There is a huge price range for PAT testers and presumably the more expensives one do more tests (?) do them more thoroughly (?) and/or faster? I just wonder though do *all* these testers enable a valid test certificate to be issued (by a qualified person). Why pay £900 for one when a £200 will do what's needed? I know these must be naive questions but would appreciate some enlightenment Thanks.
Mainly faster, so it becomes important if you're testing lots of things. For example, with the earth continuity test, you can do a test at 200mA which requires you to work your way along the full length of the cable wiggling it in all directions which probably takes a minute or two (or more likely doesn't happen), or you can use a tester which tests at 20A (IIRC) and does it in a second. There are those which will read the appliance asset tag barcode and record the test results internally for you to download all at once at the end of the day, and there are those with no recording facilities so you'll need to take a laptop or note pad with you and record it all manually, unless it's a one-off test (e.g. for selling a second-hand electrical appliance).
Then there are different tests too. If you are testing IT equipment, you'll need a tester which can measure earth leakage with the appliance in operation, whereas you can get away with just an insulation test if you aren't measuring IT equipment.
If you test lots of IEC cords, extension leads, combo leads, etc, you'll want a tester with the appropriate sockets and tests for these.
Very few people who do PAT testing are qualified to do so. In particular, qualified electricians are rarely qualified for PAT testing. You can easily tell those who aren't qualified, because they start the test by connecting the appliance up to the PAT tester. You can easily become qualified yourself, providing you know how to wire a plug and know the difference between milliohms and megohms.
In the case of a company which did our office out of hours, they sat at one of the tables and made up a brew when they arrived, and one of them wandered around the office slapping stickers on everything before rejoining their colleagues for another brew. They didn't seem to notice the copious and blatently obvious security cameras all around the office though. (We only went to look at the security tapes when we were rather surprised that none of the computers around the office had been powered off or rebooted during their PAT test.)
Some machines have other features, such as being able to test 110V appliances from a 240V supply or being able to test without a mains supply being available. Some basic machines can't test IT equipment.
Owain
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What happened? You refused to pay?
I thought about offering PAT testing, the course is reasonably priced, £500 - 750, but was put off by a perceived lack of customers. What is the going rate for the testing? Ta Alan.
Thanks all. I've been looking around for a bit more info on what these things do and by way of comic relief can recommend this little gem :-) (... but for those that are in a hurry I preview a sentence - well amost :-)
"Even then, measuring the earthling's resistance gets important when using the equipments."
AFAIK unless they have changed the rules lately you don't need to be "Qualified" but only need to be a "Competent Person".
I passed my "Competency" tests with 2 different PAT manufacturers some time ago. Clare and Seaward. Both issued competency "Certificates" which allowed me to use their equipment for testing. I worked within the hire trade at the time and tested anything from power drills to computer equipment. I'm a qualified engineer, not an electrician. Going rate for customers equipment was 50p per unit and £1 for the paperwork.
You don't legally need to be "Qualified", and there is no such thing as a "Competent Person" scheme for PAT testing.
HSE recognises C&G 2377/02 as the qualification which demonstrates competency to perform PAT testing, and that's what anyone performing PAT testing should have. Anyone responsible for managing a PAT testing regime should have C&G 2377/01. The two are normally done together, as there's a fair amount of overlap. They are intended to be easily achievable by lay persons. As I said before, 2377/02 only requires prerequisit basic electrical knowledge such as how to wire a plug and to know the difference between milliohms and megohms. The original thought was that you'd probably find at least one suitable person in any office/factory environment, and send them for the two day course. (Actually, it was the electricians taking 2377/02 who were really struggling with the milliohms and megohms.)
We did report it back, but I don't think anyone gave a shit -- it was probably more of a box-ticking arse-covering excersise than anything else.
If the people managing the PAT testing had been properly trained, they'd have known that most of the items which were supposed to be tested didn't need testing in the first place, and were more likely to be damaged or rendered less safe by testing by unqualified testers.
Could you explain that difference for those of us less knowledgeable please Andrew?
One is small, the other big! Alan.
;-)
Do you remember Ohm's law, linking voltage, current, and resistance? In honour of Mr Ohm, resistance is measured in Ohms. A milliohm is 1/1000th of an ohm. A megaohm is a million ohms.
Resistance of conductors is low, and typically quoted in milliohms. Resistance of insulation is high, and typically quoted in megohms. Hence the relevance to understanding PAT test readings, and being able to verify them against permissable values and track changes.
Thanks. So the important thing is the underlying knowledge, rather than following the instructions parrot fashioned?
You can do either - provided that you're a competent parrot and do follow the flowcharts of which particular tests to run, and which not to. A failure with poor quality PAT is when the tester carries out just the same process on both kettles and electrocardiograms. A tester that _can_ apply a huge voltage or current for a test doesn't mean that such a test _should_ be applied to sensitive equipment. However (as mentioned above) the huge "boot up the arse" test is often one button press, the less aggressive test requires manual work and testing more gently section by section. That takes longer and you're paid the same, so guess which is favoured? Equipment that is destroyed under testing was "obviously faulty" so it's rarely a problem for the tester.
Most PAT work is done in offices and it's testing IT kit (the most who'll pay for it, and who have the most kit). Given the short lifetime of such kit anyway, the most likely PAT detectable faults are misfitted plug cable clamps on the office kettle and wheely chair damage to removable power cords. Both of these ought to be observable visually before you even connect the tester. Yet how often are they?
From the office's point of view, observed cowboy PAT is the best of all. They're not told to replace anything expensive and there's blame management in place if anything does go wrong afterwards.
As to underlying knowledge, then forget it. If PAT is a skill, it's a skill in running a service business (which is a trade in itself). If you can run a business that finds customers and delivers the service to them competently and cheerily, then away you go. It's closer to maintaining the plants in an office (which I wouldn't ever demean - I know I can't do it) than it is to a branch of electrical engineering.
Most PAT people know the difference between "a milliohm" and "a megohm". I've known at least one though that had _no_ appreciation that one was "lots of" and the other "very few" of the same unit. The idea that both conductors and insulators could be measured with the same unit was anathema to them. Another (older) PAT guy knew what mhos and permittivity were too, but he was happy to still have some self-employed job of his own from his redundancy money, as the vast electrical engineering empire he'd been part of had folded in place of call centres and servicing peoples' financials. Surprisingly he wasn't even bitter that his vast knowledge was now pretty much pointless now, realistic enough to recognise this, and cheery enough that his new little business was ticking along, even though it wasn't the sort of engineering he'd been used to.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "The Medway Handyman" saying something like:
This one is near, that one is faaaaaaaaar away.
Think scale.
Milliohms is what you and I live in. Any bugger can walk up tp the front door with little resistance.
Megohms are what the Beckhams live in. Much higher resistance to getting in.
MBQ
And kilohms is where Fred and Rosemary West lived? Easy to get in but very hard to get out with any spark left in you.
Owain
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