Are people using #12 grounding pigtails when you pull #10's (on a 20A breaker)?

[realolman]

Finite 10, this is beginning to seem like argument just to argue.

1. Surely you won't argue that #12 is insufficient for a 20A circuit.

2. I'm sure I will be corrected if I am wrong about this, but I think the only NEC requirement for VD is that it be held to 3 % in the branch circuit and 5% overall ....and I believe that is only in the FPN which is informational only.

3. It is not electrically necessary to increase the size of the conductors the entire length of the circuit to limit the voltage drop.

4. If it were necessary to increase the size of the entire length of the circuit conductors to 6 or 4 , as you seem to be saying, how would you connect them to a 20A. receptacle? ( or maybe two in a 2 gang box ) I don't think I would know how.

 

[George Stolz]

I think people are missing the fact that we are splicing 12 back in to the circuit conductors at the end of the run.

 

[Dennis Alwon]

Code requires the egc to be increased proportionately to the increase in ungrounded conductors. Thus where you increased the conductor then the egc must be increased. Where you tap to go to a recep. or the panel then you can size down with all the conductors as long as it is not smaller than what the OCPD allows.

 

[mcb1975]

Think about it this way. If you had a post light at the end of your drive way that was 1000ft from you panel box and you ran #8 wire for the VD, would you rewire the light fixture with a #8 ecg? As the ungrounded conductors change size so can the ecg.

 

[Finite10]

Code requires the egc to be increased proportionately to the increase in ungrounded conductors. Thus where you increased the conductor then the egc must be increased. Where you tap to go to a recep. or the panel then you can size down with all the conductors as long as it is not smaller than what the OCPD allows.

Where does the NEC say that though?

 

[jumper]

Where does the NEC say that though?

Where is it disallowed? Permissive code.

 

[Little Bill]

Where does the NEC say that though?

I'll repeat what has already been stated. NEC doesn't mandate for voltage drop, just FPN/Informational note giving reasons you might consider VD.

With that being said, if you do increase the ungrounded/grounded conductors for any reason, then you must also increase the EGC. You have that right.

What you seem to be not hearing/reading or ignoring is if you decrease the ungrounded/grounded conductors back down within range of the OCPD, then you can also decrease the EGC. Thus your EGC is the same size as the other conductors. Again, as long as they are the right size for the circuit protection.
That's about as clear as I know how to make it.

 

[jumper]

I'll repeat what has already been stated. NEC doesn't mandate for voltage drop, just FPN/Informational note giving reasons you might consider VD.

With that being said, if you do increase the ungrounded/grounded conductors for any reason, then you must also increase the EGC. You have that right.

What you seem to be not hearing/reading or ignoring is if you decrease the ungrounded/grounded conductors back down within range of the OCPD, then you can also decrease the EGC. Thus your EGC is the same size as the other conductors. Again, as long as they are the right size for the circuit protection.
That's about as clear as I know how to make it.

Nice job.:thumbsup:

 

[hurk27]

2008 NEC 250.122(B) reads;
Increased in Size.
Where ungrounded conductors are increased in size, equipment grounding conductors, where installed, shall be increased in size proportionately according to CM area of the ungrounded conductors.

Many miss the comprehension of simple English when reading a sentence, this is a common mistake.

The word "where" as used in this sentence is used as a noun (place), and can be compared to other sentences very similar as it is written in the code:

"Where you sleep, noise is prohibited"
"Where you park your car, it might get hit by the snow plow"
"Where you install more then three conductors in a raceway, you must derate"
in each of the above sentences the word "Where" is used as meaning a place, and this is how this section is interpreted.

the NEC is a permissive document as many laws are, as such it must spell out what you cant do, not what you can.

