# Poll: How Many Conductors in Conduit



## local134gt (Dec 24, 2008)

What voltage are the wall heaters?


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## 360max (Jun 10, 2011)

local134gt said:


> What voltage are the wall heaters?


I edited question


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## HackWork (Oct 2, 2009)

12..


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## 8V71 (Dec 23, 2011)

..6..


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## BBQ (Nov 16, 2010)

220? This sounds like a DIY question.


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## SteveBayshore (Apr 7, 2013)

Brain teaser. When calculating loads, only need to use larger of two loads because only heat or A/C would be used at any one time. Using that assumption, I would say 6 conductors for derating. Only heat or A/C conductors would be current carrying at any given time. 
But then again, I've been in offices where the A/C is up so high that the office people have to turn on the heat to compensate.


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## BBQ (Nov 16, 2010)

I agree with Steve, it really depends on the specifics of the job.

It could be 6 or it could be 12.


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## 360max (Jun 10, 2011)

BBQ said:


> I agree with Steve, it really depends on the specifics of the job.
> 
> It could be 6 or it could be 12.


the specifics of the job where given in post 1


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## FastFokker (Sep 18, 2012)

Wtf kind of poll is this... keeps getting edited, but never for clarification. 

I say 6.. unless it said both heating and cooling could be used at the same time.


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## Dennis Alwon (May 9, 2009)

All the wires are current carrying conductor's .


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## BBQ (Nov 16, 2010)

360max said:


> the specifics of the job where given in post 1


OK Cletis. :laughing::laughing:


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## 360max (Jun 10, 2011)

BBQ said:


> OK Cletis. :laughing::laughing:


:laughing::laughing::laughing:


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## Cletis (Aug 20, 2010)

360max said:


> In a residential setting
> supply 6 ckts: 3- 208v single phase air conditioners and 3- 208v single phase base board electric heaters
> 
> Install 6 wires in conduit for three, 208v air conditioners. In same conduit, 6 wires are installed for 208v wall heaters. How many current carrying conductors are in the conduit?


Im working hard on conduit vs seu job now. Will figure tonight


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## don_resqcapt19 (Jul 18, 2010)

360max said:


> the specifics of the job where given in post 1


Not enough to say if the answer is 6 or 12....


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## 360max (Jun 10, 2011)

FastFokker said:


> Wtf kind of poll is this... keeps getting edited, but never for clarification.
> 
> I say 6.. unless it said both heating and cooling could be used at the same time.


its running 6 ckts, in the same conduit, from a residential panel, where is the mystery? Each ckt gets terminated to its own 2 pole circuit breaker


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## 360max (Jun 10, 2011)

12 wires / 2 wires per ckt = 6 (2 pole) ckts


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## 360max (Jun 10, 2011)

don_resqcapt19 said:


> Not enough to say if the answer is 6 or 12....


what is missing?


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## bkmichael65 (Mar 25, 2013)

It don't think it matters if they are coincidental loads or not. I say all of them are current carrying


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## 360max (Jun 10, 2011)

Cletis said:


> Im working hard on conduit vs seu job now. Will figure tonight


knew you'd come to the rescue, thanks!


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## Dennis Alwon (May 9, 2009)

Given the info- they are all current carrying conductor and you would have to count all for derating. Now can 220.66 come into play if there is no way to insure that the a/c and heat cannot cannot on together. That would be hard to do with baseboard and a separate a/c system.


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## 360max (Jun 10, 2011)

can someone post 220.66, dont have book with me?


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## Cletis (Aug 20, 2010)

360max said:


> can someone post 220.66, dont have book with me?


(B) Permitted Reductions. A service or feeder supplying the following loads shall be permitted to have an additional demand factor of 70 percent applied to the amount in 220.61(B)(1) or portion of the amount in 220.61(B)(2) determined by the basic calculation:
(1) 
A feeder or service supplying household electric ranges, wall-mounted ovens, counter-mounted cooking units, and electric dryers, where the maximum unbalanced load has been determined in accordance with Table 220.55 for ranges and Table 220.54 for dryers
(2) 
That portion of the unbalanced load in excess of 200 amperes where the feeder or service is supplied from a 3-wire dc or single-phase ac system; or a 4-wire, 3-phase, 3-wire, 2-phase system; or a 5-wire, 2-phase system


