Ignoramus13229 wrote:
I installed a subpanel yesterday (see thread "Installed a subpanel!")
and am now having concerns. I attached EMT conduit to the panel and
subpanel using proper fittings. But the panel and subpanel are painted
with some sort of a grey paint. Does that paint conduct electricity? I
rely on my conduit to be the ground and, obviously, it needs to have
an excellent electrical bonding to the panel and subpanel.

The subpanel is on a 60A breaker.

My common sense suggests that the panel paint is probably conductive
and that since everything else is attached in the same way as my new
conduit, I should not worry. And yet, I would like a clarification.

Thanks.

i
Don't depend on the panel's paint to be conductive because that is not
likely to be the case. Take the tip of a large screw driver and scrape
away some of the paint before you tighten the locknut. Just back off
the locknut to the end of the threads and scape away the paint around
the knock out, then tighten the locknut. Put the tip of the screw
driver on one of the teeth of the locknut for the connector. Smack the
back end of the screw driver a good rap with the side of your lineman's
pliers or any similar tool. This will drive the locknut down tight and
cause it to bite through any remaining paint on the panel cabinet.

If you really want to make it bomb proof you can buy two bonding
bushings and apply one to the connector threads at either end of the
conduit run. The bonding bushings are fitted with a terminal lug for a
bonding wire that goes to the bonded buss bar in each of those cabinets.
In the sub panel's cabinet that should be the Equipment Grounding
Conductor (EGC) buss bar. In the service equipment cabinet it would be
the neutral buss bar. The use of bonding bushings is only required for
service raceways and raceways enclosing conductors with a voltage of
over 250 volts to ground. Best practice would be to pull a copper EGC
with the circuit conductors in the EMT and terminate it at the bonded
buss bar in each panel's cabinet.
--
Tom H