GEC bonding jumpers NEC handbook error

Jpflex

Jpflex

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Electrician commercial and residential
If grounding electrodes are bonded together according to tge nec handbook picture then since a ground ring is included and is the largest size grounding electrode with the ring to be no smaller than 2 AWG NEC 250.52 (4) and 250.66 (B) shouldnt the minimum size main grounding electrode also be 2 AWG instead of a smaller 4 AWG shown?
 

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Since the service conductors are #3/0 a #4 GEC or bonding jumper to the ground ring is the minimum size required.
 
infinity said:
Since the service conductors are #3/0 a #4 GEC or bonding jumper to the ground ring is the minimum size required.
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No doubt you are correct but the wording of 250.66(C) can certainly lead one to believe it would need to be a #2 since that's the minimum size for the ring.
 
Ya, the way 250.66(C) is worded means (to me) that the conductor from the ground ring is not required to be larger than #2. It can still be smaller where 250.66 permits it to be. The ring itself, to qualify as an electrode, should not be smaller than #2.
 
infinity said:
Since the service conductors are #3/0 a #4 GEC or bonding jumper to the ground ring is the minimum size required.
Click to expand...
A #4 would normally be the GEC according to nec table 250.66 for 3/O ungrounded conductors

However since a ground ring is included in the grounding electrode system and the ground ring must not be less than 2 AWG, nec 250.52 A4 or less than the size permitted in 250.66 A through C per grounding electrode type

Then the main grounding electrode conductor GEC should be #2 but not the smaller #4 AWG shown in the NEC code book?
 
infinity said:
The ground ring needs to be a minimum of #2. According to T250.66 the GEC or bonding jumper can be as small as #8.
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Does not the main GEC have to be equal to or larger than the largest tap GEC bonding other grounding electrodes?
 
Jpflex said:
A #4 would normally be the GEC according to nec table 250.66 for 3/O ungrounded conductors
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Correct, so the GEC to a ground ring is not required in this case to be larger than #4.
Jpflex said:
Then the main grounding electrode conductor GEC should be #2 but not the smaller #4 AWG shown in the NEC code book?
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There is no such thing as a main GEC. It's either a GEC or a bonding jumper. Why would a GEC need to be #2 when T250.66 says #4 for #3/0?
Jpflex said:
However since a ground ring is included in the grounding electrode system and the ground ring must not be less than 2 AWG
Click to expand...
A ground ring electrode has minimum size of bare #2 copper. That does not mean that the GEC or bonding jumper connecting to the ground ring cannot be smaller.
 
Jpflex said:
A #4 would normally be the GEC according to nec table 250.66 for 3/O ungrounded conductors

However since a ground ring is included in the grounding electrode system and the ground ring must not be less than 2 AWG, nec 250.52 A4 or less than the size permitted in 250.66 A through C per grounding electrode type

Then the main grounding electrode conductor GEC should be #2 but not the smaller #4 AWG shown in the NEC code book?
Click to expand...
No 250.52(a)(4) is the size of the conductor required for the ground ring itself and has nothing to do with the sizing the gec/bonding jumper connected to the ring which is sized by t250.66 and if the table permits can be as small as #8 cu and 250.66(c) says the gec/bondjumper connected to the ring shall not be required to be larger than the conductor used for the ground ring, as long as it doesn’t extend to other electrodes that require a larger conductor it can be smaller if permitted by 250.66 , by doesn’t have to be larger. There is no error in the handbook
 
Ground-ring conductors must be sized to carry lightning-caused voltage gradients; the GEC need not.
 
Elect117 said:
Ya, the way 250.66(C) is worded means (to me) that the conductor from the ground ring is not required to be larger than #2. It can still be smaller where 250.66 permits it to be. The ring itself, to qualify as an electrode, should not be smaller than #2.
Click to expand...
The ground ring cannot be less than 2 AWG and if this is the case then the jumper for the
infinity said:
Correct, so the GEC to a ground ring is not required in this case to be larger than #4.

There is no such thing as a main GEC. It's either a GEC or a bonding jumper. Why would a GEC need to be #2 when T250.66 says #4 for #3/0?

A ground ring electrode has minimum size of bare #2 copper. That does not mean that the GEC or bonding jumper connecting to the ground ring cannot be smaller.
Click to expand...
I guess what i was confused on was nec 250.664 F:

...the grounding electrode conductor GEC shall be sized for the LARGEST grounding electrode conductor required among ALL the electrodes connected to it

I also thought i read somewhere in the code that the GEC or bonding jumper for the ground ring must be equal (not required larger) than the the ground ring wire size, but not smaller than 2 AWG

If the were the case, the GEC from the panel to (not considering water pipe) the ground ring would have to be a 2 AWG but not 4 AWG.

With this ground ring being the largest electrode/ EGC it would extend to all the smaller grounding electrodes/EGC

Above example is not pictured but what i was thinking as to why the GEC from the panel should have been 2 AWG but not 4 AWG

Perhaps i read something that wasnt there lol?
 
Jpflex said:
equal (not required larger)
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There are two different concepts. Equal would mean equal in all cases.

Not required larger than would mean that if the normal sizing process comes out smaller or equal, that's the answer. Whereas if the normal sizing process comes out larger, that's not actually required; you can use equal instead.

The language in 250.66(C) is not required larger.

Cheers, Wayne
 
The entire ground ring assembly itself is considered to be an electrode, not an electrode conductor or jumper.
 
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Jpflex said:
I also thought i read somewhere in the code that the GEC or bonding jumper for the ground ring must be equal (not required larger) than the the ground ring wire size, but not smaller than 2 AWG
Click to expand...
If you did read that then whomever wrote was wrong. You need to differentiate where the GEC begins. In the graphic posted no GEC or bonding jumper is required to be larger than #4.
 
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