On 7/4/2010 16:19, Josh wrote:
My 1950s vintage house has the armored flexible conduit. Most of the
circuits have the standard black/hot white/neutral color scheme. For
some reason, the 20A circuit I want to modify uses a GREEN 12-gauge
wire all the way from the breaker to the hot outlet terminal in my
garage wall...

I've seen similar wiring schemes in 50's wiring in Los Angeles, which
required conduit wiring at the time. Evidently at one time green was
not reserved for use as a grounding conductor. You may be able go
grandfather in what is in place now, but if you're extending the circuit
use another color.

Also keep in mind that flexible conduit is not suitable as a grounding
conductor, although it may have served such a purpose at one time. If
feasible you may want to consider running a new hot wire from the
breaker to the first outlet, leaving the green wire available for grounding.