How many conductors is this?

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sfav8r

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We are running 3 hots and a neutral as power to a bank of control switches. The load side of the switches (4 switches) have 2 wires each as they reverse the direction of the motor depending upon the position of the switch. In summary, we have Red, Black, Blue, White for the feed, then the switch outputs are a total of 8 conductors (2 per switch). How many conductores does this count as? If you count them all, it would be 12 conductors but this doesn't seem realisitc as the switches can only be in one postion at a time so there is no way for more than 4 of the switch conductors to be energied at one time. Is there an exemption for this?

Thanks
 
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sfav8r said:
We are running 3 hots and a neutral as power to a bank of control switches. The load side of the switches (4 switches) have 2 wires each as they reverse the direction of the motor depending upon the position of the switch. In summary, we have Red, Black, Blue, White for the feed, then the switch outputs are a total of 8 conductors (2 per switch). How many conductors does this count as? If you count them all, it would be 12 conductors but this doesn't seem realistic as the switches can only be in one position at a time so there is no way for more than 4 of the switch conductors to be energized at one time. Is there an exemption for this?

Thanks
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If you are trying to get this allowance for box over fill problem it doesn't matter, box fill and derating for current carrying conductors in a raceway are two different requirements as the latter is where you have allowance for not counting all conductors, but for box fill they all count except EGC's if you have them.:happyyes:
 
hurk27 said:
If you are trying to get this allowance for box over fill problem it doesn't matter, box fill and derating for current carrying conductors in a raceway are two different requirements as the latter is where you have allowance for not counting all conductors, but for box fill they all count except EGC's if you have them.:happyyes:
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Yes I was referring to raceway fill.
 
sfav8r said:
Yes I was referring to raceway fill.
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All conductors count for raceway fill, there is often a difference between the total number of conductors and the number of current carrying conductors used for derating. I would use seven current carrying conductors for your application but there is nothing in the code that would say that I am correct.
 
resistance said:
Sorry, i meant note 3
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(3) Equipment grounding or bonding conductors, where installed. shall be included when calculating conduit tubing fill. The actual dimensions of the equipment grounding or bonding conductors (insulated or bare) shall be used in the calculation.

Note 3 referrs to grounding/bonding conductors. Perhaps you could just post the text of the note you're referring to.
 
Just to further clarify, I'm concerned with the derating (over 9 conductors). 310.15(B) requires derating for "current carrying" conductors, but not all of the conductors in this situation can carry current at the same time due to the switching configuration.
 
You count all conductors for raceway fill but if you are talking about derating for the number of conductors in a conduit then I would not count both the forward and reverse conductors- just count one as the other will not carry current at the same time as the other going to a particular motor.
 
sfav8r said:
(3) Equipment grounding or bonding conductors, where installed. shall be included when calculating conduit tubing fill. The actual dimensions of the equipment grounding or bonding conductors (insulated or bare) shall be used in the calculation.

Note 3 referrs to grounding/bonding conductors. Perhaps you could just post the text of the note you're referring to.
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You are missing the point! I was trying to get you to see that even the non-current carrying conductors count. In a nut shell: All conductors count.
 
Dennis Alwon said:
You count all conductors for raceway fill but if you are talking about derating for the number of conductors in a conduit then I would not count both the forward and reverse conductors- just count one as the other will not carry current at the same time as the other going to a particular motor.
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I will add that the NEC does not allow what I stated but it seems to make sense.
 
sfav8r said:
Just to further clarify, I'm concerned with the derating (over 9 conductors). 310.15(B) requires derating for "current carrying" conductors, but not all of the conductors in this situation can carry current at the same time due to the switching configuration.
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If it’s installed as a current carrying conductor and the conductor is identified ungrounded or could be seen or used as a current carrying conductor (example: Any color but green, white, bare, or gray) then you should include it in your derating calculation.
 
resistance said:
If it?s installed as a current carrying conductor and the conductor is identified ungrounded or could be seen or used as a current carrying conductor (example: Any color but green, white, bare, or gray) then you should include it in your derating calculation.
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Sometimes white or gray need to be counted-- as in 2 wire circuits etc.
 
Dennis Alwon said:
You count all conductors for raceway fill but if you are talking about derating for the number of conductors in a conduit then I would not count both the forward and reverse conductors- just count one as the other will not carry current at the same time as the other going to a particular motor.
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that's what I was getting at. Is there a specific exclusion or do I just need to convince the inspector that this logic makes sense?
 
sfav8r said:
that's what I was getting at. Is there a specific exclusion or do I just need to convince the inspector that this logic makes sense?
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Can we know why this has become a concern. Have you already installed the conductors, and now realize the conductors are derated. Then the question on conduit fill. Are you over the limit? To be honest, I've never seen an inspector doing any calculations in the field. As I was told, and know, there are a few reasons for this. But, if your conduit is over-filled, this may be noticed<<<doesn’t take much to figure this out. Derating is more your responsibility—just the same as voltage drop!! Not sure an inspector is going to waste time trying to figure out this calculation. In any case, you should be designing your install to meet code, and to ensure a safe and reliable installation!
 
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sfav8r said:
that's what I was getting at. Is there a specific exclusion or do I just need to convince the inspector that this logic makes sense?
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The logic make sense and we had this problem with 3-way travelers as I felt the same that only one traveler is used at any one time, but unfortunately this is not spelled out in the code, but I have pointed out that in 220 we don't use the load from air conditioners and electric heat if they can't run at the same time by design, and a few inspectors opened there mind enough and accepted it, and even the state at one time was going to adopt this point of view but it never was followed through on it, so we still have some inspectors who will enforce counting both travelers as current carrying conductors when applying derating rules.
 
Just a question:

Is there anyone who has seen any proposals to this and if so do we know what the panels response to it was as to why it wasn't adopted?? it could lead to a clue as to how it is interpreted in the NEC?

I thought I remember it being brought up before at a IAEI/NFPA meeting before?
 
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