In the past many tools and appliances had metal cases and they would have a
ground wire connected to the case so that if the hot lead shorted to the
case it would trip the breaker and not shock the user. Well you might say
just connect the neutral to the case and use a polarized plug. Obviously if
the plug is reversed you get shocked or even the neutral is broken, say in
the power cord, then the case is connected to hot through the motor
windings etc.

Now we have plastic cases so this is less necessary but still important with
appliances such as washers and dryers.

Reminds me when I was visiting a friend's new house and checking out the
basement. I noticed the electrical service was grounded to the water pipe
nearby. But the water came into the house in heavy plastic pipe. Friend
called and they put a copper stake in the ground and grounded the electrical
to it.

This is important where we live because of lightning which often hits power
lines.


"PVR" wrote in message
...
In my new condo at the breaker box I note that Neutral and Ground wires
from the house side are connected to the SAME bus. Why is this? Why not
have just one of these at the controlled device? I'm assuming that this is
a kind of fail safe arrangement?

Peter.