It is very common to run large gage wire to a string of light pole as in Bob's example, and as you get passed loads the wire sized can be reduced since the load is less, as long as it is not reduced below the rating of the breaker.
At each step in size of the wire so can the EGC size also be reduced, otherwise you end up running the large wire size the whole circuit, you will not win many bids doing this against others who know the meaning of the word "Where"

 

[augie47]

Many miss the comprehension of simple English when reading a sentence, this is a common mistake.

The word "where" as used in this sentence is used as a noun (place), and can be compared to other sentences very similar as it is written in the code:

"Where you sleep, noise is prohibited"
"Where you park your car, it might get hit by the snow plow"
"Where you install more then three conductors in a raceway, you must derate"
in each of the above sentences the word "Where" is used as meaning a place, and this is how this section is interpreted.

the NEC is a permissive document as many laws are, as such it must spell out what you cant do, not what you can.

It is very common to run large gage wire to a string of light pole as in Bob's example, and as you get passed loads the wire sized can be reduced since the load is less, as long as it is not reduced below the rating of the breaker.
At each step in size of the wire so can the EGC size also be reduced, otherwise you end up running the large wire size the whole circuit, you will not win many bids doing this against others who know the meaning of the word "Where"

WHERE did you come up with that (joking) Good point !

 

[suemarkp]

For the original question, is he asking about the green pigtail to the receptacle, or a pigtail to a metal box? I can see the reasoning for allowing #12 on the receptacle, since those probably have pigtails that are back to #12. But doesn't the box bonding pigtail require a #10 if any EGC in the box is a #10?

 

[hillbilly1]

For the original question, is he asking about the green pigtail to the receptacle, or a pigtail to a metal box? I can see the reasoning for allowing #12 on the receptacle, since those probably have pigtails that are back to #12. But doesn't the box bonding pigtail require a #10 if any EGC in the box is a #10?

If the largest ocp is 20 amps, it does not. If that or another circuit in the box has an ocp higher than 20 amp, then the jumper must be sized accordingly.

 

[kwired]

For the original question, is he asking about the green pigtail to the receptacle, or a pigtail to a metal box? I can see the reasoning for allowing #12 on the receptacle, since those probably have pigtails that are back to #12. But doesn't the box bonding pigtail require a #10 if any EGC in the box is a #10?

That is my take on it. Now if the circuit conductors to the receptacle are 10 AWG then so should be the EGC. The box need bonded by an equivelant largest conductor entering the box.

 

[Dennis Alwon]

Another example to this old thread. If I run number 12 wire 50' from a panel to a jb then continue another 150' with #10 do I need the egc to be #10 all the way back to the panel even though I have #12 originating from that point. The egc never needs to be larger than the circuit conductors--250.122.

Now reverse this setup-- it is no different.

 

[jmellc]

Anybody have a citation that allows a reduction after table 250.122? I sure am open to learn of one. Seems explicitly stated to me.

The mudring, the green screw on a receptacle, or a lightpole - all are the end of the line for the EGC system. From ground bar to anywhere the user may encounter exposed non-current carrying metallic parts ? no reduction in CM allowed, as written in 250.122(B), for any reason I can read.

Here's what I'm reading:

2008 NEC
"250.122(B);
Increased in Size.
Where ungrounded conductors are increased in size, equipment grounding conductors, where installed, shall be increased in size proportionately according to the circular mil area of the ungrounded conductors."

I have worked a lot of jobs where we pulled oversized wire for the main runs, then down to #12 for side pulls, i e, home runs in 10 to all main j boxes, then #12 from there on. Perfectly legal to use #12 pigtails with the #12 grounds.

Suppose you run out of #12 white for a short run and use #10 instead, still using a 12 hot. IMHO, a 12 ground is good here too. If I pulled neutral and hot in 10, I should use a 10 ground also.

 

[don_resqcapt19]

From the NEC Style Manual.

where (location or situation)

 

[Strathead]

I'll repeat what has already been stated. NEC doesn't mandate for voltage drop, just FPN/Informational note giving reasons you might consider VD.

