Size of GEC for ground rod

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Table 250.66 shows the minimum size of GEC, but, what if the service entrance conductors is sized lower than #8 AWG, would i still used the minimum #8 AWG for GEC?

how about the grounded service conductor? 250.24 (C) (1) says that the grounded service conductor shall not be smaller than the required electrode conductor specified in table 250.66 but shall not be required to be larger than the largest ungrounded service entrance phase conductor.
 
enteng14 said:
Again sir,

If the rating of the service equipment is 15 amperes and the grounding electrode use is ONLY the ground rod and the size of ungrounded service entrance (hot) conductors is # 12 AWG (3.5 sq. mm). What would be the size of the GEC and the grounded service conductor considering that 250.66(A) only refer to the maximum size of GEC for ground rod electrode?
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Let me make this simple.

First: Why would your grounded service conductor need to be larger than your ungrounded service conductor here?

Second: Table 250.66

Top Line:
Size of largest ungrounded Copper, "2 or smaller"
Size of GEC Copper, #8

250.66 (A) ...that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire...

The minimum you need is #8. And you don't have to go over #6.
 
I like simple terms that I can grasp. Try this.

I like simple terms that I can grasp. Try this.

enteng14 said:
how about the grounded service conductor? 250.24 (C) (1) says that the grounded service conductor shall not be smaller than the required electrode conductor specified in table 250.66 but shall not be required to be larger than the largest ungrounded service entrance phase conductor.
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Exactly! :D Your eyes do not deceive you.

If you install a grounded service conductor make sure it's never, ever, smaller than the GEC for you system, but, it does not need to be larger than you ungrounded service entrance phase conductor.
 
Excuse my ignorance please, but why does anyone state anything over 6awg. isn't permitted? I never got that.

Not a construction guy, excuse my greeness:cool:
 
enteng14 said:
Again sir,

If the rating of the service equipment is 15 amperes and the grounding electrode use is ONLY the ground rod and the size of ungrounded service entrance (hot) conductors is # 12 AWG (3.5 sq. mm). What would be the size of the GEC and the grounded service conductor considering that 250.66(A) only refer to the maximum size of GEC for ground rod electrode?
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Again sir, in no case will the GEC be smaller then 8 AWG per table 250.66, once the service size increases to the point that GEC would be larger then 6 AWG then 250.66(A) kicks in.
 
enteng14 said:
Table 250.66 is not applicable for GEC sizing for ground rod electrode. NEC 250.66 (A) discusses only that GEC isn't required to be larger than 6 AWG.
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My first answer in post #3 was correct. 250.66 does apply.
 
76nemo said:
Excuse my ignorance please, but why does anyone state anything over 6awg. isn't permitted? I never got that.

Not a construction guy, excuse my greeness:cool:
Click to expand...


It is permitted it just isn't required. Assuming you are talking about a GEC to a rod.
 
76nemo said:
Excuse my ignorance please, but why does anyone state anything over 6awg. isn't permitted? I never got that.

Not a construction guy, excuse my greeness:cool:
Click to expand...
you can run a larger size GEC if you want. the code just says you can run a #6 to the ground rod and be done with it. same with the ufer ground, you can run a #4 and be done with it. There is also nothing wrong with sizing the GEC to 250.66 if you choose but your not required too. if you use building steel as the electrode then you need to size it to 250.66. same with using the water pipe as an electrode.
 
frizbeedog said:
Let me make this simple.

First: Why would your grounded service conductor need to be larger than your ungrounded service conductor here?

Second: Table 250.66

Top Line:
Size of largest ungrounded Copper, "2 or smaller"
Size of GEC Copper, #8

250.66 (A) ...that portion of the conductor that is the sole connection to the grounding electrode shall not be required to be larger than 6 AWG copper wire...

The minimum you need is #8. And you don't have to go over #6.
Click to expand...

First: I don't need my grounded service conductor need to be larger than ungrounded service conductor. that's why i'm asking for the size of grounded service conductor and grounding electrode conductor for 15-ampere service equipment where the ungrounded service conductor size #12 AWG (3.5 sq mm).

Second: If the minimum for GEC is #8 AWG, then this is the special case that:

1. the GEC and grounded service conductor is larger than the ungrounded service entrance conductor sizing smaller than #8 AWG.

or

2. grounding electrode conductor will be larger than the grounded service conductor and ungrounded service conductor for size #8 AWG below.
 
frizbeedog said:
Exactly! :D Your eyes do not deceive you.

