On Dec 3, 11:16*am, (Doug Miller) wrote:
In article , stryped wrote:

If all main wires are removed (2 hots neutral, ground) and the green
bonding screw is removed, why am I getting continuity between the
neutral bus and ground bus?

Because you messed up somewhere. Without seeing it first-hand, it's hard to
say just where you messed up, but here are a few things to check:

- Have you confused the neutral and ground busses?

- Is there a jumper connecting the two busses?

- Is there a second bonding screw? I seem to recall from earlier discussions
that your panel has two neutral busses. If they're bonded together, and to the
box, and you removed only one bonding screw, well...

- Have you connected neutral and ground somewhere in your branch circuit
wiring? Remove *all* wires (the branch circuit neutrals) from the neutral bus,
and check again to see if there's continuity to the ground bus. If not, put
them back one at a time until there is continuity -- then you've found a
circuit with a problem. Don't assume that's the only such circuit.

- One way in which you can make an inadvertent connection between ground and
neutral is to overtighten the cable clamp on a Romex cable enough that it cuts
through the conductor insulation.

- Another way is through careless placement of ground wires in a receptacle
box (touching the neutral screws on the receptacle).

- Yet another way is by failing to understand that ground and neutral are
different things, and thus failing to understand that they need to be kept
separate when making fixture connections.

My detached garage has the two grounding busses. (The one this sub
panel will feed.).

There are only two items hooked to this sub panel and they dont have a
neutral. One to a 50 amp breaker for my upstairs 1 ton unit and one 20
amp breaker to my outside unit. (This is my small heat pump for a
bonus room), Black wire to breaker, white wire to breaker, and ground.
That is it.