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## jw0445 (Oct 9, 2009)

*220.61 Feeder or Service Neutral Load.
(A) Basic Calculation.​*​​​​The feeder or service neutral load
shall be the maximum unbalance of the load determined by
this article. The maximum unbalanced load shall be the
maximum net calculated load between the neutral conductor
and any one ungrounded conductor.​
_Exception: For 3-wire, 2-phase or 5-wire, 2-phase systems,
the maximum unbalanced load shall be the maximum
net calculated load between the neutral conductor and any
one ungrounded conductor multiplied by 140 percent.​_*(B) Permitted Reductions.​*​​​​A service or feeder supplying
the following loads shall be permitted to have an additional
demand factor of 70 percent applied to the amount in
220.61(B)(1) or portion of the amount in 220.61(B)(2) determined
by the basic calculation:
(1) A feeder or service supplying household electric ranges,
wall-mounted ovens, counter-mounted cooking units, and
electric dryers, where the maximum unbalanced load has
been determined in accordance with Table 220.55 for
ranges and Table 220.54 for dryers
(2) That portion of the unbalanced load in excess of 200 amperes
where the feeder or service is supplied from a
3-wire dc or single-phase ac system; or a 4-wire, 3-phase,
3-wire, 2-phase system; or a 5-wire, 2-phase system​
*(C) Prohibited Reductions.​*​​​​There shall be no reduction of
the neutral or grounded conductor capacity applied to the
amount in 220.61(C)(1), or portion of the amount in (C)(2),
from that determined by the basic calculation:
(1) Any portion of a 3-wire circuit consisting of 2 ungrounded
conductors and the neutral conductor of a
4-wire, 3-phase, wye-connected system
(2) That portion consisting of nonlinear loads supplied
from a 4-wire, wye-connected, 3-phase system​
Informational Note No. 1: See Examples D1(a), D1(b),
D2(b), D4(a), and D5(a) in Informative Annex D.
Informational Note No. 2: A 3-phase, 4-wire, wye-connected
power system used to supply power to nonlinear loads may
necessitate that the power system design allow for the possibility
of high harmonic neutral-conductor currents.​*IV. Optional Feeder and Service Load Calculations
220.80 General.​*​​​​Optional feeder and service load calculations
shall be permitted in accordance with Part IV.​
*220.82 Dwelling Unit.
(A) Feeder and Service Load.​*​​​​This section applies to a
dwelling unit having the total connected load served by a
single 120/240-volt or 208Y/120-volt set of 3-wire service
or feeder conductors with an ampacity of 100 or greater. It
shall be permissible to calculate the feeder and service
loads in accordance with this section instead of the method
specified in Part III of this article. The calculated load shall
be the result of adding the loads from 220.82(B) and (C).
Feeder and service-entrance conductors whose calculated
load is determined by this optional calculation shall be permitted
to have the neutral load determined by 220.61.​
*(B) General Loads.​*​​​​The general calculated load shall be
not less than 100 percent of the first 10 kVA plus 40 percent
of the remainder of the following loads:
(1) 33 volt-amperes/m2 or 3 volt-amperes/ft2 for general
lighting and general-use receptacles. The floor area for
each floor shall be calculated from the outside dimensions
of the dwelling unit. The calculated floor area
shall not include open porches, garages, or unused or
unfinished spaces not adaptable for future use.
(2) 1500 volt-amperes for each 2-wire, 20-ampere smallappliance
branch circuit and each laundry branch circuit
covered in 210.11(C)(1) and (C)(2).
(3) The nameplate rating of the following:
a. All appliances that are fastened in place, permanently
connected, or located to be on a specific circuit
b. Ranges, wall-mounted ovens, counter-mounted cooking
units
c. Clothes dryers that are not connected to the laundry
branch circuit specified in item (2)
d. Water heaters
(4) The nameplate ampere or kVA rating of all permanently
connected motors not included in item (3).​
*(C) Heating and Air-Conditioning Load.​*​​​​The largest of
the following six selections (load in kVA) shall be included:
(1) 100 percent of the nameplate rating(s) of the air conditioning
and cooling.
(2) 100 percent of the nameplate rating(s) of the heat pump
when the heat pump is used without any supplemental
electric heating.
(3) 100 percent of the nameplate rating(s) of the heat pump
compressor and 65 percent of the supplemental electric
heating for central electric space-heating systems. If the​
heat pump compressor is prevented from operating at


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## Fibes (Feb 18, 2010)

Try 220.60


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## Dennis Alwon (May 9, 2009)

360max said:


> can someone post 220.66, dont have book with me?