If you install a grounded service conductor make sure it's never, ever, smaller than the GEC for you system, but, it does not need to be larger than you ungrounded service entrance phase conductor.
Click to expand...


Is this applicable for ungrounded service conductor size below #8 AWG considering than the minimum for grounding electrode conductor as per table 250.66 is #8 AWG???
 
enteng14 said:
that's why i'm asking for the size of grounded service conductor and grounding electrode conductor for 15-ampere service equipment where the ungrounded service conductor size #12 AWG (3.5 sq mm).
Click to expand...

Check out 230.23(B) and 230.31(B).
 
76nemo said:
Excuse my ignorance please, but why does anyone state anything over 6awg. isn't permitted? I never got that.

Not a construction guy, excuse my greeness:cool:
Click to expand...


For Ground rod electrode (ground rod was used solely as grounding electrode) the size stated is #6 AWG because beyond #6 AWG would be useless. The size of the ground rod is smaller than GEC beyond #6..
 
iwire said:
I don't know.

230.23(B) and 230.31(B)
Exception: Conductors supplying only limited loads of a single branch circuit -shall not be smaller than #12 AWG.


That has nothing to do with conductor sizes.
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230.79(A) One circuit installation
For installations to supply only limited loads of a single branch circuit, the service disconnecting means shall have a rating of not less than 15 amperes.

also from NEC2005 Handbook under 230.79
Smaller sizes are permitted down to 14AWG copper for installations with one circuit. (service conductors)
 
enteng14 said:
230.79(A) One circuit installation
For installations to supply only limited loads of a single branch circuit, the service disconnecting means shall have a rating of not less than 15 amperes.

also from NEC2005 Handbook under 230.79
Smaller sizes are permitted down to 14AWG copper for installations with one circuit. (service conductors)
Click to expand...

Lets stop dinkin around here. :mad:

Get to the point and clarify your installation. Is this a service served by the serving utilty or is this a private installation?

Lets not mix apples and oranges.
 
frizbeedog said:
Lets stop dinkin around here. :mad:

Get to the point and clarify your installation. Is this a service served by the serving utilty or is this a private installation?

Lets not mix apples and oranges.
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this is to be supplied by a distribution utility. the customer's service equipment is 15 amperes with #10AWG conductors. I'm trying to configure the size of the grounded service conductors and the grounding electrode conductor.:confused:
 
enteng14 said:
this is to be supplied by a distribution utility. the customer's service equipment is 15 amperes with #10AWG conductors. I'm trying to configure the size of the grounded service conductors and the grounding electrode conductor.:confused:
Click to expand...

grounded = #10

GEC =#8
 
enteng14 said:
this is to be supplied by a distribution utility. the customer's service equipment is 15 amperes with #10AWG conductors. I'm trying to configure the size of the grounded service conductors and the grounding electrode conductor.:confused:
Click to expand...

Ok now I can help you. :)

230.79 (A) and (B) refer to the number of branch circuits to be supplied, and the rating of the required disconnect. Thats it. Only the disconnect.

Now read (D).

Go back and read 250.24 (C) (1) Keeping in mind that the grounded service conductor is not required to be larger....yada, yada. It did not say it can't be.

Install the size disconnect you need and do as iwire said about 230.23 (B) and 230.30 (B) with regards to the service conductor size.

Then install a #8 to your ground rod and have a nice day.
 
frizbeedog said:
Ok now I can help you. :)

230.79 (A) and (B) refer to the number of branch circuits to be supplied, and the rating of the required disconnect. Thats it. Only the disconnect.
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Are'nt 230.79 discusses about rating service disconnect here?

NEC2005 Handbook 230.79 explained that smaller sizes are permitted down to 14AWG for installations with one circuit.
Let's say you have a roadway lighting that is only a single circuit (the same service equipment protect the electrical installation- no branch circuit). The ungrounded service entrance is size #10 AWG with service equipment of 15 amperes and using only ground rod as grounding electrode.


Go back and read 250.24 (C) (1) Keeping in mind that the grounded service conductor is not required to be larger....yada, yada. It did not say it can't be.

Install the size disconnect you need and do as iwire said about 230.23 (B) and 230.30 (B) with regards to the service conductor size.
Click to expand...

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.
 
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