How many 20 amp circuits in 2" EMT?

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  #1  
Old 12-11-04, 09:23 AM
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How many 20 amp circuits in 2" EMT?

How many 20 amp circuits can I run in 2" EMT?
Assuming 12 ga solid wire with ground?
Can bare ground wires be run in EMT or do they have to be insulated?
Many thanks!
Bill
 
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  #2  
Old 12-11-04, 09:42 AM
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9 current carrying conductors then you have to start derating. If you use mulitwire circuits you could have 6 circuits. Ground wire doesn't count as current carrying.
 
  #3  
Old 12-11-04, 02:33 PM
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As Joe said, the limitation is not based on the size of the conduit, but on the ampacity of the wires. The answer is the same for 3/4" conduit or 4" conduit. So you could run four regular 20-amp circuits (four hots and four neutrals), or three multiwire 20-amp circuits (six hots and three neutrals). Yes, the grounding wire can be bare.
 
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Old 12-12-04, 07:06 AM
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And you can't use NM-B cable.
 
  #5  
Old 12-12-04, 11:22 AM
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Thanks, but...

Many thanks for all of your comments, but, I'm still not clear on how to calculate how many 12 ga/20 amp circuits can be used in 2" EMT.

Is there a web link that will help me understand fill capacity and de-rating?

Tnx
Bill
 
  #6  
Old 12-12-04, 03:03 PM
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The answer is four.

Coming up with that answer involves blending a dozen or more parts of the electrical code. There are lots of considerations. However, for purposes of your question, one consideration is paramont. That is the code dealing with ampacity derating. Once you get more than nine current carrying conductors in the same conduit (of any size), 12-gauge wire is no longer good for a 20-amp circuit. This consideration trumps considerations of conduit fill, which would have let you put more than 100 wires in that 2" EMT.
 
  #7  
Old 12-12-04, 08:39 PM
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Thanks your response

John,
Many thanks for taking the time to respond to my question.
I think it would be best to abandon my use of the 2" EMT for this project
Bill
 
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