class 1 equipment with no exposed earthed metal

hillbillie · Dec 11, 2010

How do you do an earth bond test for these? I have re read the IEE code of practice on this but I can't find an answer apart form: "...can give misleading results"

For example a class 1, totally plastic vacuum cleaner, at least on the outside (it has tiny metal screws not screwed into earthed metal). If there is nowhere to stick your lead can it be tested? Should I just do a visual and the insulation resistance test?

Adam W · Dec 11, 2010

There's sometimes a little hole where you can poke your probe

.
The 'by the book' answer would be to contact the manufacturer to find out how it's supposed to be tested, but personally I would just do the other inspections and tests.

Patman · Dec 11, 2010

Also think about AC adaptors or power supplies, some of which have no earth connected - even at ther output terminal - yet are constructed and fed with a dedicated IEC power cord.
In this case the earthed power cord is used to provide an earth for the correct fuctioning of the internal electronics and not to provide a CPC.

In this instance Adaptor is tested as Class II and power cord separately as IEC (extenion lead) and a note made to that effect.