Smallest "Listed" Ground Rod

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dronai

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The Smallest "Listed" Ground Rod driven electrode made of non ferrous is ______

250.52 (A) (5) (b) says 5/8"

but the answer to a practice test says "1/2" ???
 
dronai said:
The Smallest "Listed" Ground Rod driven electrode made of non ferrous is ______

250.52 (A) (5) (b) says 5/8"

but the answer to a practice test says "1/2" ???
Click to expand...

If you are on the 2008 cycle read 250.52(A)(5)(b) again paying particular attention to the last part of the sentence after the comma. The wording in the 2005 is slightly different but in essence means the same thing in the context of your question. I don't have the 2011.
 
eric9822 said:
If you are on the 2008 cycle read 250.52(A)(5)(b) again paying particular attention to the last part of the sentence after the comma. The wording in the 2005 is slightly different but in essence means the same thing in the context of your question. I don't have the 2011.
Click to expand...

That's a funky one!

The book says, 'stainless steel and copper or zinc coated steel', both of which are ferrous materials. If it was meant as three distinct and separate types, it should read, 'stainless steel, copper or zinc coated steel'.

To me, 'stainless steel and copper' is copper clad stainless. If the copper is not meant to be related to the stainless steel, then 'copper or zinc coated steel' would be the second option, stainless steel being the first. Either way, if read verbatim, strictly non ferrous materials are not allowed.
 
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K8MHZ said:
That's a funky one!

The book says, 'stainless steel and copper or zinc coated steel', both of which are ferrous materials. If it was meant as three distinct and separate types, it should read, 'stainless steel, copper or zinc coated steel'.

To me, 'stainless steel and copper' is copper clad stainless. If the copper is not meant to be related to the stainless steel, then 'copper or zinc coated steel' would be the second option, stainless steel being the first. Either way, if read verbatim, strictly non ferrous materials are not allowed.
Click to expand...

I agree, it's worded poorly. I think the wording in the 2005 is much more clear.
 
eric9822 said:
If you are on the 2008 cycle read 250.52(A)(5)(b) again paying particular attention to the last part of the sentence after the comma. The wording in the 2005 is slightly different but in essence means the same thing in the context of your question. I don't have the 2011.
Click to expand...


Ha !!! I see it !! Kind of a trick question should just say listed or 1/2" in the book.
 
For the OP, the question should ask what the smallest listed rod would be, and that is 1/2 inch. If it is 5/8 it doesn't have to be listed. I think that is the intent of the question, to illustrate the difference between a listed and non-listed requirement.

Throwing the 'non-ferrous' thing in just makes the question confusing and does nothing to teach the student, especially when it makes the student get tripped up on ambiguous sentences.

250.52(5) says that rod electrodes 'shall consist of the following materials'. (5)(b) states, as mentioned, 'stainless steel and copper or zinc coated steel'. That means, to be legal, the rod shall either be 'stainless steel and copper' or 'zinc coated steel'. Again, to stress, NO strictly non-ferrous rods are allowed if the NEC is followed closely.
 
eric9822 said:
I agree, it's worded poorly. I think the wording in the 2005 is much more clear.
Click to expand...

I see that the '08 had changed.

From the '05

(b) Electrodes of iron or steel shall be 5/8 in diameter. Stainless steel rods less than 5/8 in diameter, nonferrous rods, or their equivalent shall be listed and not less than 12 inch in diameter.

So, the words 'nonferrous rods' have been removed from the NEC as of the 08 cycle. To me, that means that CU only rods are no longer legal.
 
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