On Oct 14, 9:46*pm, Rick-Meister wrote:
You cannot use the conduit as the grounding conductor. Not anymore, at
least. Latest code says use a separate grounding conductor and bond it
to box.



On Tue, 14 Oct 2008 14:59:41 -0700 (PDT), wrote:
I'm using rigid steel conduit with steel boxes where I have elected to
use the conduit as the grounding conductor. * I have a 1/2" conduit
going into a masonry box with concentric 1/2 & 3/4 knockouts. *I'm not
crazy about concentric KO's so I thought I'd knock out to 3/4 and use
a 3/4 to 1/2 reducing bushing where the conduit enters the box. *(In
this case it would actually be an "expanding" bushing.) ... and a
locking nut on both sides of the
connection.

Isn't what I propose better than using the 1/2 knockout then praying
that the 3/4 knockout doesn't come loose? *-- better for insuring a
good ground? * The code does not say much about reducing bushings. * I
really rather not run a separate grounding conductor.

--zeb- Hide quoted text -

- Show quoted text -

Yes that also would be my understanding for any 'new' work; to current
codes.
Existing conduit previously used as grounding 'might' be grandfathered
although some jurisdictions inspections may reject it if other work is
being done in same area.