Class 1 appliance with no exposed metal work to connect test lead too

Legh Richardson:

If its a genuine class I appliance then there will be an exposed conductive part available such as, mentioned, a screw head

It may be poorly or wrongly labelled,

There are cases where class II items of equipment have metals bodies....

Legh

Here is hoping soo as otherwise I have little other choice but to fail the item

lyledunn:

The purpose is to establish if the item is safe rather than filling in a box on a test sheet. 

That's my point I can't assure that an item is safe if I can't complete a full test run for the item class hence it must be recorded as a faulty item and marked as failed 

Legh Richardson:

If its a genuine class I appliance then there will be an exposed conductive part available such as, mentioned, a screw head

It may be poorly or wrongly labelled,

There are cases where class II items of equipment have metals bodies....

Legh

That's not necessarily true.


It may only be the motor that's connected in a Class I configuration, for example, either for EMC purposes, or because of static.


There's nothing to stop a manufacturer completely housing a Class I component in insulating material - and either classifying it as Class I, or Class II (if the insulating material meets Class II requirements per the product standard) as they see fit.


If the product is being manufactured in accordance with harmonized standards, there is usually a means of production-line testing the appliance, which would include a test point for the protective earthing circuit. But there's nothing to stop a manufacturer clipping a housing over the top of a tested assembly after the production line test, and I'm guessing that's possibly what might have happened in this instance.

Alex13:

lyledunn:

The purpose is to establish if the item is safe rather than filling in a box on a test sheet. 

That's my point I can't assure that an item is safe if I can't complete a full test run for the item class hence it must be recorded as a faulty item and marked as failed 

I disagree - just because you are unable to test the appliance, because you don't know how to get at the relevant test points, doesn't mean the appliance has failed - it just means it's not been possible for you to test it.


You can't mark it as "passed" - but I also don't think it's justifiable to mark it as "failed" either, just because the person carrying out the test is unable to carry out that test.


About 30 years ago, I had to deal with something for a distraught person who owned their own carpet cleaning company. A PAT test organisation had failed all of their carpet cleaning machines, because they couldn't get earth continuity to the metal casing of the machines, effectively shutting the business down.


With the particular machine, the bit with all the electrical equipment was inside a removable panel on the larger mechanical housing, and the flexible cable came in through the top through a plastic cover.


So, basically, the outer mechanical housing surrounding the equipment wasn't earthed - but it wasn't an extraneous-conductive-part either and didn't need to be.


So, we correctly tested the machines, and all passed with no problem !



It all depends, though, on what (if any) product standards have been used ... and standards change over time. BS EN 60204-1, for example, would now require the outer "chassis" of that particular machine to be bonded to the PE circuit- but BS EN 60335-series, two particular parts of which would probably apply better to that machine, would have different requirements (if one part were used, it would have to be Class II, but if the other part were used, Class I may be permissible, but no requirement to connect metal parts that are not exposed-conductive-parts to the PE circuit).