By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th

PAT - Portable Appliance Test

All Topics | Latest Posts

Search for:  in Thread Title in  
Speedy Builder531/12/2020 15:19:52
2498 forum posts
196 photos

Can a PAT test cause a washing machine logic board to fail?

I had a BECO washer dryer machine which was only 4 years old. Straight after it was PAT tested, the machine was "dead". When the repair man came, he said the main logic board was shot and would cost £280 to replace it, he also said that this was the 8th Beco machine he had visited recently with the same fault (He didn't comment on PAT testing).

Obviously, anything is possible, but could a PAT test cause this failure ?


old mart31/12/2020 15:31:02
3497 forum posts
216 photos

PAT testing is not usually ever done on home appliamces during their lifetime. If you were to buy any mains electrical equipment second hand from a shop or charity, it would have to be tested first. We have hundreds of things PAT tested every year at the museum, and the only variations to the basic tests are for computers. We have not had any particular failures caused by testing that come to mind. Most failures are damaged cables and plugs. The VFD for the mill was tested this year and wasn't damaged.

Bad luck with your machine, the prices of new machines being low at the moment may make you think twice about the repair to yours.

Edited By old mart on 31/12/2020 15:33:11

Edited By old mart on 31/12/2020 15:34:41

Edited By old mart on 31/12/2020 15:37:32

Robert Atkinson 231/12/2020 15:34:15
1151 forum posts
20 photos


Yes, it could depending on how th test was conducted. In this case it is highly likely the PAT caused the failure because of the timing and type of failure. It is difficult because for safety, as water is involved, the washer really needs a full insulation test, but that is the test that can damage electronics.
Did the PAT operator not make sure it was working pos test? I'd contact them and at least try to get them to pay for the repair. However they probably have a clause in therir tems that removes responsibility. This may be unfair contract bu cetting resolution is another matter.
Why was it PAT tested, a rental property? If so it's a commercial arrangement and you have no consumer protection. Unfortunate combination of poor design and bad testing. Contary co common ideas ther is NO legal requirement for PAT, the requirement is to provide safe equipment. If tool passed test yesterday and electrocuted someone today the employer is still guilty. The PAT reduces the risk, but not liability. The main thing enforcing PAT is insurance requirements.

Robert G8RPI.

Michael Gilligan31/12/2020 15:35:01
19578 forum posts
995 photos
Posted by Speedy Builder5 on 31/12/2020 15:19:52:

Can a PAT test cause a washing machine logic board to fail?

I had a BECO washer dryer machine which was only 4 years old. Straight after it was PAT tested, the machine was "dead". When the repair man came, he said the main logic board was shot and would cost £280 to replace it, he also said that this was the 8th Beco machine he had visited recently with the same fault (He didn't comment on PAT testing).

Obviously, anything is possible, but could a PAT test cause this failure ?



Very possibly, Bob

When I was at BAe [20+ years ago] they flatly refused to PAT a lot of computer equipment for that very reason.

... Probably depends on the characteristics of the test-set



Edit: Robert posted whilst I was typing.

Edited By Michael Gilligan on 31/12/2020 15:36:40

Oldiron31/12/2020 15:43:14
907 forum posts
40 photos

Yes it could. Over the years I have seen PC's, Monitors, Electronic calculators and £25000 robotic reciprocating powder coating arm that would not run after a PAT test. Difficult to prove that it was the test that killed them though.

I presume that the washer is in an indusrtial setting as home appliances are not liable to be PAT tested

Take your board to a local TV/PC repair shop, they may be able to change the duff component much cheaper that a replacement.

Best thing to do to stop it happening again is to wire the item direct to an outlet. ( no plug) It is then not liable for a PAT test.


Clive Foster31/12/2020 15:43:35
2988 forum posts
105 photos

Depends on the tester used and the person doing the job.

I know its possible.

Back around 2000 I had a very expensive laser PSU killed by a ignorant contract PAT testers along with several other bits of sensitive electronics driven out of specification. Numpities also pulled off all the IEC connector power cables, dumped them in a pile and tested the whole lot. I was not amused at having to sort the right leads with the right fuses out afterwards. Nor by having to spend a couple of weeks to re-align some optical test equipment they had moved.

Got into serious trouble for throwing them out of the lab the moment the yobbish tendencies were revealed but was vindicated by the trail of havoc left in the other labs. Next time round supervision was enforced rather than accepting the contractor demands thta they should have undisturbed access.


Thomas Cooksley31/12/2020 15:48:45
55 forum posts

Hi everyone,

Bob the answer to your question is yes. A standard PAT test includes an insulation resistance test at 500volts DC this is quite capable of frying any electronics.

For that reason we deleted the insulation resistance test for any equipment that had electronics inside, such as: radios, televisions, computers and inverter speed controlled machinery. To name but a few. Sorry to hear about your washing machine. Tom.

