Online assistance for electrical trade people in New Zealand and Australia Login  |  Register  |   Forgot Password
Assistance for electrical trade people




Click here to send Forum Admin a pdf document for publication on this Topic

Documents must be less than 200k in pdf format

Posted By Topic: Do I need a PAT testing machine?

Sep 26 2019 17:29

Hi guys,been a while, hope you're all good.
Just a quick question about test and tag.
A mate of mine who runs an asbestos removal firm has asked me to do his test and tagging for him. Can I use my multifunction tester to do insulation resistance/earth continuity etc or do I have to have an actual PAT testing machine? I'm happy to help him out but don't want to potentially end up in trouble for the sake of a favour...

Cheers in advance!

Sep 26 2019 17:40

You don't need a PAT.
But you might need more than an MFT.
Any appliance that has eg a relay in it can't be IR tested in the usual way, so you need a meter than can measure leakage current while it's operating.

Sep 26 2019 19:12

I've been considering whether the easiest way to do this might be to just use an isolating transformer, and megger from the secondary to earth/case...

Sep 26 2019 20:20

"A mate of mine who runs an asbestos removal firm "

Make sure they do a through decontamination before you handle their gear, if items don't need to be started up to test, suggest you don't run them.

I'd wear a mask and gloves in any case, and if you have any doubts about the way they operate, back out fast.

Sep 26 2019 20:57

Cheers for the replies guys.
Hmm yeah forgot about the earth leakage measurement...I rarely do any test and tag apart from putting a sticker on my leads every 3 months after a quick visual like we all do lol!
Thanks for the concern, Asbestos isn't to be taken lightly but my mate is legit, been in the game a long time and not a chancer...I'll still wear a mask and gloves though 😜
The isolating transformer idea is an interesting one, although you can buy earth leakage clamp meters on eBay etc for reasonable money. Maybe time to add one to the toolkit!


Sep 26 2019 21:31

Take a look at 3760 Fig E2. You can easily make a differential tester.
I made one using a CT out of an RCD, and connect it through the mA scale on my DMM.


Sep 26 2019 21:55

That's interesting to know DougP. I'll dig out my copy of 3760 and have a look...
I'm sure there's a few different ways to skin this particular cat!
I remember being told you can use the ramp RCD test on an mft to determine the leakage current of a faulty appliance plugged in to a socket with a proven good RCD upstream...Haven't tried it personally mind..


Sep 28 2019 23:10

Your general multi meter or clamp wont have low enough scale to accurately read the mA. Best will be a low scale mA meter with accuracy required.