Size of GEC for ground rod

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wirebender said:
grounded = #10

GEC =#8


This was also my recommendation for the said installation but it hinders me to used this because of the code requirement that the grounded conductor shall not be less than the GEC..:confused:

again another special case...maybe another exception..
 
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enteng14 said:
That's what i'm trying to point, there are cases that the grounded service conductor and the grounding electrode conductor are larger than the ungrounded service conductor when the circuit you are serving one circuit or two circuit installations.

And the problem with that is......?

Welcome to the Matrix Neo. You should have taken the blue pill. :wink:
 
frizbeedog said:
And the problem with that is......?

Welcome to the Matrix Neo. You should have taken the blue pill. :wink:


:grin: the problem? i do not see any..:grin: hahaha.. now i can see the matrix morpheus..now i understand..

for the answer of my query for ungrounded service conductors size smaller #8 awg the minimum size of GEC is still #8 AWG of table 250.66 and the minimum size of the grounded service conductor is also #8 AWG as supported by 250.24(C)(1) that the grounded conductors shall not be smaller than GEC as specified in table 250.66.
:grin:

YES I"M NEO....:cool:
 
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enteng14 said:
:grin: the problem? i do not see any..:grin: hahaha.. now i can see the matrix morpheus..now i understand..

for the answer of my query for ungrounded service conductors size smaller #8 awg the minimum size of GEC is still #8 AWG of table 250.66 and the minimum size of the grounded service conductor is also #8 AWG as supported by 250.24(C)(1) that the grounded conductors shall not be smaller than GEC as specified in table 250.66.
:grin:

YES I"M NEO....:cool:

"Do you think that's air you're breathing.......?"

"I know kung fu"

Glad we could help. :)
 
enteng14 said:
code requirement that the grounded conductor shall not be less than the GEC..:confused:

250.24(C)(1) (1) Routing and Sizing This conductor shall be routed with
the phase conductors and shall not be smaller than the required grounding electrode conductor specified in Table 250.66 but shall not be required to be larger than the largest ungrounded service-entrance phase conductor.
 
frizbeedog said:
"Do you think that's air you're breathing.......?"

"I know kung fu"

Glad we could help. :)


Thanks frizbeedog for the enlightenment on the issue..:cool:

I'm just worried how to explain this to small residential customers wherein the ungrounded service conductor is smaller than the grounded service conductor for single phase, 230 volts, 3-wire line-to-line service (2-hot, 1 ground) and we have no line-ground loads. The used of grounded conductor was only for ground-fault and there is no current flowing during normal operation.
 
wirebender said:
250.24(C)(1) (1) Routing and Sizing This conductor shall be routed with
the phase conductors and shall not be smaller than the required grounding electrode conductor specified in Table 250.66 but shall not be required to be larger than the largest ungrounded service-entrance phase conductor.


as explained by frizbeedog: it states that grounded conductor shall not be required to be larger than the largest ungrounded service conductor but it doesn't said it can't be..
 
enteng14 said:
Thanks frizbeedog for the enlightenment on the issue..:cool:

I'm just worried how to explain this to small residential customers wherein the ungrounded service conductor is smaller than the grounded service conductor for single phase, 230 volts, 3-wire line-to-line service (2-hot, 1 ground) and we have no line-ground loads. The used of grounded conductor was only for ground-fault and there is no current flowing during normal operation.

Hand them a code book, then hand them the bill. :)

I beleive it is because of ground faults that this is why this is the way it is. One thing always leads to another. You really need to make sure any fault will clear.
 
frizbeedog said:
Hand them a code book, then hand them the bill. :)

I beleive it is because of ground faults that this is why this is the way it is. One thing always leads to another. You really need to make sure any fault will clear.

it is for ground fault but line to line fault is of greater magnitude than ground fault, then why use a larger size of grounded conductor? that is the question to me..:roll:
 
enteng14 said:
it is for ground fault but line to line fault is of greater magnitude than ground fault, then why use a larger size of grounded conductor? that is the question to me..:roll:

Line to line is a different breed of fault. That is not what you are dealing with when installing or sizing the grounded conductor. See 250.2 Definitions. You are trying to direct ground faults back to the supply source.

Low-impedance path

Let that be you mantra.
 
frizbeedog said:
Line to line is a different breed of fault. That is not what you are dealing with when installing or sizing the grounded conductor. See 250.2 Definitions. You are trying to direct ground faults back to the supply source.

Low-impedance path

Let that be you mantra.

Agree. But considering that the magnitude of line to line fault current is greater than that of the line to ground fault current, why require a larger size of conductor (say 8 mm2) if your ungrounded phase conductor is only 3.5 mm2 only? Isn't it that the ungrounded phase conductor will be subject to higher fault current such as line to line fault current than the grounded service conductor which will be subject to line to ground fault current only? THis is kind of inconsistent. Thanks.
 
enteng14 said:
This was also my recommendation for the said installation but it hinders me to used this because of the code requirement that the grounded conductor shall not be less than the GEC..:confused:

again another special case...maybe another exception..

Please cite the code section that says that the grounded conductor shall not be less than the GEC. I am missing it and am not aware that such a requirement exists. (That's a polite way of saying I think you are wrong.)

The code that applies is as follows:

The "but" in the first sentence of 250.24(C)(1) precedes an EXCEPTION to the previous clause in 250.24(C)(1) which says that the grounded conductor shall not be smaller than the GEC. Therefore, the requirements are that:
1. The GEC must meet the requirements of 250.66 AND
2. The ungrounded conductor must be (a) large enough for the load but in no case is it required to be larger than the ungrounded conductors, and (b) as large as the GEC per 250.66 BUT if the GEC is larger than the ungrounded conductors then the grounded concuctor need not be larger than the ungrounded conductors.
 
Bob NH said:
Please cite the code section that says that the grounded conductor shall not be less than the GEC. I am missing it and am not aware that such a requirement exists. (That's a polite way of saying I think you are wrong.)

The code that applies is as follows:

The "but" in the first sentence of 250.24(C)(1) precedes an EXCEPTION to the previous clause in 250.24(C)(1) which says that the grounded conductor shall not be smaller than the GEC. Therefore, the requirements are that:
1. The GEC must meet the requirements of 250.66 AND
2. The ungrounded conductor must be (a) large enough for the load but in no case is it required to be larger than the ungrounded conductors, and (b) as large as the GEC per 250.66 BUT if the GEC is larger than the ungrounded conductors then the grounded concuctor need not be larger than the ungrounded conductors.

I think sir you already mentioned the site where the grounded conductor should not be smaller than the GEC.

2. The ungrounded conductor must be (a) large enough for the load but in no case is it required to be larger than the ungrounded conductors, and (b) as large as the GEC per 250.66 BUT if the GEC is larger than the ungrounded conductors then the grounded concuctor need not be larger than the ungrounded conductors

now i'm confused about this.. I think you are referring to the grounded service conductor and not the ungrounded service conductor because you are comparing the same conductors (ungrounded conductor)..
 
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Enteng14,
I understand the fact that you want to get all the answers you need and feel good about it which is a a good thing. Why do you have to convince or educate your customers when it is not necessary. You must have a lot of time in your hand . Do not drive yourself crazy by trying to make sense out of everything in life, specially with NEC. I personally do not drive myself crazy, if I am in question of making a decision on a size of a conductor whether it should be 6 AGW or 4 AWG ( in general, not just with grounding topic ), i go with the bigger size and get over with. Adjust my price accordingly. I know some people may disagree with what I am saying but this is what I feel.
 
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