# ground wire size?



## Dennis Alwon (May 9, 2009)

If you upsize the ungrounded conductors then you must upsize the egc proportionately, otherwise no rule for distance. Look at 250.122(B)


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## HARRY304E (Sep 15, 2010)

Shawn23 said:


> I know 250.122 give a list of sizes. Is there a requirement based on "distance", like the ungrounded conductors? The distance is 300 feet.



If you increase the size of your ungrouned conductors then yes...


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## Shawn23 (Jan 5, 2011)

Dennis Alwon said:


> If you upsize the ungrounded conductors then you must upsize the egc proportionately, otherwise no rule for distance. Look at 250.122(B)


 
Thanks for the help. I dont usually run into anything over 50ft so this is my 1st time useing this code.


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## Dennis Alwon (May 9, 2009)

Shawn23 said:


> Thanks for the help. I dont usually run into anything over 50ft so this is my 1st time useing this code.


You're welcome. If you need help calculating the upsize I am sure guru harry can help or perhaps someone else.


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## Shawn23 (Jan 5, 2011)

Dennis Alwon said:


> You're welcome. If you need help calculating the upsize I am sure guru harry can help or perhaps someone else.


 
I have already figured the voltage drop and wire size for the pumps ungrounded conductors which have a .0507 cir. mil. area.

Now reading 250.122 B i could use some help with how to get the equipment ground size.


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## Dennis Alwon (May 9, 2009)

Shawn23 said:


> I have already figured the voltage drop and wire size for the pumps ungrounded conductors which have a .0507 cir. mil. area.
> 
> Now reading 250.122 B i could use some help with how to get the equipment ground size.


What size conductor would you have used if there was no voltage drop involved? What size did you decided to use Take their cir. mil and determine how much larger the upsized ungrounded conductor is from the original conductor. 

Now determine the original egc and upsize by the same amount.

Thus if the ungrounded conductor was up sized 2.5 times the original, then the egc must be 2.5 times larger also.

Note for sizes 14, 12 and 10 the upsize of the ungrounded would be the same for the egc since for those size branch circuits the egc is a 1 to 1 ratio.


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## dronai (Apr 11, 2011)

Dennis, you also, are a code "Guru"


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## Rockyd (Apr 22, 2007)

250.122(B)

Here you go-

*(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. 
The general requirement for selecting the minimum size equipment grounding conductor is to select directly from *Table 250.122* based on the rating or setting of the feeder or branch-circuit overcurrent protective device(s). Where the ungrounded circuit conductors are increased in size to compensate for voltage drop or for any other reason related to proper circuit operation, *250.122(B)* requires that the equipment grounding conductors be increased proportionately. Increases in ungrounded circuit conductor size for the purposes of ampacity adjustment, correction, or both are not required to be considered in applying the provisions of *250.122(B)*. In some cases, use of a conductor with a higher insulation temperature rating allows for compliance with ampacity adjustment and correction requirements without having to increase the circular mil area of the conductor. 

*Calculation Example *​ 
A 240-volt, single-phase, 250-ampere load is supplied from a 300-ampere breaker located in a panelboard 500 ft away. The conductors are 250-kcmil copper, installed in rigid nonmetallic conduit, with a 4 AWG copper equipment grounding conductor. If the conductors are increased to 350 kcmil, what is the minimum size for the equipment grounding conductor based on the proportional-increase requirement? 
*Solution *
Step 1. Calculate the size ratio of the new conductors to the existing conductors: 

350,000 cm........ 
250,000cm = 1.4​ 


Step 2. Calculate the cross-sectional area of the new equipment grounding conductor: 

The 1.4 becomes your multiplier.


41,740cm x 1.4 = 58,436cm

According to Chapter *9*, *Table 8*, 4 AWG, the size of the existing grounding conductor, has a cross-sectional area of 41,740 circular mils. 
Step 3. Determine the size of the new equipment grounding conductor. Again, referring to Chapter *9*, *Table 8*, we find that 58,436 circular mils is larger than 3 AWG. The next larger size is 66,360 circular mils, which converts to a 2 AWG copper equipment grounding conductor.

This should help...


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## Dennis Alwon (May 9, 2009)

dronai said:


> Dennis, you also, are a code "Guru"


I am trying to take the title from Harry (aka Leo) but "everyone knew him as Nancy"--Beatles.


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## Rockyd (Apr 22, 2007)

Dennis Alwon said:


> I am trying to take the title from Harry (aka Leo) but "everyone knew him as Nancy"--Beatles.


Thanks for all the respect:no::whistling2::whistling2:


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## dronai (Apr 11, 2011)

Rockyd said:


> Thanks for all the respect:no::whistling2::whistling2:


 
You were one of the few, that solved the resisters in parallel problem RESPECT :thumbsup:

That earned big Guru points !


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## Rockyd (Apr 22, 2007)

dronai said:


> You were one of the few, that solved the resisters in parallel problem RESPECT :thumbsup:
> 
> That earned big Guru points !


 
One of the hard parts about formulation...

