12 gauge to the room, 14 for lights and 3-way

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Funwiring

Member
Another common practice where I see (our town has no electrical inspection required) is to feed a room with 12-2 on a 20 amp circuit, feed the receptacles but branch in the switch boxes up to the lights with 14-2 or use 14-3 to run 3-way switches. Is that code acceptable?
 

iwire

Moderator
Staff member
Location
Massachusetts
Funwiring said:
feed a room with 12-2 on a 20 amp circuit, feed the receptacles but branch in the switch boxes up to the lights with 14-2 or use 14-3 to run 3-way switches. Is that code acceptable?

No.

240.4(D) for a start.
 

Brady Electric

Senior Member
Location
Asheville, N. C.
12 gauge to the room, 14 for lights and 3 way

12 gauge to the room, 14 for lights and 3 way

You really need to read and study the NEC code book on wiring. When I started in the bussiness 35 years ago I highlighted important rules with yellow for quick reference. I still do and always carry my code book in the truck and keep one at home at my desk.
I-Wire knows the code better than anyone I have every seen and the reason he does is because he spends a lot of time in it. WE don't mind answering questions but you really need to study for yourself.
The electrical trade is a good one but you will be only as good as you prepare yourself. I have seen in sum code classes when we held up our books some electricians have old code books and never picked up a new one since they started. Always stay up to date and study the parts of the code that you are going to work on that day is a good way to start.
Didn't mean to go on so long but this is how I have done and continue to do. I think none of us mind helping or answering questions as long as you do some of the work yourself. Good Luck and welcome to the form and please don't take this post wrong. Just trying to help you along. Semper Fi. Buddy
 

M. D.

Senior Member
Here is a good expaination

Necdigest ?, February 2007
Compiled by Jeff Sargent and the NFPA Electrical Engineering Team

Q. Can I use 14-2 wire for the switch leg of a light fixture where the branch circuit is protected by a 20-amp circuit breaker? If this is against Code, why can I use 15-amp switches and receptacles on 20-ampere circuits?

A. The conductors from a switch location to the lighting outlet it controls are considered branch circuit conductors, not tap conductors connected to branch circuit conductors. These conductors are subject to the general overcurrent protection requirements of Section 210.20(B), which points to Section 240.4 for the specific overcurrent protection requirement. Section 240.4(D) specifies that 14 AWG copper conductors are to be protected by an overcurrent protective device with a rating or setting no higher than 15 amperes. And Table 210.24, which summarizes the requirements for branch circuits with two or more outlets or receptacles, specifies that the minimum conductor size for a 20-ampere-rated branch circuit is 12 AWG
Section 210.21(B)(3) permits a 15-ampere receptacle to be connected to a 20-ampere rated branch circuit. The terminals of feed-through type receptacles rated 15 amperes are tested for the heating that will result from the full load of a 20-ampere branch circuit. In addition, the attachment caps of cord-and-plug appliances are configured based on the appliance load. If the appliance is rated greater than 15 amperes, its cord cap will not be compatible with the configuration of a 15-ampere receptacle.
Snap switches installed on branch circuits are subject to the load requirements specified in Section 404.14. For AC general-use snap switches controlling resistive or inductive lighting loads, the minimum rating may not be less than the load it supplies. In other words, a 15-ampere switch installed on a 20-ampere circuit may supply a load of 15 amperes. For switches controlling lighting outlets supplied by 15- and 20-ampere branch circuits, it is the load controlled by the switch, not the rating of the branch circuit, that determines the switch?s minimum ampere rating.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
This is why we need inspectors.Short cuts and poor wiring habits are stoped fast cause they get caught.While 14-2 and 14-3 would work it is not safe or legal.Just where are you located and do they even license the contractors ?
 

dcspector

Senior Member
Location
Burke, Virginia
Jim W in Tampa said:
This is why we need inspectors.Short cuts and poor wiring habits are stoped fast cause they get caught.While 14-2 and 14-3 would work it is not safe or legal.Just where are you located and do they even license the contractors ?

