2008NEC, Meaning of 200.2(B)

[dnem]

200.2(B) Continuity. . The continuity of a grounded conductor shall not depend on a connection to a metallic enclosure, raceway, or cable armour.

Stallcup?s Code Changes page 2-2, in the Author?s Comment blue lettering area, it says, ?A busbar or conductor must be used to make the connection between the neutral bar and the equipment ground bar, not the metal of the enclosure.?

Do you agree with that conclusion ?

The obvious conclusion is:
200.2(B), any panel that has neutrals on more than one bar can not depend the enclosure to bond them together. . As in neutral to neutral.

But does this also apply to the grounded conductor connection to grounding ? . And if you do agree with Stallcup, do you also agree with Stallcup?s use of the word ?equipment? ?

?A busbar or conductor must be used to make the connection between the neutral bar and the equipment ground bar, not the metal of the enclosure.?

Doesn?t the grounded wire get its ground path from the electrode conductor ? . How does the equipment ground effect the function of the grounded conductor ?

David

 

[George Stolz]

I agree with you, David, I'd say Stallcup's doesn't have it right. Looks to me as though this section makes no comment regarding the bonding jumper in service equipment, IMO.

I don't really see a prohibition in 250.28, 250.24, or 250.8 either.

 

[infinity]

I agree that the requirement is for the neutral current to not flow between two points on the metal of the panel. Seems like Stallcup's in error.

 

[dnem]

I don't really see a prohibition in 250.28, 250.24, or 250.8 either.

Not for equipment ground, I agree. . But how about electrode, 250.24(A)(4) ?

The bar where the electrode wire is terminated must be connected to the bar where the grounded wire is terminated by "wire or busbar", right ?

 

[George Stolz]

But how about electrode, 250.24(A)(4) ?

Well, that's different that what your original post was discussing.

200.2(B) Continuity. . The continuity of a grounded conductor shall not depend on a connection to a metallic enclosure, raceway, or cable armour.

There are not two items mentioned, just one, so the continuity of that one conductor can't depend on an enclosure.

The bar where the electrode wire is terminated must be connected to the bar where the grounded wire is terminated by "wire or busbar", right ?

Right, 250.24 is specific about where to land things under certain conditions, but I'm not seeing the connection to your original topic.

 

[dbnj49]

I took an exam prep course this summer and the book that wew worked out of was Stallcup's Design Book. There were alot of errors in the book. If you even check a Barnes and noble review of the book engineers say the say the same thing. My experience with the book tells me it will just confuse you more.