Cooker Hood earthing ?

[Dazza1976]

Hi,

I fitted a cooker hood for my friend today, and the manufacturers instructions said - WARNING ! This appliance is double insulated, do not earth.
However the casing is metal, and there was a hole on the casing with an earth symbol on it ???
Why have they said WARNING !! ?? surely there is no harm in earthing something that doesnt need earthing ??

 

[Carter]

Would definitely be on the blower to the manufacturer's tech sales team asking for a definitive version of the hymn sheet! Just because it has a metal casing doesn't mean that can't be of double insulated construction or that it needs an earth.
Does the lead in have 3 or 2 cores (ie with earth or without?) If it's 2 core then it's fair to assume it is double ins. If it's 3core flex then do a low resistance continuity reading between the lead's earth conductor and all seperate exposed metallic parts of the casings including isolated fixing screws. (you never know!) If it's earthed then there should be near enough zero ohms between the casing and that earth conductor.

Bringing an earth to an equipment that does not require it can indeed be dangerous. You are effectively importing a potential onto the eqpt that has no business being there, albeit a potential of 0 volts. Once that's in place on the casing you now have another source of and opportunity for potential difference to arise between this and anything adjacent which faults, if a person contacts both simultaneously the difference in potential drives a current through the body and a p!sser is the result!

Maybe they use a common housing for several electricaly different models of that hood that are sold into different markets/countries.

Deffo give the manufacturer what for though about his inconsistent 'destructions' leaflet.