With that being said, if you do increase the ungrounded/grounded conductors for any reason, then you must also increase the EGC. You have that right.

What you seem to be not hearing/reading or ignoring is if you decrease the ungrounded/grounded conductors back down within range of the OCPD, then you can also decrease the EGC. Thus your EGC is the same size as the other conductors. Again, as long as they are the right size for the circuit protection.
That's about as clear as I know how to make it.

Just to throw a monkey wrench in the works, in Florida, the Building code does require a maximum VD of 3% branch circuit 5% overall. So what! The remainder of your argument is still true. If you are so close to the maximum voltage drop, that 13 amps on an 8" piece of wire will put you over, then oops!

In case I didn't make this perfectly clear. I fully agree with Little Bill!

 

[Finite10]

For the original question, is he asking about the green pigtail to the receptacle, or a pigtail to a metal box? I can see the reasoning for allowing #12 on the receptacle, since those probably have pigtails that are back to #12. But doesn't the box bonding pigtail require a #10 if any EGC in the box is a #10?

Closest to what I'm saying.

Let me ask where the black portions of the code allow for reduction, or refers to breaker size here:

250.122(B);
Increased in Size.
Where ungrounded conductors are increased in size, equipment grounding conductors, where installed, shall be increased in size proportionately according to the circular mil area of the ungrounded conductors.

Where does it allow reducing from #10 to #12 at any point in the grounding path? It does not.

Again, please provide the citation or exception and I'm all in. Contractors do this in my area. Those that do not may get a correction and have to replace the #12 prefab pigtails with #10.

 

[Little Bill]

Closest to what I'm saying.

Let me ask where the black portions of the code allow for reduction, or refers to breaker size here:

250.122(B);
Increased in Size.
Where ungrounded conductors are increased in size, equipment grounding conductors, where installed, shall be increased in size proportionately according to the circular mil area of the ungrounded conductors.

Where does it allow reducing from #10 to #12 at any point in the grounding path? It does not.

Again, please provide the citation or exception and I'm all in. Contractors do this in my area. Those that do not may get a correction and have to replace the #12 prefab pigtails with #10.

Again, you are missing the word "where". It doesn't say you have to increase the ungrounded conductors. But, if you do increase them, then the EGC has to be increased also. And again if you choose to reduce the ungrounded conductors to match the OCPD, then you can also reduce the EGC to the same size as the ungrounded. The whole point of the rule is to keep the EGC the same as the ungrounded for potential fault current.
You should know how hard it would be to connect #10s to a receptacle or switch, so if your conductors were increased for VD then you can reduce them at the box for ease termination.
To your specific question," where does it allow reducing the EGC from 10 to 12 at any point in the grounding path?" worded just like that it would not, but if you also reduce the ungrounded you may also reduce the EGC, and again if the reduction was not lower than what is needed for the protection of the circuit.

If you still want to keep your #10, you are free to do so, and also free to fuss when trying to terminate them on a 15 or 20A device.

 

[iwire]

Where does it allow reducing from #10 to #12 at any point in the grounding path? It does not.

Again, please provide the citation or exception and I'm all in. Contractors do this in my area. Those that do not may get a correction and have to replace the #12 prefab pigtails with #10.

This is the second time posting this, care to comment on it this time?

250.122 Size of Equipment Grounding Conductors.
(A) General. Copper, aluminum, or copper-clad aluminum
equipment grounding conductors of the wire type shall not
be smaller than shown in Table 250.122, but in no case shall
they be required to be larger than the circuit conductors supplying
the equipment. Where a cable tray, a raceway, or a
cable armor or sheath is used as the equipment grounding
conductor, as provided in 250.118 and 250.134(A), it shall
comply with 250.4(A)(5) or (B)(4).

Equipment grounding conductors shall be permitted to
be sectioned within a multiconductor cable, provided the
combined circular mil area complies with Table 250.122.

If I reduce the circuit condutor size I can reduce the EGC size.