Greg G. wrote in message
...
larrymoencurly said:

VWWall wrote in message
nk.net...

Many modern drills are "double insulated", and hence don't require a
grounded body to be safe, so a two prong plug is OK.

I see many power tools with large areas of exposed metal on the
outside, yet they're still classified as "double insulated." How can
this be? For example, corded electric drills are often aluminum in
the front 2" of the body, circular saws almost always have a metal
blade guard, and in both situations this metal is in direct contact
with metal parts of the motor.

Double insulation refers to the fact that the armature has two levels
of insulation - the windings are insulated, and the bobbin that the
windings are on is insulated from the motor shaft with an epoxy insert
that provides an additional layer of insulation. Generally, the
brushes and wiring are also contained in a plastic housing. The metal
portion principally houses the reduction gears and bushings/bearings.

And of course it's all hermetically sealed such that when you drop it in
salt water no current escapes...I didn't think so. Use a third ground wire.