Why Portable Appliance Testing is important, you Idiots

Portable Appliance Testing (commonly known as PAT testing) is often spoken of with disdain in schools, cast aside as bureaucratic red-tape and disregarded along with countless other health & safety provisions. Teachers are particularly given to ignore it when they decide to bring in their own equipment from home, happily hooking it up to the mains without caring that it hasn’t been safety tested, because “they need it”, that all-powerful of reasons that many believe allows them to bypass any and all rules & laws (notably including copyright and data protection).

But I digress! Here’s just one good reason why PAT testing is actually important:

Last time these power supplies (all from old model RM Classboards) were checked, they passed. Now, time has rendered the plastic so brittle that all I had to do was grasp them and they literally fell apart in my hands. If they were plugged into a live socket, touching the now exposed innards would most likely give you a 230V electric shock.

“Ah, but AT,” I hear you protest, “I am not such a dumbass that I wouldn’t notice something in such poor condition. I would never allow such shoddiness is MY classroom!” Well, none of the class teachers in which these power supplies resided had noticed, despite them being in prominent positions in easy reach of pupils. The main reason is that most of them looked fine, until you either looked closely or handled them.

What’s more, experience has taught me that even an obvious fault cannot preclude a potentially fatal incident. Remember just now when I said that touching the insides would likely give you a 230V shock? I know that because two years ago, a teacher did just that with a similarly-damaged speaker PSU, despite admitting afterwards that she could clearly see that the live parts were exposed. Luckily she was not seriously injured, but the effects could have been more severe for a small child.

Hopefully this illustrates that PAT testing is not simply an exercise in box ticking. Failure to do it, and re-do it regularly, can put both staff and pupils at serious risk of harm. If it’s you that’s responsible for it, get it done. If it’s someone else, savagely beat them until they do it.

(By the way, if you’re looking for an alternative to the outrageously overpriced replacement RM Classboard power supplies, I’ve been using these, which at the time of writing, were less than 1/5 of the price. Which is nice, given that I need to replace more than half of mine this summer.)

About The Angry Technician

The Angry Technician is an experienced IT professional in the UK education sector. Normally found in various states of annoyance on his blog. All views are those of his imaginary pet dog, Howard.

36 responses to “Why Portable Appliance Testing is important, you Idiots”

  1. Mike says :

    Isn’t it meant to be PA Testing? Surely calling it PAT Testing is really calling it “Portable Appliance Testing Testing”???

  2. Amadeus Phoenix says :

    We have people in doing PAT, who stick labels on the back “boxes” that go with the slightly older Optiplexes (the ones that cover the wiring), which then get jumbled up when we move PCs around, they stick them over the joins (both there and on monitors, making them harder to get off the stands), and of course the labels leave power cables sticky and horrid. Of course it’s needed, but the way it’s done can often be a pain.

    We also had them test and re-wrap an entire crate of power supplies that we were just planning on throwing out.

    • AngryTechnician says :

      The stickers are the bane of my existence – especially the ones on power cables, for the exact reason you’ve mentioned. I really wish it wasn’t mandatory to have them, but I can see why it is.

      • Amadeus Phoenix says :

        There’s little worse than going to move a power cable and getting that gunk all over your hand.

        There is the time I had to scrape dried paint, or possibly even plaster, off the ends of an audio cable before I could plug it in. But that’s another story.

  3. Brett says :

    We had some that put stickers on the backs of our servers…….. yep nicely covering the vents….

    One of our servers actually overheated and shutdown.. (no remote monitoring at that time!)

  4. ScottishTech says :

    Ahh.. PAT people – how we love you.

    We’ll just unplug your severs – need to be PAT tested, y’know. Oh and that network cabinet. What’s that? Some advance warning or an appropriate time window to do this in?? Nah, we’ll just yank the power out during the day. 2 minutes, squire. See? Bish bash.. Oh. It’s not switching back on. D’you need that to be working?

    The PAT stickers our lot use are of the foil variety – supposedly much harder to remove..

    However, the cretins (sorry – pupils) here are a particularly diligent lot, not ones to avoid spending large amount of time meeting new challenges and I soon find labels attached to all manner of things.

