# how many current carrying conducters



## alex42 (Jun 20, 2012)

How many current carrying conducters in 1/2 IN metal conduit if ambiental temperature is more than 90F?


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## alex42 (Jun 20, 2012)

Hoe many #12 AWG current carrying conducters in 1/2 IN metal conduit if ambiental temperature is more than 90F?


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## Bbsound (Dec 16, 2011)

Eleventeen

You may want to provide some more details, or clarify your question. It cannot be answered as you asked.


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## wildleg (Apr 12, 2009)

your profile says you are a jman. I'm just very curious why you are asking. what do you come up with ?


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## Wirenuting (Sep 12, 2010)

Based on your question my answer is 29 with a hammer. 
Just don't energize any of them.


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## Bulldog1 (Oct 21, 2011)

Wirenuting said:


> Based on your question my answer is 29 with a hammer.
> Just don't energize any of them.


Pssttt...you start losing strength in your hands as you age. Thus an old timer like you would need a hammer. Someone young and dumb like me could get 32 in there with out a hammer. At least 39 with a hammer. :laughing:


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## HARRY304E (Sep 15, 2010)

Bulldog1 said:


> Pssttt...you start losing strength in your hands as you age. Thus an old timer like you would need a hammer. Someone young and dumb like me could get 32 in there with out a hammer. At least 39 with a hammer. :laughing:


I'll bet you could get 42 with a little soap..:laughing:


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## erics37 (May 7, 2009)

I've done this experiment with a 12" long piece of 1/2" EMT. I think we got 19 wires jammed in there, but I don't remember if they were #12s or #14s.


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## alex42 (Jun 20, 2012)

*curent carrying conductors*

I want to instal two 20A GFCI receptacles..can I run 1/2 In metal conduit to install them. I`m gonna have 2 hot, 2 neutral and 2 ground on that raceway but my ambiental temperature is more than 110F
I`m sorry my English is bad I`ve try to explaine as best as I can
Thanks


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## alex42 (Jun 20, 2012)

I`ve forgat to say that my question is after temperature deratin how many current carying conductors may I have on 1/2 In metal conduit


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## Bulldog1 (Oct 21, 2011)

erics37 said:


> I've done this experiment with a 12" long piece of 1/2" EMT. I think we got 19 wires jammed in there, but I don't remember if they were #12s or #14s.



The maximum number of conductors if we are talking code wise is 12 #14's and 9 #12's. I would of thought you could get more than 19 in it.... If I wasn't so preoccupied posting on here ( otherwise known as avoiding doing my daily paperwork....:whistling2 I would go verify your number. :laughing:


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## Wirenuting (Sep 12, 2010)

Bulldog1 said:


> Pssttt...you start losing strength in your hands as you age. Thus an old timer like you would need a hammer. Someone young and dumb like me could get 32 in there with out a hammer. At least 39 with a hammer. :laughing:


LoL, your right.
But someone as old as me and as smart as me would be sitting there watching a strong young person like yourself pounding 39 into that TW.


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## alex42 (Jun 20, 2012)

I`m from France we are not using NEC code but I`m work in Iraq and we using here only US NEC and I`m a little confused with temperature derating
Thanks..


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## erics37 (May 7, 2009)

alex42 said:


> I want to instal two 20A GFCI receptacles..can I run 1/2 In metal conduit to install them. I`m gonna have 2 hot, 2 neutral and 2 ground on that raceway but my ambiental temperature is more than 110F
> I`m sorry my English is bad I`ve try to explaine as best as I can
> Thanks


You have 4 current-carrying conductors. If the temperature is 110 degrees fahrenheit and you're using #12 conductors with 90 degree insulation you'll be fine, just barely. I get a calculated ampacity of 20.88, but since you're (probably) limited to a 20 amp breaker you'll be okay.

If the temperature is any higher then there might be issues.