Frances IoM31/12/2020 16:02:42
1195 forum posts
28 photos
I bought a spare controller board for a washing machine for ?1 at an auction as it had 5 5v 10A relays on board - the logic to the microprocessor and display was direct from mains derived from the high voltage circuit to drive the light behind the display - a 500V Pat test would fry everything on that board
Grenville Hunt31/12/2020 17:18:42
26 forum posts

I think it would be most unlikely that PA testing could have destroyed the circuit board unless as Michael stated "depends on the test characteristics" most modern approved PA test sets short together live & neutral and apply a 240v test between this connection and ground, the 500v test being used for 3 phase equipment, some of the very old sets did use 500v with mixed results, if the service engineer in the OP had eight failures in a short time this to me would point to a design failure unless all eight had been tested with the same PAT machine,


noel shelley31/12/2020 17:29:27
1008 forum posts
19 photos

One case I saw was a guy with no electrical knowledge sent on PAT test coarse multiple choice questions and a "helpful tutor" and passed. He wrecked no end of gear and appliances. For example earth bond test, current used 25A on .75mm wire, needless to say they all failed test. As a rule never test anything with electronic circuits for earth leakage at high voltage. Noel.

duncan webster31/12/2020 19:38:06
3702 forum posts
69 photos

As Robert says there is no legal requirement for PAT testing, it is a knee jerk solution to the requirements of I think PUWER, Provision and Use of Work Equipment regulations, which requires that electrical equipment is safe. I think it's stretching reason to call a washing machine 'portable'. If a power lead has damaged insulation such that the conductors are exposed but not touching it would still pass the box of tricks test, and I've seen the chaps where I once worked just plug it in, press the button, sign the form, no attempt to inspect the cable. For regularly used portable gear in an industrial setting regular inspection of the cable, just looking at it, is much more sensible, after all the likely failure is damage to cable or coming loose at the plug.

If Grenville is correct, and I've no reason to doubt it, most modern double insulated stuff would pass no matter what fault it had. I did once ask why the chap was checking the live-earth on a cable with a plastic earth pin

Nick Clarke 331/12/2020 19:59:27
1318 forum posts
53 photos

I don't know if a PAT test will damage a domestic appliance, but I do know that the washing machine and the dishwasher in the school Food Technology room next to mine are tested each year like everything else and I have have never heard of a problem in the 10 years I have been there.

Emgee31/12/2020 20:40:08
2311 forum posts
277 photos

As others have said it is possible that the electronic board was damaged by careless testing, but if it was a full test using an automated instrument normally the final test in the program will be a RUN test which records current or kVa and any earth leakage current so there will be a recoding of the test retained in the meter under the Item Id and Location ID for the tested address.

Ask the person/firm that conducted the test for a full report of the readings obtained to check if the run test is recorded, at least it would show the appliance still functioned after the test was carried out.

If the appliance was checked with a Pass/Fail type of instrument then the details listed are probably not available even if a Run test was included.

If as suggested the Washer is connected to a SFS to remove it from a PAT if the property is rented all electrical equipment needs confirmation that it is in good safe working order so the washer will still need inspecting and testing as fixed electrical equipment.


Speedy Builder531/12/2020 21:26:51
2498 forum posts
196 photos

Thanks for all the ideas and responses.

looking at the test report, the equipment was a MEGGER 1720 and the test result was a pass at >20M ohm for Wash m/c class 1

If nothing else it will provoke me to ask some more questions of the tester.


KWIL31/12/2020 21:51:59
3473 forum posts
66 photos

I would consider a Megger 1720 would be used for IEE 18th Edition Regs testing and NOT as a PAT tester. Megger make a PAT specific tester.

Thomas Cooksley31/12/2020 22:12:42
55 forum posts

As KWIL said a Megger 1720 is a installation test meter not a PAT. Why was the tester using the Megger and not a proper PAT tester? Tom.

Sam Spoons01/01/2021 00:28:14
94 forum posts

As above, PAT testing is not a legal requirement and the tester does not need a qualification. The requirement is to be "a competent person" but the easiest way to prove that should a claim ensue is by having a certificate and, more importantly, good records.

WRT the plug in and push the button brigade, the visual inspection is every bit as important as the actual test and reveals 80% of failures even before the device is plugged in.

Phil Whitley01/01/2021 15:40:49
1394 forum posts
147 photos

Pat testing is generally a scam carried out by largely unqualified people who have attended the 12 hour course offered by some training establishments, to make money.Other than this course there is no requirement for the tester to have any other relevant qualifications in any field. It applies to workplace only, and there is no requirement for appliances in the home to be tested. If you are in or run a business that has to have PAT testing done, far better to go on the course, buy a tester and do it yourself. Given that a "portable appliance" is

An appliance of less than 18 kg in mass that is intended to be moved while in operation or an appliance which can easily be moved from one place to another, e.g. toaster, food mixer, vacuum cleaner, fan heater.

Why would you test any washing machine?

Emgee01/01/2021 17:30:00
2311 forum posts
277 photos


If Class 1 equipment one reason would be to confirm the earth conductor is connected from the plug to the machines metal frame and has a suitably low resistance.


noel shelley01/01/2021 17:49:41
1008 forum posts
19 photos

Speedy, why was the pat test done ? It seemed like a good idea or legal requirement? As others have said Yes an improperly carried out test would blow the board. Sheilded pin plug correct fuse, sound lead, earth bond. No flash test. I would be thinking of claiming against the testing person or firm. It sounds as though a flash or insulation test was done. Noel

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Support Our Partners
JD Metals
rapid Direct
Eccentric July 5 2018
walker midge
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest