The risk you run by not connecting Earth is DEATH.
Some appliances are double insulated - no external parts can possibly become live so they have only two wires in the cable.
If there's an earth wire or terminal it should always be connected.
My Brother in Law borrowed a metal lead-light that should have been earthed but wasn't. He went up into a loft with the working but faulty light and touched the water pipes and was electrocuted dead. The casing of the lamp was live but he couldn't tell until he touched earth.
Peccavi
March 2009
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