    • TheCrust says :

      The way we prevent the PAT people arbitrarily unplugging our servers or network cabinets is to directly connect them into the mains via fused spurs and the appropriate wall plates. The servers that is, not the PAT people (though that thought has often occurred. Grrr. Sticky labels….!)

      Our on-site electrician is happy with this solution and the annual PAT people leave kit well alone when they’re roaming around because it is then covered under the fixed electrical testing cycle and not part of their remit (be honest, how “portable” are most servers or switches once sited anyway?)

    • Amadeus Phoenix says :

      When you said cretins, I assumed this was going to be about the teachers

  5. leskeys says :

    i hear what your saying and safety is paramount, however, PAT is only as good as the day of the test. its a massive waste of time and money. you test an item annualy on Monday it develops a break or loose wire on Tuesday…..system pointless!! It is unlikely to protect anyone in the long run. There are no plausible stats showing multiple deaths of children from non PAT equipment when off-site from school. Also many commercial venues demand to see your PAT, however they refuse to show you theirs!

    • AngryTechnician says :

      What system of safety testing would you propose instead?

      • Scotty says :

        “There are no plausible stats showing multiple deaths of children from non PAT equipment when off-site from school.”

        To quote government figures: In 2007 over 60 percent of all accidental house fires were caused by electrical equipment.

    • Portable Appliance Testing says :

      Therefore you’re saying you should never test anything because it might go wrong the next day. So, shouldn’t we do an MOT because the car might go wrong the day after?

      In most cases a fault won’t cause serious damage as soon as it occurs. Regular PAT testing hopefully it means the problem is spotted before an incident.

    • gordon will says :

      i would like to know how many people have been killed on construction sites because of faulty 110v tools its a complete scam

  6. Jody Bridger says :

    Hmmmm. Im the director of a PAT Testing company in Sheffield and yes your right, its only safe at point of test………..but so is your car M.O.T but you wouldnt drive around in that untested would you??

    Its part of the electricity at works act that employees should visually inspect electrical appliances for signs of damage on a regular basis, hwhat percentage actually do? i imagine its very low dont you?

    Incidently PAT Testing is just as much about fire risk as it is risk of electrocution

    • sahmeepee says :

      You’ll probably be aware of this page from the HSE then:


      PAT testing is not required and tests a very specific set of conditions. The problem highlighted in the post does not require a fancy PAT testing machine or a highly-qualified expert. A standard visual inspection could be done by any IT technician without charging ~ 50p per device (where a PC and monitor can equate to anything up to 4 “devices”). What’s more, it could be done more often than once per year and without the interruption of turning each device off.

      Safety: yes please. Snake oil: no thanks.

  7. Giles says :

    I can add MANY similar photos including one where the whole front of a power socket was hanging off the wall – bare, live copper exposed.

    Suggested maybe not teaching in the room until repaired…


  8. Rob says :

    PAT testing is a waste of time and just a money spinner for those who do the few hours training required for anyone who can stand up straight long enough to carry it out! In a domestic property if you fit a consumer unit that’s RCD protected there is no chance that a portable appliance could cause injury! As someone has already pointed out if you test on a monday and the item aquires a fault on the Tuesday what good will the PAT test have done? It’s the nanny state gone mad and I have no doubt there will be a requirement to fit a bath water temprature monitors in rental properties quite soon. Get the PAT test stickers off ebay for 10 quid and stick them on yourself for all it’s worth.

    • The Angry Technician says :

      As I said in the post, a faulty power adapter a lot like the one above did in fact shock one of our staff a few years ago, and it wasn’t pleasant for them. The risk does exist. As for the argument that equipment could go faulty the day after the test, by that logic we should all be faking the MoT certificates for our cars as they are also worthless. Do you do that?

