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Mobile,laptop and cordless tool chargers

PostPosted: Wed Apr 29, 2015 10:10 pm
by Bigaki
Hi, I've just started pat testing and I'm waiting to go on a training course. I've been shown how to pat test several class 1 and class 2 items from a colleague at work, but when I ask him to show me how to pat test mobile phone, laptop chargers and cordless tool chargers he tells me you only do a visual on them. This can't be right surely? Any help on this would be appreciated.

Re: Mobile,laptop and cordless tool chargers

PostPosted: Thu Apr 30, 2015 5:45 am
by Alan Freeman
Class 1 chargers should have continuity to the DC plug, so clip your earth lead there.

Class 2, again clip your earth lead there as the only metal part!!

Re: Mobile,laptop and cordless tool chargers

PostPosted: Thu Apr 30, 2015 7:42 am
by southseas
Where are you going to be testing items? In Aus & NZ , under AS/NZS 3760:2010 - items with detachable leads under our T&T Standard have their lead tested as a lead, then lead plus associated power supply tested as an appliance of the appropriate Class.

Re: Mobile,laptop and cordless tool chargers

PostPosted: Thu Apr 30, 2015 10:51 am
by Patnik
Alan Freeman wrote:Class 1 chargers should have continuity to the DC plug, so clip your earth lead there.

Class 2, again clip your earth lead there as the only metal part!!


Unfortunately the vast majority of Class 1 chargers we see don't have earth continuity to the DC plug by design so it can't be tested. We just mark these as 'no accessible earth' on the test record.

Re: Mobile,laptop and cordless tool chargers

PostPosted: Wed Sep 02, 2015 8:47 am
by Ford Prefect
I know this is an old thread but a quick question on class 1 power adapters?

After a discussion with a fellow PAT tester in another building -
If you do get a viable earth reading at the "DC" end, even if it's close to the pass/fail limit, do you then plug the adapter into the unit it's supplying and continue the test on that item? which 95% of the time will fail because of the presence of the adapter, one of us said yes the other said just do a visual.
If it helps the item that caused the discussion, was a sound desk with a 5pin DMX.

Cheers,
FP

Re: Mobile,laptop and cordless tool chargers

PostPosted: Wed Sep 02, 2015 6:40 pm
by Alan Freeman
Any equipment supplied via a PSU is low volt, and therefore not in the remit for PAT.

Test the PSU in the normal way and label it up. The equipment does not need a label..

Re: Mobile,laptop and cordless tool chargers

PostPosted: Thu Sep 03, 2015 8:36 am
by Ford Prefect
Cheers Alan,

That's what I thought but hadn't come across a class 1 PSU before (loads of class 2!!)
Thanks again for clearing that up.
FP.

Re: Mobile,laptop and cordless tool chargers

PostPosted: Sat Sep 12, 2015 11:28 pm
by grantsonuk
I have a vague memory from the pat testing course , some chargers/psu's which theoretically class one or just not marked as class 2 have the earth wire connected to a metal can surrounding the transformer coils to help with shielding from interference?