12/3 for multiple circuits

[dcwest]

I have a question about the use of 12/3 wire for feeding two 110v circuits from two breakers @ the load center. (This has been suggested as an exceptable shortcut)

I maintain that feeding two 20a circuits requires two runs of 12/2 for max capacity. If both circuits were drawing 20a and being fed through one 12/3 wire, the heat of two hot wires each carrying 20a would be an issue, not to mention the common carrying the combined 40a.

Am I missing something here?

 

[Buck Parrish]

I have a question about the use of 12/3 wire for feeding two 110v circuits from two breakers @ the load center. (This has been suggested as an exceptable shortcut)

I maintain that feeding two 20a circuits requires two runs of 12/2 for max capacity. If both circuits were drawing 20a and being fed through one 12/3 wire, the heat of two hot wires each carrying 20a would be an issue, not to mention the common carrying the combined 40a.

Am I missing something here?[/quote]


Yes.........................

 

[Rewire]

I have a question about the use of 12/3 wire for feeding two 110v circuits from two breakers @ the load center. (This has been suggested as an exceptable shortcut)

I maintain that feeding two 20a circuits requires two runs of 12/2 for max capacity. If both circuits were drawing 20a and being fed through one 12/3 wire, the heat of two hot wires each carrying 20a would be an issue, not to mention the common carrying the combined 40a.

Am I missing something here?

Yes, you need to contact a qualified electrician to do your install. We do not answer questions from DIY's

 

[iwire]

I direct you gentlemen to here #2

 

[Buck Parrish]

I have a question about the use of 12/3 wire for feeding two 110v circuits from two breakers @ the load center. (This has been suggested as an exceptable shortcut)

I maintain that feeding two 20a circuits requires two runs of 12/2 for max capacity. If both circuits were drawing 20a and being fed through one 12/3 wire, the heat of two hot wires each carrying 20a would be an issue, not to mention the common carrying the combined 40a.

Am I missing something here?

What you have described (12-3) is approoved and is a common wiring method. Their are always variations, though.
See NEC 2008 210.4 A-B-C-D , 210.5 A,B , 210.6 a thru e

 

[iwire]

After PMing the poster and getting more details am closing this thread, in accordance with the Forum Rules.

This site is designed for:

• Contractors
• Electricians
• Engineers
• Inspectors
• Instructors
• Other electrically related individuals

* This NEC? Forum is for those in the electrical and related industries. Questions of a "How-To" nature by persons not involved in the electrical industry will be removed without notice.