250.97 Exception?

[The Iceman]

I was reviewing the Mike Holt's Grounding versus Bonding DVD and I came up with a question about 250.97 exception. I know what an oversized and concentric knockout is, but what is an eccentric knockout?

 

[iwire]

I know what an oversized and concentric knockout is, but what is an eccentric knockout?

Concentric KOs are pretty much gone, they had equal size twist outs for each size that come out like a ring.

Eccentric KOs look similar to concentrics but each twist out looks like a 'C'.

With eccentrics the locknut of any size you use still hits the enclosure itself and not the just the twist outs.

 

[The Iceman]

Great! Thanks for the information. Maybe tomorrow I'll have something a little harder.

 

[infinity]

There are also tangential KO's. You'll see these mostly on Square D equipment. They're kind of a hybrid made from concentric and eccentric KO's put together.

 

[The Iceman]

There are also tangential KO's. You'll see these mostly on Square D equipment. They're kind of a hybrid made from concentric and eccentric KO's put together.

Your killing me. I'll have to check them out. Any other kinds of knockouts?

 

[mdshunk]

Your killing me. I'll have to check them out. Any other kinds of knockouts?

Sure, there area few more:

 

[Pierre C Belarge]

This is an eccentric KO