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## alex42 (Jun 20, 2012)

*current carrying conductor*

Thats correct Sir
I`m limited with 20A breaker and I`m working in Iraq. Temperature here at summer time is a way higher than 110F


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## Bulldog1 (Oct 21, 2011)

alex42 said:


> I`ve forgat to say that my question is after temperature deratin how many current carying conductors may I have on 1/2 In metal conduit





#12 thhn 90 degree 30 amps
4 CCC's derate by .70% = 21 amps
21 amps with correction factor of .88 for (96F-104F) =18.48
Next size up = 20 amp OCPD


OOPS 110 degree correction = 21 x .82 = 17.22
Same result


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## Wirenuting (Sep 12, 2010)

A quick guide per the PM I sent.


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## Bulldog1 (Oct 21, 2011)

Wirenuting said:


> LoL, your right.
> But someone as old as me and as smart as me would be sitting there watching a strong young person like yourself pounding 39 into that TW.



I may be young and dumb.......BUT......I figured out long ago that I wanted to be the one watching a strong young or old and wise employee doing the work rather than me doing it.... In reality I try to spend at least a half day in the field working.


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## Wirenuting (Sep 12, 2010)

Bulldog1 said:


> I may be young and dumb.......BUT......I figured out long ago that I wanted to be the one watching a strong young or old and wise employee doing the work rather than me doing it.... In reality I try to spend at least a half day in the field working.


I don't remember being young & dumb.
I have CRS... (can't remember sh/t)

Been 95 these past 3 days & I've been on a roof.
Luckily it will be real cool after today. But I finish the job this afternoon. And here I love my job.


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## Bulldog1 (Oct 21, 2011)

Wirenuting said:


> I don't remember being young & dumb.
> I have CRS... (can't remember sh/t)
> 
> Been 95 these past 3 days & I've been on a roof.
> Luckily it will be real cool after today. But I finish the job this afternoon. And here I love my job.



Seems like every time we have roof work its 100 degrees and no shade. The day after we finish it will be 75 and a slight breeze.... I'd lend you one of the umbrellas I bought for outside work if you were here. :thumbsup:

I'm not so young anymore.....and it's possible I've gotten and or am getting dumber.....:laughing:


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## don_resqcapt19 (Jul 18, 2010)

Bulldog1 said:


> #12 thhn 90 degree 30 amps
> 4 CCC's derate by .70% = 21 amps
> 21 amps with correction factor of .88 for (96F-104F) =18.48
> Next size up = 20 amp OCPD
> ...


 The derate for 4 CCCs is .8. Table 310.15(B)(3)(a). 
That still comes up less than 20 amps and you cannot use the next size up for a circuit that supplies more than one receptacle.


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## wildleg (Apr 12, 2009)

alex42 said:


> Thats correct Sir
> I`m limited with 20A breaker and I`m working in Iraq. Temperature here at summer time is a way higher than 110F


1) you use table 9 for the type of conduit to get # conductors (the easy way, or you can calculate the conductor fill) ("metal conduit" is not one of the choices. what type of raceway are you using ?)

2) based on the number of current carrying conductors, you use table 310.15 B 2 a to find the allowable ampacity of your conductors

3) you have to use the temperature correction factors (bottom of tables in 310.16) to correct the allowable ampacity for the Maximum ambient temperature. repeat Maximum temperature.

that gives you your final allowable ampacity. then you have to protect the conductors at that ampacity according to article 240, or whatever special conditions or equipment apply to your situation.


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## Bulldog1 (Oct 21, 2011)

don_resqcapt19 said:


> The derate for 4 CCCs is .8. Table 310.15(B)(3)(a).
> That still comes up less than 20 amps and you cannot use the next size up for a circuit that supplies more than one receptacle.




Your correct about the .80. However give me a break I did that by memory and I ain't that smart as you can see.......plus I'm on a jobsite..:laughing: Almost all the calcs I do have more than 7 ccc which is .70. 

The code actually says "multi outlet branch circuit supplying receptacles for cord and plug connected portable loads." Did he say if his receptacles were for portable loads? I'm sure they are but if not then he could use the next size up. Thanks Don.


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## alex42 (Jun 20, 2012)

Thank you guys..I have one more question:
My SDP is 125A and I`m using 100A main breaker. Can I use #6 grounding wire to connect my panel to the ground rod or gotta use bigger size of grounding wire?


