Our Voltimum Experts answer your questions on a daily basis in our Technical Expertise area. This one, concerning Class 1 equipment identification – in this case an iron - is answered by SELECT:
Figure 11.1 shows what I would call the 'traditional' arrangement for a Class 1 piece of equipment. However, illustration 11.3 shows a different arrangement whereby the base of the iron is 'unearthed metal'. The description for this is: "A continuity test to this 'unearthed' metal may give a misleading result".
My question is - how would you identify that one had this type of iron as opposed to the type in illustration 11.1?
I am only guessing, but perhaps one can physically see that there is an insulating material above the iron base plate, but I am not sure - so I would appreciate any advice you could pass on.
Answer: Good question! - I do not think you would be physically able to see this unless opening up the equipment, which I do not think is appropriate when PAT testing.
I think a more realistic approach is that of having identified the equipment as Class 1, you then try to obtain a satisfactory continuity reading from the exposed metal parts. If the part is insulated from earth and no resistance is obtained - resulting in a doubt as to the product's safety, then perhaps, the manufacturer should be contacted for information.
11.1.4 shows unearthed metal in casual contact with earthed metal and, in this case, a continuity reading may be obtained - but it may be slightly higher than what would normally be expected. Again, if in doubt I would recommend contacting the manufacturer of the equipment.
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