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Double Checking Service Entrance Conductor Sizing


randynavarro
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Originally posted by randynavarro

According to my Code Check, if I have copper service wires feeding the 200 amp main panel, they have to be a minimum 3/0.

Anyone have anything different.

Had a 200 amp panel today with only #2 copper.

You're mis-reading the chart. There should be two columns, one for branch circuits and one for service conductors. (They're derived from two different tables in the NEC.)

A 200-amp service conductor or feeder (assuming the proper conductor type) can be wired with 2-0 copper.

- Jim Katen, Oregon

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Originally posted by Jim Katen

You're mis-reading the chart. There should be two columns, one for branch circuits and one for service conductors. (They're derived from two different tables in the NEC.)

A 200-amp service conductor or feeder (assuming the proper conductor type) can be wired with 2-0 copper.

- Jim Katen, Oregon

OK Jim thanks for the clarification, that division isn't state in Code Check. However! I was actually patient and took the time to drudge thru the 2005 NEC and came up with the table 310.15(B)(6) that outlines conductor sizes for single family and multi-family dwellings.

That chart states a minimum conductor size of 2/0 for copper at 200 amps. I've pasted the table into a Word doc here.

Am I still missing something!!

Download Attachment: icon_word.gif Service Entrance Sizes.doc

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Here,

This might be easier to use. I scanned the thing. Save it and then blow it up and print it out on cardstock.

I don't remember where I got it but I can tell you that it's at least 9 years old and shows it after bouncing around in my clipboard for that long.

OT - OF!!!

M.

Download Attachment: icon_photo.gif CableSizes.jpg

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Originally posted by randynavarro

. . . OK Jim thanks for the clarification, that division isn't state in Code Check.

You must be using the old Code Check Electrical (light green). It has the two different charts located nowhere near each other. This makes it confusing. Check out table ET-23 on Page 28.

The newer Code Check Electrical (orange) is organized in a much better way, is clearer and easier to understand and has no errors that I'm aware of. Buy it.

However! I was actually patient and took the time to drudge thru the 2005 NEC and came up with the table 310.15(B)(6) that outlines conductor sizes for single family and multi-family dwellings.

That chart states a minimum conductor size of 2/0 for copper at 200 amps. I've pasted the table into a Word doc here.

Am I still missing something!!

No, I don't believe you are. Congratulations on slugging through the NEC. Once you spend some time with it, it really isn't that bad. There’s a lot of detail and nuance in there that you can't get from Code Check.

- Jim Katen, Oregon

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