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## Hippie (May 12, 2011)

alex42 said:


> Thank you guys..I have one more question:
> My SDP is 125A and I`m using 100A main breaker. Can I use #6 grounding wire to connect my panel to the ground rod or gotta use bigger size of grounding wire?


Wire to ground rods never has to be more than #6


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## Electricianguy (Jun 17, 2012)

9 # 12awg if that helps


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## erics37 (May 7, 2009)

The multiplier for 110 degrees fahrenheit is .87 for 90 degree insulation.

30 amps x .87 x .8 = 20.88 amps.

It's fine on a 20 amp breaker unless the temperature goes up.


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## frenchelectrican (Mar 15, 2007)

alex42 said:


> Thank you guys..I have one more question:
> My SDP is 125A and I`m using 100A main breaker. Can I use #6 grounding wire to connect my panel to the ground rod or gotta use bigger size of grounding wire?


Oui., Vous pouvez utiliser le * 6 AWG ou 16mm2 

( Yes., You can use the #6 awg or 16mm2 ) 

Merci,
Marc


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## Bulldog1 (Oct 21, 2011)

erics37 said:


> The multiplier for 110 degrees fahrenheit is .87 for 90 degree insulation.
> 
> 30 amps x .87 x .8 = 20.88 amps.
> 
> It's fine on a 20 amp breaker unless the temperature goes up.


Did you even read my or code guru dons posts? I see .82 for 110 degrees in 2008.


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## Dennis Alwon (May 9, 2009)

Bulldog1 said:


> Did you even read my or code guru dons posts? I see .82 for 110 degrees in 2008.



It is .87 for 90C wire


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## Bulldog1 (Oct 21, 2011)

Dennis Alwon said:


> It is .87 for 90C wire


I was looking at a pdf online. since I didn't have a code book. It must be wrong. It shows .82


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## A Little Short (Nov 11, 2010)

don_resqcapt19 said:


> The derate for 4 CCCs is .8. Table 310.15(B)(3)(a).
> That still comes up less than 20 amps and you cannot use the next size up for a circuit that supplies more than one receptacle.


You're slipping Don!



erics37 said:


> The multiplier for 110 degrees fahrenheit is .87 for 90 degree insulation.
> 
> 30 amps x .87 x .8 = 20.88 amps.
> 
> It's fine on a 20 amp breaker unless the temperature goes up.


:thumbsup:


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## Bulldog1 (Oct 21, 2011)

Little-Lectric said:


> You're slipping Don!
> 
> :thumbsup:


He still has to derate for the 4 ccc's..........
Don pretty much nailed it as far as overcurrent protection if the receptacles are for portable loads.


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## don_resqcapt19 (Jul 18, 2010)

I did not look up the temperature correction factor. With a correction factor of .87 and 4 current carrying conductors, you are good to go with a 20 amp OCPD no matter what the load is.


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## Dennis Alwon (May 9, 2009)

Bulldog1 said:


> I was looking at a pdf online. since I didn't have a code book. It must be wrong. It shows .82


 .82 is for 75C


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## wildleg (Apr 12, 2009)

he said it was way above 110. he never gave the maximum ambient temp


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## don_resqcapt19 (Jul 18, 2010)

wildleg said:


> he said it was way above 110. he never gave the maximum ambient temp


 Anything above 113°F would be an issue. The ampacity of the condcutors would drop below 20.


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## acelectric44 (Jul 3, 2012)

just curious why you are pulling 2 grounds?


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## Aegis (Mar 18, 2011)

I remember not counting neutrals when doing this, in the CEC 4-004 (3). Is the NEC different or am I losing it?


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## erics37 (May 7, 2009)

Aegis said:


> I remember not counting neutrals when doing this, in the CEC 4-004 (3). Is the NEC different or am I losing it?


In the NEC, neutrals don't count if they're only carrying the unbalanced load of a circuit. Exceptions are for circuits utilizing 2 legs and a neutral from a Wye system, because the phase currents don't cancel.


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## tates1882 (Sep 3, 2010)

The ambient temperature should be figured from the ASHREA hand book on fundamentals.


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