Actually 220.60 --- not 220.66-- my mistake-- that is for calculating non-coincidental loads- those which cannot be on at the same time



> 220.60 Noncoincident Loads. Where it is unlikely that
> two or more noncoincident loads will be in use simultaneously,
> it shall be permissible to use only the largest
> load(s) that will be used at one time for calculating the total
> load of a feeder or service.


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## SteveBayshore (Apr 7, 2013)

Dennis Alwon said:


> Actually 220.60 --- not 220.66-- my mistake-- that is for calculating non-coincidental loads- those which *cannot* be on at the same time


Code says "unlikely" not impossible to operate simultaneously. Still not pertaining to conductor derating, but I would argue for six conductors.


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## BBQ (Nov 16, 2010)

I don't see anything in this section that says we count more conductors as current carrying than can actually carry current at the same time.



> 310.15(B)(3) Adjustment Factors.
> (a) More Than Three Current-Carrying Conductors in a
> Raceway or Cable. Where the number of current-carrying
> conductors in a raceway or cable exceeds three, or where
> ...


It is my opinion that if the heat and cooling are interlocked so that only one or the other can be used at the same time we only have to count the conductors that can run at the same time.


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## pudge565 (Dec 8, 2007)

FastFokker said:


> Wtf kind of poll is this... keeps getting edited, but never for clarification.
> 
> I say 6.. unless it said both heating and cooling could be used at the same time.


Unless they are interlocked in some way of course they can be used at the same time, will they be, probably not but you as an installer do not know that.


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## don_resqcapt19 (Jul 18, 2010)

I am going to change my mind based on another look at the code. No additional information is required. There is no provision in the current code that permits you to not count installed conductors that are not EGCs or non-current carrying grounded conductors. 
Look at the text following the derating table.


> 1Number of conductors is the total number of conductors in the raceway or cable adjusted in accordance with 310.15(B)(5) and (6).


This will be addressed in the 2014 code. The following is the text that follows the derating table in the draft of the 2014 code.


> Number of conductors is the total number of conductors in the raceway or cable, including spare conductors. The count shall be adjusted in accordance with 310.15(B)(5) and (6), and shall not include conductors that are connected to electrical components but that cannot be simultaneously energized. [ROP 6–40]


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## HackWork (Oct 2, 2009)

I've heard a few different guys complain that their daughters turn the baseboard heat up in the Summer because the AC is making it too cold in their bedroom.


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## Fibes (Feb 18, 2010)

HackWork said:


> I've heard a few different guys complain that their daughters turn the baseboard heat up in the Summer because the AC is making it too cold in their bedroom.


I know it's not quite the same but, we have a girl in our office that will have a space heater running under her desk in the midddle of July with the AC trying to keep up


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## 360max (Jun 10, 2011)

IMO the answer is 12 CCC, as the heat and AC are on separate circuits, making them all current carrying conductors.

I also believe three way switches have 3 CCC, as the code does not state when they are current carrying conductors, but only if they are CCC. Don had posted the upcoming code change that addresses this.


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## BBQ (Nov 16, 2010)

360max said:


> IMO the answer is 12 CCC, as the heat and AC are on separate circuits, making them all current carrying conductors.


I am sticking with 6 if the loads are mutually exclusive.




don_resqcapt19 said:


> There is no provision in the current code that permits you to not count installed conductors that are not EGCs or non-current carrying grounded conductors.





360max said:


> I also believe three way switches have 3 CCC, as the code does not state when they are current carrying conductors, but only if they are CCC. Don had posted the upcoming code change that addresses this.



Funny that the CMP saw it differently for the 2008 NEC. 




> *6-50 Log #1405 NEC-P06 Final Action: Reject
> (310.15(B)(2)(a), Exception No. 6 (New))*
> ____________________________________________________________
> *Submitter:* George Stolz, II, Pierce, CO
> ...


