TL:DR Summary: Testing covers your backside and may save your life
It’s all a bit of a scam isn’t it? Money for old rope and a tiresome, expensive box-ticking exercise invented by someone to make work for people who haven’t got anything better to do with their lives. At least, that’s what I used to think, but I’ve changed my mind. Come with me on a journey to find out why.
It all begins with the fundamental issue: The electricity we use every day to help our day to day lives is potentially lethal. It’s easy to dismiss the potential severity, largely because the measures we use to protect ourselves, like safety plugs, RCD/RCBO, are mostly effective. The trend these days to what are called “Double Insulated” devices (where the user should never come into contact with the power supply) also makes the incidence of electric shock lower. But, in the way of these things, it can also make the effect of accidental exposure higher. Let’s come back to that, and look for a moment at what the legislation sets out to do.
It starts from the premise that if you own an electric appliance, you are responsible for its safety. That’s a very reasonable statement, but of course, aside from looking at the thing, how on earth are you expected to take a position on its safety, unless that is, you are an electrician. Actually, even an electrician won’t be able to tell any more by looking at it, the only way you can tell how safe it is, is by testing with specialist equipment. Enter stage left the whole industry of Portable Appliance Testing.
The tester works on your behalf to check the safety of the device, in two primary areas. One is, the insulation of the device – does it offer sufficient protection from the live conductor? Let’s be honest, the answer to that is mostly going to be yes, or you would have found out the hard way. The second less well understood part, is the earth connection, in the cable and on the device. Most safety devices depend on the earth return for their operation; if that is compromised you will know nothing about it in normal use, but when you need it to save a life, it may simply not work. The only way you will know aout it, is by PAT testing or when it is too late.
When I started looking at this, as might be expected, I tested all my own devices at home. I only ever buy top quality branded equipment, so I was looking forward to straight passes for everything. Until I started on my extension leads. Here’s one:
Not the youngest but good quality and worked OK, anything plugged in worked just fine. But, the earth resistance was high enough to mean that if, for example, I cut through a flex by accident, the breaker might not have tripped.
With this one, which again showed all signs of working properly, the earth connection just wasn’t there, which could have been potentially lethal
I binned them both.
So, of course, new stuff is always going to OK? If only.
I went out and bought me a few new extensions. The two smaller ones were fine. The third, the big 20m one from a big brand, sold in all the stores, “Guaranteed for 5 years” failed. Even new, the earth connection was outside permitted levels, who knows what it would be like after a couple of years of use. Of course, when testing you have to allow for the internal resistance of the cable, but even so it was about 50% over the maximum allowed. That fault would have been totally invisible in use; invisible that is until a good earth connection was needed and then…..
That got sent back straight away.
So, while the chances of you being harmed by equipment is thankfully very low, and most people get by fine without PAT, testing can help prevent a significant harm or injury. Where your equipment does that to someone else, insurers rather like you to have taken all reasonable steps to prevent it, some local authorities mandate testing (even though it isn’t strictly speaking a legal requirement) and it is also a small price for peace of mind.