EN60065 & PE leakage

[tomizett]

Hi All,
Boring work question.
Does anyone know if EN60065 specifies a maximum protective-earth leakage current and, if so, what that value is?

Of course, the standard is not publicly available, and a quick bit of googling has not turned up anything useful. I hoped this might be something that some members who have done product design might be familiar with.

The background to this is that I was recently brought some equipment which had "delivered an electric sock and failed a PAT earth bond test". I've found nothing wrong with it - I suspect that the complainant may have a poor earth at their site, and simply had a hard time getting an earth bond on the painted and anodised surfaces.

The leakage current is high, however, at 1.3mA. This is not surprising, given that it has three stages of EMC filtering, but is a little unusual. I'd like to be able to re-assure the concerned parties by saying "I have tested it and it meets the manufacturers specs". However, the manufacturer is not able to provide a leakage figure... they just say "it meets EN60065". Hence my question...

Thanks for reading.

PS.
If I've not looked in the right places, and this information is actually published somewhere, please feel free to point me in the right direction.

 

[unclejed613]

If I've not looked in the right places, and this information is actually published somewhere, please feel free to point me in the right direction.

it actually is published somewhere, it's just hidden behind very big paywalls. this is one of my "internet pet peeves"... there was a time, that if you wanted to look up one of these standards, you went to a library. if they didn't have it there locally, they could usually get it for you. often, because it was "reference material" you couldn't take it home, or you could only borrow it for 3 to 7 days, so you made notes, copied some pages from it, or whatever. i would have thought standards, like other governmental documentation are public domain.

 

[Nigel Goodwin]

The background to this is that I was recently brought some equipment which had "delivered an electric sock and failed a PAT earth bond test". I've found nothing wrong with it - I suspect that the complainant may have a poor earth at their site, and simply had a hard time getting an earth bond on the painted and anodised surfaces.

The leakage current is high, however, at 1.3mA. This is not surprising, given that it has three stages of EMC filtering, but is a little unusual. I'd like to be able to re-assure the concerned parties by saying "I have tested it and it meets the manufacturers specs". However, the manufacturer is not able to provide a leakage figure... they just say "it meets EN60065". Hence my question...

Assuming it's a class I device?, then the PAT test should pass the earth test, if done properly. A 'poor' earth at the site hasn't any relevance to the test as it's not referenced to earth at all, merely a high current resistance test between plug earth pin and any exposed metal surfaces - the unit under test isn't plugged in, and isn't powered. I presume you have a PAT tester?, and have checked the earth resistance is OK?.

My PAT tester is only a simple one, but it can be set for either normal or long mains leads (to account for the added resistance of the lead), it also has a button you can press (whose name escapes me at the moment - and the tester is at work, so I can't check) - this is essential to test microwave ovens, whose mains filtering components cause them to fail otherwise. I presume it increases the acceptable leakage level to allow testing of mains filtered units.

If they claim to have received a 'shock' (not a sock?) from the unit, as you say it could be that the socket it was plugged into had lost it's earth, and the leakage through the filters could give you a 'tingle' - hardly a 'shock'.

Another obvious option is that it was a static shock, and that the recipient was charged up - and discharged via the earthed appliance.

 

[tomizett]

Oh dear... yes, I did say "electric sock".

Nigel - I think my first paragraph was a bit misleading.
As you say, a poor site earth would have nothing to do with a failed PAT. The person who reported the fault put it on their tester and failed to get a good bond; when I did the same with my identical tester, after verifying the internal earthing visually, it was fine. However, in order to get the good bond to the chassis I had to put the earth clip on a screwdriver and press that firmly into a screw head - so I suspect that the original tester had simply failed to find a clean bit of metal.

and the leakage through the filters could give you a 'tingle'

So, yes, that's what I was trying to get at. "Touch current" is the phrase, if I remember correctly. Certainly not dangerous, but in my experience people tend to find it very disconcerting.

If I disassembled the item and took a look at the Y capacitors, I could calculate the expected leakage and answer my own question. It's just that that's quite a lot of work.

Regarding high-leakage devices, we removed leakage current testing from our PAT regime for just that reason - there is some gear that simply will not pass, by design.
The normal threshold for earth leakage is 0.75mA whereas the item in question passes 1.3mA - which is why I was a bit surprised that the manufacturer couldn't come back to me with a number. It's the kind of data that would matter to anyone installing these devices, so that they could size/arrange their RCDs appropriately.
Anyway, no matter.

Jed -
Yes, it's a peeve of mine, too. I understand that coming up with standards is a costly process, but it irritates me how expensive they are to obtain, and how jealously guarded they are. Especially when it comes to matters like this, that concern safety. After all, surely if I am sold something that is supposed to meet a particular standard, it would seem reasonable to be able to find out what that standard means.