:thumbsup:


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## don_resqcapt19 (Jul 18, 2010)

BBQ said:


> I am sticking with 6 if the loads are mutually exclusive.
> Funny that the CMP saw it differently for the 2008 NEC.
> 
> :thumbsup:


They must of changed their mind...the text below Table 310.15(B)(3)(a) was new for the 2011 code.
The following is part of the substantiation for the new text.


> This Table was originally added to the Code in 1940 and the column heading remained as “Number of Conductors” until 1993. During the 1993 NEC revision cycle, the column headings in Table 310.15(B)(2)(a) and Table B.310.11 were editorially changed to “Number of Current-Carrying Conductors”. There was no Proposal, Comment, or Panel Action to make the change. ...


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## HackWork (Oct 2, 2009)

Fibes said:


> I know it's not quite the same but, we have a girl in our office that will have a space heater running under her desk in the midddle of July with the AC trying to keep up


Yup, I've known women in offices to wear coats during the Summer because 75 degrees was too cold.


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## HackWork (Oct 2, 2009)

BBQ said:


> I am sticking with 6 if the loads are mutually exclusive.


How are the loads in question mutually exclusive?


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## BBQ (Nov 16, 2010)

HackWork said:


> How are the loads in question mutually exclusive?


I have no idea if they are or not, that is why the word 'if' is in that sentence and why I have been trying to get 360 to provide more info. :thumbsup:


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## 360max (Jun 10, 2011)

BBQ said:


> I am sticking with 6 if the loads are* mutually exclusive.*


...define what you mean by 'mutually exclusive'


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## 360max (Jun 10, 2011)

It is a STANDARD RESIDENTIAL INSTALL, there are NOT INTERLOCKS:jester: on the 6 different breakers (3 for heat, and 3 for AC)


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## BBQ (Nov 16, 2010)

360max said:


> ...define what you mean by 'mutually exclusive'


They cannot run at the same time.


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## BBQ (Nov 16, 2010)

360max said:


> It is a STANDARD RESIDENTIAL INSTALL, there are NOT INTERLOCKS:jester: on the 6 different breakers (3 for heat, and 3 for AC)


A typical forced air furnace equipped with a cooling coil is usually interlocked via the T-stat, it will not allow both heat and cool to run at the same time.

That said if you are telling me they can run at the same time IMO there is no doubt the number of CCCs would be 12.


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## 360max (Jun 10, 2011)

BBQ said:


> A typical forced air furnace equipped with a cooling coil is usually interlocked via the T-stat, it will not allow both heat and cool to run at the same time.
> 
> That said if you are telling me they can run at the same time IMO there is no doubt the number of CCCs would be 12.


does your scenario run on 6 different 2 pole breakers like mine?



supply 6 ckts: 3- 208v single phase air conditioners and 3- 208v single phase *base board electric heaters*


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## BBQ (Nov 16, 2010)

360max said:


> does your scenario run on 6 different 2 pole breakers like mine?


It could, or it could have a two pole for the outdoor condenser and single pole for the 120 volt furnace. Same number of conductors either way.



But what are you getting at with this thread, you seem to have a very specific installation in mind and are just trolling until you feel like giving the rest of the info. It is very Cletis so far. :whistling2:


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## bkmichael65 (Mar 25, 2013)

360max said:


> does your scenario run on 6 different 2 pole breakers like mine?
> 
> 
> 
> supply 6 ckts: 3- 208v single phase air conditioners and 3- 208v single phase *base board electric heaters*


Interlocks lock out the control wiring, not the individual branch circuits. You usually only see them with heat pump/furnace configurations, but you could still install them in this case


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## 360max (Jun 10, 2011)

I made the mistake in the first post, where I should have given better detail with stamped drawings, with the specs for the install for the AC, specs for the install on the base board heaters, specs for the panel used, and pics of the set up in the panel. I forgot this is ET :whistling2:


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## wildleg (Apr 12, 2009)

360max said:


> .* How many current carrying conductors are in the conduit*?


too many (unless 50% floats your boat)


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## 360max (Jun 10, 2011)

wildleg said:


> too many (unless 50% floats your boat)


it is a scenario for discussion only, not a real install.


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## brian john (Mar 11, 2007)

don_resqcapt19 said:


> Not enough to say if the answer is 6 or 12....


7 or 13 depending if you believe a copper EGC musty be pulled. Just saying.


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## don_resqcapt19 (Jul 18, 2010)

brian john said:


> 7 or 13 depending if you believe a copper EGC musty be pulled. Just saying.


