PAT Testing Query

[wallyanker]

Hi Guys/Gals

We have had some instant printer photo kiosks delivered and before they can be sent out, they have to be pat tested.
Our PAT tester has failed them because the earth continuity test using the croc clip on the metal casing of the machine measured 0.25 ohm. PAT tester says the limit is 0.1 ohm.
If this is true, can you advise of any way to reduce this figure to within the 0.1 ohm limit please?

Thanks

 

[stef]

Hi Guys/Gals

We have had some instant printer photo kiosks delivered and before they can be sent out, they have to be pat tested.
Our PAT tester has failed them because the earth continuity test using the croc clip on the metal casing of the machine measured 0.25 ohm. PAT tester says the limit is 0.1 ohm.
If this is true, can you advise of any way to reduce this figure to within the 0.1 ohm limit please?

Thanks

check terminations of CPC of that photo printer, also the bonding to the chassis. How long is the lead?
If it is a long lead you have to calculate the CPC conductor length in. Make sure that the test clip has proper
contact tho exposed metal parts and make sure that the test leads are nulled!!!

 

[Adam W]

What test current are you using?

 

[wallyanker]

Power lead is a normal 1 meter 3 pin jobbie, same as a computer lead/kettle lead etc. From the other side of the plug in, a wire of approx 1.5mm about 5 inch long bonds to the chasis. Doesn't matter where you put the croc clip on the chasis, readings still above 0.1 ohm. Will double check he has zeroed <--- not sure thats a word. lol. the leads.
Thanks

 

[wallyanker]

What test current are you using?

not sure, he said he has selected the pc mode on the tester (kiosk is basically a pc inside)

 

[Adam W]

Call me a cowboy but personally I would just pass it and move on - 0.25Ω isn't that far out anyway. It's certainly not an open circuit and as already mentioned you need to take the resistance of the wander lead into consideration plus the resistance of the connection between the clip and the casing.
If you tested it at 25A I'm certain it would fall within the limit, although I wouldn't try it if there is a computer inside.

 

[rodney12]

I'd have imagined he would have tested at 100mA if in IT mode.

TBH I would have passed them as well, did he test the kettle lead seperately? and if so what was the reading on? cause you could take that figure off the 0.25, most kettle leads I test tend to be around 0.08 ohms anyway

 

[wallyanker]

He has tested them at 200ma, the pat tester asks you the length and csa of the power lead and automatically makes allowances for it.

i have passed all the information on you guys have said and i think he is going to let them go...

Thanks to all who responded

 

[nickblake]

Probably on some paint ,if the panels are painted befor they are assembled the this could cause this normally when ive tested them they are around 0.09 , test them at diferant points IE the base

 

[cbw]

I wouldnt just pass it.

If the lead can be removed then it can be adjusted if not its a fail, and it has failed for a good reason, what will it be like next year/2years down the line.

Regulations are there for a reason, this is a clear fail, if you want to be Mr Wayne that is your choice but I think your a FOOL if you make up your own rules and regulations.....Its fine to drive at 40 in a 30..................

 

[Liberator]

Hi Guys/Gals

We have had some instant printer photo kiosks delivered and before they can be sent out, they have to be pat tested.
Our PAT tester has failed them because the earth continuity test using the croc clip on the metal casing of the machine measured 0.25 ohm. PAT tester says the limit is 0.1 ohm.
If this is true, can you advise of any way to reduce this figure to within the 0.1 ohm limit please?

Thanks

Test the lead on 25A continuity setting, this will burn off any grease/furring around the copper conductor and descrease the resistance.

Then when the Power Lead has tested and being passed at probably 0.06 Ohms test the lead and appliance together but on a lower earth setting like 100mA.

You should allow approx 0.1 Ohms per 3'/1metre of cable and 0.1 Ohms for the appliance itself, allowing max 0.2 Ohms, so it wasn't far off that anyway.

Check the Earth pin on the plug, if it has turned brown over time, take a file and clean the earth pin up ensuring any metal filings are completely removed. This can lower the earth continuity also.

Another thing maybe to ensure that the PAT tester is calibrated, and that its own socket is clean and free of debris.

~Liberator.