      • rob says :

        I noticed you sidestepped the RCD issue, I have 10 buy to lets and use 2 very good sparkys. They are both part p’s one with 24 years of experience. I spoke to one today regarding a PAT on some items in a house I have just re-let. He told me this. “Even you tried to create a dangerous situation with an appliance the RCD protectors are so quick that it would be almost IMPOSSIBLE to electrocute yourself. This guy did all the re-wiring and certification for me in a 9 bed house to flats conversion last year. The MOT on a car is not needed for 3 years if its a new car. I can buy a new washing machine and rent a property to someone for 6 months, then they leave and I re-let. Aparently the washer will need re-testing for some reason? I can sell the car after 12 months with no checks? Some cars can do 150 MPH? Go figure that one. It’s a waste of time and a rip off. I buy the stickers and put them on myself and I will never have a problem. The real joke is that there is no required certificate of competence for PAT testers either? My Sister has a care home and one of her staff who is in her words “Brainless” does all the PAT testing after she had 3 hours training??? Its a money spinning joke get the stickers off e-bay 2000 for 10 quid. Job done.

        • The Angry Technician says :

          The building the teacher was shocked in has RCDs. They still got hurt. The whole point of my post is really that regular checks are a good idea, and that if PAT didn’t exist, its likely that a lot of businesses would not make checks at all.

          I have first hand experience of someone I know getting hurt from faulty equipment. Perhaps when someone you know gets hurt from faulty equipment that would have been caught by a regular check, you might change your mind.

          • rob says :

            I would prefer to take the advice of someone who has 24yrs of experience and a recognised qualification than someone who has 3 hours traning and a PAT testing machine. It’s a bit like asking a PCSO or going to the Police station for advice. PAT testing IS a waste of time, you know it and so do I. The only difference is you make money from it and therefore have a vested interest in carrying on the illusion. Your claim about the RCD protection not kicking in before someone get’s injured is very very suspect and In my opinion 100% untrue. It goes against everything I have been told by experienced professionals, neverthelss it conveniently fits your argument. My roll of stickers will be fine and I advise anyone to get some. If you are really bothered borrow a PAT testing machine and look at a video of how to use it. That’s sufficiant enough. NO qulification is required that’s how much of a joke PAT testing is. Making the claim that it’s vital and saves lives is nothing but vacuous.

            • The Angry Technician says :

              I don’t do PAT testing, so your assumption about a vested interest is wrong. We have someone in house who does it for us, so no-one has made any money out of PAT testing on our site for quite a few years.

              The experience we had with those RCDs is something we saw for ourselves. It may not be what’s supposed to happened, but it did. However, given that you’ve already accused me of lying, I don’t really expect you to believe me anyway.

            • rob says :

              I found this on the net not long after I had the chat with my sparky about PAT’s.

              In the past 17 years, 29 people including eight children have been electrocuted in homes in Western Australia. These deaths could have been prevented if Residual Current Devices (RCDs) had been fitted to the power and lighting circuits.

              Electrical hazards are often hidden and can be difficult to identify, such as a small hole in an extension lead or a power board damaged internally. Electrical accidents occur in an instant. RCDs are the only device that can protect your family from these hidden dangers and give them a second chance.

              RCDs detect an imbalance in the electrical current and disconnect the power within 10 to 50 milliseconds, preventing electrocution and fire.

              Installing at least two RCDs in your meter box or distribution board and testing them regularly is a small investment in money and time. It will provide long term protection for you and your family against serious injury and death.

              As I said even if you do a PAT test on a Monday and the fault occurs on a Tuesday the RCD is the critical element required to avoid injury. The PAT test would have been meaningless. It’s a one time test once every year.

              There may well be a strong argument for having a qualified electrician check the Consumer unit every 6 to 12 months but nothing more. PAT testing was created to make money. As were the HIP’s that were eventually scrapped, as PAT testing should be.

  9. rob says :

    Here is something interesting I was at the Soilcitors this morning and asked him about my liability regarding PAT testing. We had a look on the net for the current legislation on PAT’s. There is NO requirement for a vaild certificate only a requirement to be competent in using a PAT device. Therfore you can test an appliance by checking the plug and using it then put a sticker on it. Even if there was a problem in the future you would not be liable as long as you can show you know enough about using a PAT testing and said you had borrowed a tester to use. Thats how much of a farce this legislation is.

