517.14 Panelboard Bonding

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Ohms law

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Sioux Falls,SD
Can someone explain the intent of Article 517.14, how do you size the jumper? The article just states no smaller than 10awg.

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Not 250.102 (d)? Regardless, what is the intent?
The code usually references how to size everything but not this article.

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Ohms law said:
Not 250.102 (d)? Regardless, what is the intent?
The code usually references how to size everything but not this article.
Click to expand...
Just a guess, but I'd say the jumper is to mitigate any voltage gradient on the local grounding system resulting from voltage drop elsewhere on the system.

I don't know of any particular method of sizing the jumper other than not smaller than 10AWG copper.
 
Ok....scenario is hospital expansion that did not have this bonding design on the prints. But yet it is code.
Would not the grounding electrode conductor from a SDS that terminates at common ground bars in several locations be interconnected and cause no potential difference be the same?

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Ohms law said:
Ok....scenario is hospital expansion that did not have this bonding design on the prints. But yet it is code.
Would not the grounding electrode conductor from a SDS that terminates at common ground bars in several locations be interconnected and cause no potential difference be the same?

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Ideally the GES (electrodes and GECs) does not carry anything but fault current, especially for an SDS, so there is no reason for different points in the GES to be at different potentials.
If the primary neutral were used to establish a reference voltage for the secondary it would no longer be an SDS, and the voltage differences you refer to could be an issue if there is current on the neutral.
Fault current changes the whole thing.

mobile
 
GoldDigger said:
Ideally the GES (electrodes and GECs) does not carry anything but fault current, especially for an SDS, so there is no reason for different points in the GES to be at different potentials.
If the primary neutral were used to establish a reference voltage for the secondary it would no longer be an SDS, and the voltage differences you refer to could be an issue if there is current on the neutral.
Fault current changes the whole thing.

mobile
Click to expand...
I get what you are saying. So I would just run a 10awg between associated panels and call her a day.

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Ohms law said:
Can someone explain the intent of Article 517.14, how do you size the jumper? The article just states no smaller than 10awg.

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Click to expand...
It is simply for equipotential, use a #10 and your done. However, you still need to do the required testing as spelled out in NFPA99 6.3.3.............

Roger
 
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