One of our repairers asked me to test an extension lead he had acquired at a car boot sale. Our portable appliance tester can test extension leads: in the photo you can see the lead (orange) is plugged into the tester and then connected back at the other end (via the short black lead). The point of this is to check whether the earth wire is connected at both ends; and in this case, we see that the earth continuity test has failed.

How could this be?

The simple answer is that there was no earth lead in the cable, as this photo inside the socket shows. The manufacturers have used two-core flex, and also there’s no clamp on the cable, meaning it could easily be pulled out in use.

Not good. Lesson: get the car registration number when you buy anything potentially risky.