"Josh" wrote in message
...
But is that circuit correctly grounded, is it?????

When I bought the 50s vintage house in 1971, all the outlets were the
old 2-prong type. The only ground was outlet ears and/or outlet
mounting screws into the metal outlet boxes and back to the breaker
box via the flexible armored steel conduit. Over the years I've
replaced all the outlets with 3-prong type, drilled a hole in the back
of the outlet box for a sheet metal screw, and connected a 6 inch
green 12 gauge wire from the screw to the outlet ground connector.
That's the case with the garage outlet I'm modifying from single to
double.

If I use an AC voltmeter or a small neon circuit tester to measure
from outlet hot to neutral, it naturally reads approximately 117 v.
If I measure between the outlet hot to the metal outlet box, or the
ground connector on the outlet, it reads the same 117v so I know the
ground path is in tact all the way back to the breaker box.
Fortunately, none of the previous owners replaced any of the metal
outlet boxes with the blue plastic ones! I've never figured out why
anyone would want the plastic boxes but I guess that would be a
completely new topic/thread.

Plastic boxes can be bought in large 22 cu. inch size for about 1/4 of the
price of a standard 2x3 steel box. More room, for the buck, less chance of
cutting a conductor and having it ground out, but you cannot feed a plastic
box with a metal conduit, which may be the reason previous owners didn't