On 07/07/2010 02:04 PM, Josh wrote:
Since there is wire installed, all he has to do is pull one wire and measure
it and pick up the lengths and colors (& sizes) he wants at the home depost
or whatever.


I'm the original poster, OP. Just to clarify:

The flex metal conduit is attached to the garage outlet box and to the
breaker box. It has the hot green wire and the white neutral wire
inside.
The green wire is attached to the breaker, and the white wire to the
breaker box's neutral& ground bus bar.

I would consider disconnecting the green wire from the 20A breaker and
pulling it through the conduit, with a proper replacement black wire
attached and trailing if it were a straight run from the breaker box
to the garage outlet. But since there are living room outlets also on
this circuit, and they are NOT fed from the garage outlet box, there
has to be a junction box in the wall or attic between the breaker box
and the garage outlet. Therefore, I can't pull the entire wire
through without gaining access to that hidden junction box, and
unhooking the wires (probably green also!) which are feeding those
other outlets. And due to the VERY small crawl space& loose
insulation in my attic, I'm not going up there. Based on my own
intuition and the opinions of other posters, I'm simply going to mark
each end of the existing green wire black, post a warning inside the
breaker box that there's one green wire that's hot, and leave it
alone.

As for the questions about whether the circuit is properly grounded, I
would assume the short green grounding wire from the new outlet to the
screw in the metal outlet box, and the metal conduit from the outlet
box to the breaker box should be adequate. I measure 117 VAC from the
outlet's hot wire to the outlet box screw, which to me means the
ground path is intact.

One question I do have is: Can I just use a black magic marker to
paint the ends of the green wire or do I have to use, as others
suggested, black electrical tape?



That depends on your personal comfort level. NEC says "no."

Personally if I were to repull wire I would pull an add'l conductor
through for a definite ground as per modern practice, assuming that
there is enough room to do so. I'd pull out the green and pull another
green and a black or red behind it. If you're "frugal" you could pull a
black and a string through with the green, then pull the green (and
another string just in case) back in with the string.

nate


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