    • The Angry Technician says :

      OK, right, I get it, you hate PAT testing and are only concerned with doing the bare minimum to avoid legal liability. We’re going to keep doing regular checks because annoying your customers by electrocuting their children is bad for business even if they can’t sue you. You do whatever you want.

      • paul says :

        Another point to bear in mind, is how many people are actually killed by the actual electric shock. I don’t know the figures but I am well aware of the fact that a good number of people are killed as a result of the shock rather than the shock itself.
        The most common example of this is falling and hitting their head, or braking their neck as they land after recieving a shock which would not have normally been sufficient to kill them.
        As your electrician states it is virtually impossible to be electrocuted if you have an RCD on the installation (assuming it is in correct working order and is of the correct rating etc), but go back and ask him if it is impossible to recieve an electric shock with such a device. You might be surprised by the answer to this one, although I don’t really expect you to change your opinion.

  10. paul says :

    Rob, the RCD is all well and good for protesting against electric shocks, but ask your electrician(s) about the protection against overcurrent? I have seen an oven catch fire (yes pretty ironic) due to a poor connection on the control circuit. The RCD did not protect the circuit until a considerable amount of smoke and toxic fumes had been produced, this could have produced a very nasty result. It was because the control circuit was of a much lower current than the main oven itself that the fault was allowed to buiold up to a dangerous temperature.
    A decent PAT test may well have shown that the fault was there and then possibly been rectified, try to remember that the PAT test is not just about electric shock prevention, but fire as well.
    By putting a label on yourself without a test could land you in some serious trouble if a fault of any kind occurs, as you would not be able to show any justification for the sticker being placed on the appliance. A tester should be able to produce a diocumenty showing all of the test result which would prove that they had done a full test and that the appliance was deemed to be safe at that time.
    If you were to have to appear in court to explain your actions, you would have a difficult time indeed explaining yourself. In fact you would be better off no placing labels on an untested appliance.
    You are quite right that it is too easy for someone to set themselves up as a PAT tester, and that there is no proper certification for it. And this unfortunately gives a bad name to those who are qualified, using proper equipment and doing a thorough job.
    As a fully qualified electrican with 20 years experience, I do some PAT testing, but often try to put the customer off if I don’t think that they need it. Why? because first up I hate PAT tetsing climbing under desks, pulling out washing machines etc. And also because the majority of potential customers don’t really need it doing, they have been told by certain people (usually man in the pub) that they need it.
    The worst case I saw was a beauty salon being tested every 6 months, that was everything they had there! The previous electrican was makin a a tidy sum out of them because they didn’t know what they really needed or what the law really required (a whole massive grey area that bit).
    PAT testing is necessary in many places, it proves that appliances are in good safe working order, and gives peace of mind to all concerned

    • Tony says :

      Having done the exam with First S their books state a hand held device such as I guess was used in the beauty saloon you mention should be tested at 6 month intervals. So why are you mocking that tester? I am only asking for clarification please

  11. phill says :

    of course rcd’s can go faulty and indeed they are also now subject to a test. as said they dont protect against overcurrent – and they dont protect from live to neutral short circuits – where you could be insulated from earth but happen to touch a broken and exposed live and neutral conductor – you complete the short circuit.
    a pat testing visual inspection would detect this.
    an rcd also cannot detect foil or an incorrect size fuse placed in a plug instead of the correct sized fuse.
    and for many establishments of a smaller nature it can be more cost effective to get simply get tested than to upgrade the consumer unit to one that that supports rcd, mcb, rcbo, rccb or whatever
    an rcd can also not spot or detect daisy chaining extension leads or bad practice

  12. phill says :

    as a matter of course i test the rcd, i also look at the consumer unit and do a quick appraisal of the protective disconnection devices fitted. and do a ELI test just for completeness and advise if the ELI fails that it will need further investigtion

    • James says :

      So you go to pat test an item, and while your doing this you check the over current device for the circuit its plugged into, it’s rating and type, then check bs7671 to see the max zs and then do an earth loop test and compare the result to the max zs table?


