I put a demonstration together. [Linked Image]

The first two pictures show both methods.

[Linked Image]
[Linked Image]

Can anyone tell me why the 'green' screw is any better than the clamp screw?

Someone also asked Don why he takes the clamp out, well I do too and I think this picture illustrates why.

[Linked Image]

If there is going to be a short in a box with MC clamps it will be where the wires are pushing against the top of the extra clamp. Take that clamp out and there is much more room.

I had to use a wire nut on the box with the grounding pigtail as it is almost imposable to wrap the incoming ground wire around the screw due to the small space.

I consider myself a craftsman, I take pride in my job and I respect the code.

George's original post.

Quote
I maintain that the Contractor should be using the 8-32 hole provided for installing a GREEN screw and not use the cable clamp screw what-so-ever for grounding. I don't think he should even use the silver colored cable clamp screw in the hole provided for the GREEN ground screw. I need something official for a reference.

The answer is there is nothing in the NEC that prohibits what the contractor is doing as long as the clamp is removed from the screw.

It's that simple. [Linked Image]

JMO, Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts