said by davidg:if the device's neutral is tied to teh chassis, as many devices are even though they should not be, then it IS a big safety issue due to the "neutral" now being hot.
Connecting the neutral (or any of the hot legs) to the chassis is illegal in both the USA and Europe. It would prevent the device from being listed.(This was not always the case. Older kitchen ranges are an example.)
Appliances must either have a ground pin, connected to the chassis, or be
double-insulated, in which case they do not need a ground connection.
Again, not a factor. Fuse your 240V circuit properly, and have a ball.