to identify whether the Line and Neutral are reversed. It’s a common misconception that it doesn’t matter whether the Line and Neutral are reversed, but this is in fact wrong and is very important that they are the correct way around. If they are reversed, i.e. the wrong way around, the switch and fuse are in the neutral leg, which means that the appliance is live even when switched off and if a fault develops on the appliance the fuse will not blow in this situation which is likely to lead to a fire.

Although not required, it’s always good to use a socket tester to prove the remaining sockets on the extension lead. To do this you need to unplug the extension lead after the PAT test has been completed and plug it into a mains socket, then plug the socket tester into the remaining sockets one at a time on the extension lead to ensure that all sockets on the lead are working correctly.

Written by Sara Thomson