After you run the numbers, does it jive with reality ( go to common sense zone, does it seem right)? Hate to have a loud "BOOM", and say who was the moron who figured that part out:blink::whistling2:

"I thought the engineer checked that....":001_huh:


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## dronai (Apr 11, 2011)

Rockyd said:


> One of the hard parts about formulation...
> 
> After you run the numbers, does it jive with reality ( got to common sense zone, does it seem right)? Hate to have a loud "BOOM", and say who was the moron who figured that part out:blink::whistling2:
> 
> "I thought the engineer checked that....":001_huh:


 
Most of the Commercial jobs, I've worked on, were all engineered, with a PE stamp on them. No thinking required, just "pipetrician" work, and wire pulling.


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## Rockyd (Apr 22, 2007)

dronai said:


> Most of the Commercial jobs, I've worked on, were all engineered, with a PE stamp on them. No thinking required, just "pipetrician" work, and wire pulling.


Most the time our jobs are too. But if I'm sitting in an office, and see anything on the print, that seems "strange", will go do the math, $ change order $ time! Got to get the money out of a turnip (GC) somehow! I do know how to get blood out of a turnip!:laughing:


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## dronai (Apr 11, 2011)

Rockyd said:


> Most the time our jobs are too. But if I'm sitting in an office, and see anything on the print, that seems "strange", will go do the math, $ change order $ time! Got to get the money out of a turnip (GC) somehow! I do know how to get blood out of a turnip!:laughing:


 
How long were you on those high rises, in Vegas ? That last new cluster that just went in is massive ! Looks like 3 buildings joined. This one I think, The City Center.

http://www.citycenter.com/


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## Rockyd (Apr 22, 2007)

dronai said:


> How long were you on those high rises, in Vegas ? That last new cluster that just went in is massive ! Looks like 3 buildings joined. This one I think, The City Center.http://www.citycenter.com/


One and off for about five or six years. Was getting kind of serious about the place (was there long enough to work deck in the heat!) but not out of 357. So when the bust arrived, I was working at Fontainebleau. On Friday, they laid off 50 guys, we thought they were maybe just weeding out the "deadwood". On Monday, 300 of us got the word at coffee time that we would be "waiting" to see if we were going back to work. Around 10:30 am, our foreman brought us checks for Monday, and Tuesday (Thanks Conti, decent electrical contractor) said it was "all over". Next morning at the hall, I signed in at about #1100 on book 2. The ride was good while it lasted.

I always liked Vegas for the fact that if you can bend pipe, you normally had a good job. So did some nice work at City Center (the locals call it City Cemetary), the Titanium plant, and some other casino's. Be later than 2014 before it comes back.


Hey! 1000 th post! Cool :thumbsup:


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## dronai (Apr 11, 2011)

Fountainebleau - 
Also, Bank of America, the resort's largest lender, refused to provide financing on its committed line of credit for the project around this time; as a result, the resort's operator, Fontainebleau Las Vegas LLC, filed for Chapter 11 bankruptcy protection in June of 2009.[4] *Fontainebleau's owner sued himself*.[5][6] All construction work has stopped on the project, which is about 70 percent complete; the grand opening had been scheduled for October 2009. In July 2009, 


The owner sued himself !!!!! That's interesting. What do you win ?


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## Rockyd (Apr 22, 2007)

dronai said:


> Fountainebleau -
> Also, Bank of America, the resort's largest lender, refused to provide financing on its committed line of credit for the project around this time; as a result, the resort's operator, Fontainebleau Las Vegas LLC, filed for Chapter 11 bankruptcy protection in June of 2009.[4] *Fontainebleau's owner sued himself*.[5][6] All construction work has stopped on the project, which is about 70 percent complete; the grand opening had been scheduled for October 2009. In July 2009,
> 
> 
> The owner sued himself !!!!! That's interesting. What do you win ?


What happens in Vegas, stays in Vegas!:thumbsup:

That's Vegas Baby!!!:blink::laughing:


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## Shawn23 (Jan 5, 2011)

I would have used #10s for everything and now my ungrounded conductors are #6s. So does that mean that I have to use a #6 for the egc too? I would think that i could atleast drop it one size??


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## Dennis Alwon (May 9, 2009)

Shawn23 said:


> I would have used #10s for everything and now my ungrounded conductors are #6s. So does that mean that I have to use a #6 for the egc too? I would think that i could atleast drop it one size??


If you would have used 10 gauge then went to 6 gauge then the egc is a 1 to 1 proportion. The egc must also be 6 gauge.

10 awg conductors have a 10 awg egc so a 6 awg conductor must have a 6 awg egc. It changes a bit above 10 awg.


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## Shawn23 (Jan 5, 2011)

Dennis Alwon said:


> If you would have used 10 gauge then went to 6 gauge then the egc is a 1 to 1 proportion. The egc must also be 6 gauge.
> 
> 10 awg conductors have a 10 awg egc so a 6 awg conductor must have a 6 awg egc. It changes a bit above 10 awg.


 
I thought that is how it read. Thanks for the help.


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