GEC entering panel

[tom baker]

I just did a grounding class, one of the students saw a demo of a panel with and without a kenny clamp, in a simulated lightning strike, the one without had a big hole blown in the back of it.
I need to track down more info on the demo.

 

[don_resqcapt19]

Tom,

I need to track down more info on the demo.

And who paid for it.
Don

 

[celtic]

...and as compared to a romex connector

 

[RayS]

The device referred to inthe last post is called a "Kenny Clamp". An inspector in this area "invented" the clamp and had it patented. By what I consider as a "creative interpretation" of the NEC he determined that such a device is required. As far as I know, the jurisdiction in which he works is the only jurisdicition requiring such a device. Since this device secures the grounding conductor to the panel, I question the need to continue the conductor to the ground/neutral bar, but the "inventor" insists that it is still needed. I haven't heard of any housings burning down or persons being electrocuted because the grounding conductor was routed through on of the small knocouts in the panel or brought through a 1/2 inch knockout using a bushing or romex connector.

I believe that "creative interpretation" is just plain wrong.

250.64 (E) Enclosures for Grounding Electrode Conductors
"... shall be electrically continuous from the point of attachment to cabinets
or equipment to the grounding electrode..."

this obviously cannot refer to the actual cabinet attatched to, and if it did, we would need some really long and really flexible panels to stretch all the way to the grounding electrode...

Looks like a decent product, and I'd consider using it if they didn't imply that all the installs I've done were wrong...

 

[Bob NH]

I just did a grounding class, one of the students saw a demo of a panel with and without a kenny clamp, in a simulated lightning strike, the one without had a big hole blown in the back of it.
I need to track down more info on the demo.

The bonding screw in most panels is designed to bond the enclosure. It is a pretty poor connection. If a test is set up to put the "simulated lightning strike" through that screw, and another through a Kenny clamp, then it would not be surprising that the bond screw connection would cause a hole in the enclosure while the Kenny clamp connection would not.

HOWEVER, the current from a real lightning strike would be more likely to go to ground via the grounding electrode conductor connected to the neutral bus; not through the bonding screw.

That test sounds like the electrical test corrollary to the principle that "Figures don't lie, but liars can figure."

 

[George Stolz]

I fail to see how a bonding bushing would not do the exact same thing as the "Kenny Connector."

An inspector in this area "invented" the clamp and had it patented. By what I consider as a "creative interpretation" of the NEC he determined that such a device is required. As far as I know, the jurisdiction in which he works is the only jurisdicition requiring such a device.

The spirit of free enterprise in full effect!

 

[George Stolz]

I read Georges thread and IMO the inspector was wrong same here.

Thanks for the support. And, welcome to the forum!

Better still, y'all should click on George's "Carpentry Hack" link. Urph. What do you call that corner?!?

Hey, it's a barn, for Pete's sake! (I'm not quite done yet, either.)

The only insulated, heated tack room I own.

By the way, I still haven't gotten my check in the mail, be careful.