How do you PAT test a laptop charger? Lots of varying opinions so lets talk about how I believe they should be tested. PAT Testing of a Laptop charger.
A word about that functional earth, if you are using a laptop to play music into a DJ mixer, the functional earth type of power supply stops a hum sound from coming through the speakers. If your power supply is like the one without any earth, you need to use external hum filters on the audio leads . If I PAT test a laptop power supply, I do visual inspection to ensure there is no damage to the casing and do visual and continuity/insulation checks on the lead if it's a detachable lead type.
Hi John, it all depends on the charger. I have a Lenovo class 2 charger with no functional earth and I don't get any hum through my audio equipment. I get most hum from chargers with FE that are faulty or poor quality.
@@caterhampattesting I had a laptop with just a figure 8 mains lead and I had to use hum filters when I used it with my disco gear. When I got a new Acer laptop with FE and the clover leaf lead, there was no need for the filters. I get your point though , places like ebay are full of poor quality cheap replacement parts and these are often nowhere near good enough but try telling the public who just think more expensive approved parts are a rip off.
We need a brand new equipment design just for Laptop PSU testing. I work at a recycling company we have hundreds of PSUs with hundreds of different V/A, many have protection circuits from which there is no current unless it is plugged into the laptop. The voltmeter becomes useless.
There what we call 3 pin out put you will see a outer ring a inner ring and a center pin. Dell and some HP use this. The center pin is not for output voltage the inner ring is the + side. The center pin detects it is plugged in.
When logging test results would you enter as 2 separate entries, one for cloverleaf cable and then one entry for PC (being tested with the cloverleaf power cable)? Or just the results for PC as this will have been tested with the same cloverleaf power cable assuming the cable passed.
I looked at power adaptor which the customer had taken apart and reassembled but with the copper screen enclosure inside the insulating cover and directly touching the pcb. The result was a direct short from the live to the barrel connector. Surprisingly it still worked and made the metal casing of the class 2 item, in this case an electronic piano/ keyboard live. Very dangerous and would have gone undetected if the customer's RCD hadn't tripped. I guess it's unlikely to find again but maybe a continuity test between live an neutral to the barrel might be worth doing when looking at these adaptors..
great point, this was actually discussed by various authorities when developing the new code of practice and the opinion was that whilst you could do a test like that it was deemed unnecessary.
Having watched a recent Seaward webinar on FE appliances, I was of the opinion that these weren't a visual only or class 2 test and should be tested as a class 1 with a long press on the test button (5th edition testers only) after the earth fail in order to test the resistance and leakage current in the correct manner
Hi, I have ordered the 5th edition of the code of practice and it has turned up as a spiral bound folder book, is this right or is it a copy/duplicate, how does it normally come please help and advise????
@@caterhampattesting Thank you for confirming that, I thought it was a copy but I had not seen the new book untill looking at your video, I can now clearly see the book is like all the other previous versions and not spiral bound. I managed to get the money back through PayPal and have reported it as copyright infringement, thank you again Ben.
because there is electrical separation between the mains voltage and low voltage side. you can't carry out any test on the DC jack that will give you any meaningful result
@@caterhampattesting I disagree, I've not found one yet that the outer barrel isnt connected to the earth. I always do a continuity test as belt and braces.
There are lots of ways, either by being self employed or working for one of the many National or regional testing companies. Get yourself in some of the Facebook pat testing groups
There is a problem with cheap or fake chargers, especially phone chargers. Many are unsafe by design, with inadequate creepage/clearance distances and standard capacitors instead of Y1 rated capacitors between mains and DC output. Other dangerous conditions can be caused by hidden physical damage, including water ingress. If the output is earthed, then the resistance to mains plug earth should be checked. If not then the leakage current or insulation resistance should be measured, with the DC plug as an exposed metal part. A visual only inspection is totally inadequate.
See, I do disagree with you there. There is no meaningful test that a regular PAT testing machine could carry out. I would be interested to know what exact test you would do, what readings it might give and then how to interpret them. The job of a PAT tester is to ensure that the appliance is as safe as the day it was manufactured. There is no possible way we could determine (on a charger or any other piece of equipment) what creepage is used or what type of capacitor - that simply isn’t for us to check as a PAT tester.
@@caterhampattesting If an item with an built-in switched-mode power supply is tested, then why is an item with an external PSU not tested? Construction of cheap PSUs is haphazard with many transformers relying on only the wire enamel to separate mains and output. If these products were type tested they would certainly fail the high voltage isolation test, but they are imported with no checks. Whilst PAT can't be expected to perform the same function, it could well detect some of the most dangerous items, by testing insulation resistance between output and input (L and N linked,
@@dino6627 I do understand what you are saying but please could you talk me through the exact process that you would test a laptop charger for example with your PAT machine.
From some one that repairs charges and been inside over 100 of them. Some tests must be done. For leakage as if there has been a power spike the filter capacitors can go short circuit. And high voltage can then end up on the end of the charger also if it has been dropped and the earth connection is damaged the same can happen. Some to have the neutral side of the charge lead attached to the earth / CPC I test by continuity from the earth pin mains side to the laptop charging side. Also do a test by plugging it in and checking for voltage from the neutral side to a known earth. It is only when you look inside and repair them you would know the dangers and what to test for. Also link live and neutral together and apply insulation testing from the two pins to the outer neutral side of the charge lead. Also test the output voltage with a good voltage tester. There is a lot missing for this video like the others. Sparks go about it the other way the right way.
I do understand what youbare saying but this would not fall under the role of a PAT tester. All of those checks that you mention could not be done by using a basic PAT testing machine. Nor are any of those tests mentioned in the IET code of practice. It is not under a PAT testers remit to take an item apart and check the internals. There is nothing missing from this video in terns of what a PAT tester should be doing.
@@caterhampattesting they should be in there. As a basic test just looking at it is no use. Try some your self link each pin and do a test on a number of chargers. The books I have read have been zero use. When there is internal damage from being dropped or power spike.
@@caterhampattesting as a electrical engineer I have to test after service I see people in offices with a clip board going round testing and failing working stuff. My head hurts trying to show them. I have been out to were av equipment is being rented out the guy was sent on a course for pat testing. He could not find the earth point to test from.