The pole says "current carrying conductors".


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## Celtic (Nov 19, 2007)

360max said:


> it is a scenario for discussion only, not a real install.


Then just run some NM ...


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## drspec (Sep 29, 2012)

where are you getting 208v residential service?


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## Celtic (Nov 19, 2007)

drspec said:


> where are you getting 208v residential service?



hi rise


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## mdfriday (May 14, 2007)

I say forget that hole scenario. Pull 6 total conductors and put a couple contactors at the end. Feed off those to the heat / cool. 2 poles NO, 2 poles NC.........

SO I vote 6 with my value engineering......


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## irocin350 (Mar 2, 2011)

I would say 6 , because its being supplies by 6 ckts meaning each 2pole will serve 1ac &1 wall heater at the same time witch is ok there for they are non-coincidental loads


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## pudge565 (Dec 8, 2007)

irocin350 said:


> I would say 6 , because its being supplies by 6 ckts meaning each 2pole will serve 1ac &1 wall heater at the same time witch is ok there for they are non-coincidental loads


How do you get that? He said 6 wires for the A/C and 6 wires for the wall heaters, one 2 pole is a circuit.


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## bkmichael65 (Mar 25, 2013)

irocin350 said:


> I would say 6 , because its being supplies by 6 ckts meaning each 2pole will serve 1ac &1 wall heater at the same time witch is ok there for they are non-coincidental loads


Better read it again


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## A Little Short (Nov 11, 2010)

Until the 2014 comes out and the section that Don quoted is in effect, there is currently no language that says conductors for noncoincident loads are exempt from being counted as CCCs.

220.60 is for service load calculations, not for determining whether a conductor is a CCC.

True, both loads probably won't be on at the same time, but I still see no reduction for number of CCC.


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## irocin350 (Mar 2, 2011)

pudge565 said:


> How do you get that? He said 6 wires for the A/C and 6 wires for the wall heaters, one 2 pole is a circuit.


Easy his supply is 6 ckts that means 6 breaker spots not 6 2 pole breaker spots then u install 3. 2 pole breakers and then u parallel 1 Ac & 1 heater on the load side of the breaker , since 1 is heat & 1 is Ac those r non coincidental loads ,only 6 of the 12 wires in the conduit r current carrying because they are non coincidental loads / I'm not saying this is good design or good practice but that's how I read the orig question see below




In a residential setting
supply 6 ckts: 3- 208v single phase air conditioners and 3- 208v single phase base board electric heaters

Install 6 wires in conduit for three, 208v air conditioners. In same conduit, 6 wires are installed for 208v wall heaters. How many current carrying conductors are in the conduit?


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## 360max (Jun 10, 2011)

irocin350 said:


> Easy his supply is 6 ckts that means 6 breaker spots not 6 2 pole breaker spots then u install 3. 2 pole breakers and then u parallel 1 Ac & 1 heater on the load side of the breaker , since 1 is heat & 1 is Ac those r non coincidental loads ,only 6 of the 12 wires in the conduit r current carrying because they are non coincidental loads / I'm not saying this is good design or good practice but that's how I read the orig question see below
> 
> 
> 
> ...


:001_huh::001_huh: thats a total of 12 breaker spaces in a panel


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## SteveBayshore (Apr 7, 2013)

360max said:


> It is a STANDARD RESIDENTIAL INSTALL, there are NOT INTERLOCKS:jester: on the 6 different breakers (3 for heat, and 3 for AC)


When does a standard residential install have 208 volt service and get wired in conduit?:blink::blink::blink:


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## irocin350 (Mar 2, 2011)

irocin350 said:


> Easy his supply is 6 ckts that means 6 breaker spots not 6 2 pole breaker spots then u install 3. 2 pole breakers and then u parallel 1 Ac & 1 heater on the load side of the breaker , since 1 is heat & 1 is Ac those r non coincidental loads ,only 6 of the 12 wires in the conduit r current carrying because they are non coincidental loads / I'm not saying this is good design or good practice but that's how I read the orig question see below
> 
> In a residential setting
> supply 6 ckts: 3- 208v single phase air conditioners and 3- 208v single phase base board electric heaters
> ...


Oops I for got to say as long as heat and Ac are electromechanical isolated ie. relays,contactor ect


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