Mixed wiring

[William M. Fossier Jr.]

Can anyone tell me where it is in NEC that defines that attaching a 12 and 14 guage wire with a nut with a lead to a 15a breaker is not proper.

Thank You

[Bruce A. King]

It is ok but it might be considered to use a 14ga wire on the breaker to help prevent someone from replacing the 15a breaker with a 20a someday.

[Paul W. Abernathy]

Think of it this way...so it helps you in the future...

The intent of the OCPD is to protect the wire itself......so you have to protect the weakest link in the install...in this case the #14 AWG(15A) is smaller than the # 12 AWG(20A)...so when you think of OCPD..protect the smallest....

Update: I am sorry....OCPD = Overcurrent Protection Device ( ie: Breaker & Fuses )

[jtedesco1]

Originally Posted by bking

It is ok but it might be considered to use a 14ga wire on the breaker to help prevent someone from replacing the 15a breaker with a 20a someday.

Bruce: I agree, someone would think that the 12 AWG could be protected by a 20 amp breaker.



Reference:

NEC 2005, Section 210.3 Rating. Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or setting of the overcurrent device. The rating for other than individual branch circuits shall be 15, 20, 30, 40, and 50 amperes.

Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified over-current device shall determine the circuit rating.

[Joey D'Adamo]

What about cases where the home run is very long and is upsized one gauge, while the rest of the circuit is in the expected guage?

Honestly it is always a risk and designing a system to protect idiots is not usually a design consideration. A professional would know better and isn't that what's important?

[Joe Farsetta]

You cannot report on things you cannot see or know to be true. If, in fact, a #12 wire ran a ways inside the wall, and branched off into #14's, there wouldnt be any real way to tell, other than to look at a switch or receptacle in a way that exceeds the SOP for a home inspection. If you got lucky, and saw a j-box in the attic where these downsized conductors were attached, you could note it, but if the breaker was rated at 15amps, there would be no problem.

[Paul W. Abernathy]

lol.....I think I explained the condition of placing a 15A breaker on a 20A Circuit if tapped to a 15A conductor ( ie: 14 AWG)...lol.....

I think the question was can you pigtail it...lol...from a 14 AWG to a 12 AWG....while it is allowed to increase the wires size you still have to protect for the weakest link...in this case the 14 AWG...regardless

Joey- we do this alot...but in applications mostly that have a extreme distance issues, in a dwelling if their is a slight distance issue it is easier to just install the entire run in 12 AWG.....most other normal applications will not require this...

However, I just did the electrical layout on a 4,500 sq ft house that will need a 400A service.......at the point of entry we have a 200A Sq D QO Panel and a Sq D 200A Disconnect.......that disconnect is feeding a 200A panel located in another part of the house.....WHY.....to reduce the voltage drop and reduce the length of runs...example is the kitchen was on the opposite side of the house of the service entrance location......

Costs less to do it that way than to pay for larger wire and so on to meet the longer run from the panel to the kitchen....so it works out less in the end...but ...not sure why I rambled on about that...sorry

While I think the pigtail should be 14 AWG to match conductor