  13. James says :

    I put PAT in with other stupid requirements of the nanny state that supports a culture of “sue their arses” whenever it is possible to lay blame. The programme must nationally cost at least £50 million a year (50p a plug and there has got to be at least 100 million workplace plugs). Ask yourself if this money could be better spent elsewhere – the NHS, Schools, Pensions are all desparate for money and more deserved. No home owner gets it done, because it is poor value for money, whereas most homes now have an RCD because it is good value for money.

    Why not consider making the UK the best possible place to live and work given the limited resources available to us, instead of being scared to make cost effective decisions whenever someone argues “but someone might get hurt”.

    You really want to stop people getting hurt? 1900 people a year die on our roads. Reduce AND ENFORCE a national speed limit of 60mph and you will save lives AND save fuel and hence reduce the national deficit. Obvious really.

    You really want to stop people getting hurt? A guardian article recently stated that claims for clinical negligence outstanding at 31 March 2010 could cost the NHS £15.7 billion. Make the NHS legally obliged to only have to say “sorry” and promise to better next time and that £15.7 billion could actually be spent providing better health care. Obvious really.

    But then why do the obvious when we can have box ticking programmes such as PAT.

  14. Brian J Hoskins (@BH_79) says :

    PAT is definitely a necessity in industry, and any argument that attempts to make a case for completely ruling out PAT in industry will not stand up to rational scrutiny. This is because industry is subject to constant change and as a result equipment will be moved around, cables will be plugged in and out, and installations will be modified, expanded, or sometimes dismantled with some parts of it being re-used on new installations. The higher the frequency of change, the greater the risk. In my line of work, for example, it is not uncommon for electrical equipment setups to be created on one day and then rearranged somewhere else on the next. All of this change creates the potential for scenarios where equipment will inadvertently become unsafe, and this is where PAT has a genuine roll to play in the workplace.

    The only trouble is, the remit of PAT has been grossly exaggerated, to the point that most businesses now subject every single piece of ‘portable’ equipment on the premises to PAT on an annual basis. This defies common sense (or, at least, sense that is common among industry professionals) and has made a complete mockery of the PAT requirements. This is the main reason why people will oppose PAT in the workplace – they don’t want to pay thousands and thousands of pounds to subject every PC monitor and workstation and telephone etc to ‘silly’ tests every single year, especially when these items haven’t been moved since the year before.
    This isn’t actually a requirement of PAT, but many businesses have been lead to believe that it is and hence the backlash.


    Some peolple are arguing that it’s impossible to have an electric shock if RCD protection is used. This is not true.
    Live electronics will not cease to provide energy to an earthed load just because you trip an RCD. All the RCD does is prevent *further* energy being supplied to the live electronics. But any energy that is already stored in the electrical equipment will be delivered to the load (the load being you, if you’ve placed your hands on it) with potentially enough kick to give you a very nasty electrical shock. Anyone who has ever accidentally touched a fully charged reservoir capacitor will attest to this. You won’t want to touch any live conductor that is connected to one of those babies – and no RCD will prevent you having a shock if you do!

    • David Haxby says :

      I am a highly experienced electrical engineer/electrician/tutor and now I am in the bus pass category I do a little PA testing. What I find is that the tester will boringly churn out pass after pass on, say office appliances so these do seem a waste of time. In a factory or site environment where there are class 1 appliances the situation is different and I am always extra careful with these since this is where the real safety risk lies. Even so nearly all my failed tests are due to leads being pulled out of plugs and cuts to leads etc. Sometimes the machine will produce a pass but my experience tells me to fail it due to an unreliable earthing set up. My opinion is that that PA testing is good in that maintains a reasonable standard of practice but that too much emphasis is placed on the testing machine results. A visual check is probably more important and could be carried much quicker and more sensibly and this is what I do. Could I suggest that experience could be the crucial factor here?

  15. draelectricals says :

    This is a quality article; I wish I could be so open and honest at times! PAT testing is important; it helps to maintain safety on electrical appliances. Companies and organisations are supposed to maintain their electrical appliances in a safe manner but few do which leads to problems and accidents. PAT testing is important because of this, as it finds the problems and thus prevents the accidents.

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