Class I device with unearthed metal

[Topquartz]

Evening all; I have just completed the C&G 2377 PAT test exam and now getting to grips with testing in the real world. The IET code of practice shows that class I devices can have unearthed metal parts so in the case of our clothes iron how do I tell if there's no earth continuity because it has a break somewhere in the cpc or just because the sole plate is otherwise insulated and not earthed (device not marked double insulated and definitely has earth connection inside plug)? Thanks for any feedback.

 

[Richard Burns]

If there is no symbol then the COP states that it should be considered as Class I, since you have a cpc in the cable then there should be some metalwork accessible that needs to be earthed and if you get continuity to that point then you are OK.

I have found that some almost entirely plastic coated items often need a long probe into the interstices to reach the earthed metal work, a real nuisance.

If there is earthed metal work then you can test continuity from that earthed metal work to the sole plate and see if they are internally connected and this would bypass a cpc break.

 

[Topquartz]

Thanks Richard, I will try again with a finer pointed probe. The detail is appreciated.

 

[GrantsonUK]

I've found with a lot of irons there is a coating on the element which means you wont get a good earth.

Try the very tip in the gap between the sole plate and the body of the iron if you can fit your earth bond clip in there.

I've found a few coffee makers with ceramic heating elements and completely plastic casing, no exposed metal parts Just have to test as class 2 and make it clear in your notes.

The more appliances you test the more of a feel you will get for finding a good earth and sniffing out problem appliances