I am very curious as well. Funwiring....Interesting handle btw. It sounds as if whoever is doing this type of work is having fun.....at someones expense or well being.
 

kbsparky

Senior Member
Location
Delmarva, USA
Jim W in Tampa said:
This is why we need inspectors.Short cuts and poor wiring habits are stoped fast cause they get caught.While 14-2 and 14-3 would work it is not safe or legal.Just where are you located and do they even license the contractors ?
Many areas of states like Pennsylvania and New York do not license electricians. I'm sure there are others as well.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
andinator said:
I disagree that It would be unsafe. It would not be legal.

What is unsafe is that unknown loads could be added.That switch might easily be removed and wirenuted and the wires at the fixtures box could be feeding almost anything.Electricians that would do this kind of work need to be fined and hopefully they take some courses in wiring.
 

iwire

Moderator
Staff member
Location
Massachusetts
Jim W in Tampa said:
Bob it is not about ampacity of #14 it is about #14 can not be fused/breakered at more than 15 amps.Its rated at 20 but fuse is 15

Jim, as it's rated for 20 amps installing it on a 20 amp breaker is not unsafe it is just an NEC violation.

The NEC allows me to supply a motor load of 20 amps with 14/2 AWG, the breaker might be a 50.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
iwire said:
Jim, as it's rated for 20 amps installing it on a 20 amp breaker is not unsafe it is just an NEC violation.

The NEC allows me to supply a motor load of 20 amps with 14/2 AWG, the breaker might be a 50.

Bob,the motor has internal overload protection.And if 20 amps is safe on branch circuits of #14 then why did they make the rule to use a 15 ?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Jim W in Tampa said:
And if 20 amps is safe on branch circuits of #14 then why did they make the rule to use a 15 ?


That's a good question, I could guess at an answer. Keeping #14 at 15 amps insures that Joe DYI'er has some fudge room for his violations. Before you ask, I have absolutely no documentation to prove this.:rolleyes:
 

Brady Electric

Senior Member
Location
Asheville, N. C.
12 guage to the room 14 for lights and 3 way

12 guage to the room 14 for lights and 3 way

I-Wire if I ever need an attorney in electrical will you bring your code book and defend me?
All good answers you have given.
Hope Fun wiring is getting something out of this and helps make electrical work safer where he works.
Any job I do that I don't need inspections on I still do it as the NEC Code says. My point to Fun wiring is the correct habits you learn now will follow you all your life. No matter who is doing wiring there seems to not know what they are doing and this forum will give you the straight scoop. Don't learn from electrician's that don't know what they are doing.
Semper Fi.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
I had a fire job that was simply #12 romex on 30 amp fuse.If that wire was safe at 25 amps then why did it catch fire from simply going over by 5 amps ? I think nec has included a safety factor to make up for things like a 20 amp breaker that might not trip at 20 but perhaps a few amps over.#14 on a 20 simply is not safe or legal
 

Funwiring

Member
Ok, wow, posted this morning and bingo, lots of comments. First, I did read the code thoroughly about 10 years ago, have the highlighted copy in the truck I work out of when wiring. Good idea. I just got a current copy and will bone up on changes since my last read. I live in Northwest Ohio. No inspection, no license required for wiring. It's nuts the things I see vs code here. Your feedback is appreciated. "Funwiring" is just that. My day job is working in an office and with people all day. For me, it's "fun" when I get out of the office and do some "wiring"... hands on stuff. Thanks for your replies.
 

Energize

Senior Member
Location
Milky Way Galaxy
Funwiring said:
Ok, wow, posted this morning and bingo, lots of comments. First, I did read the code thoroughly about 10 years ago, have the highlighted copy in the truck I work out of when wiring. Good idea. I just got a current copy and will bone up on changes since my last read. I live in Northwest Ohio. No inspection, no license required for wiring. It's nuts the things I see vs code here. Your feedback is appreciated. "Funwiring" is just that. My day job is working in an office and with people all day. For me, it's "fun" when I get out of the office and do some "wiring"... hands on stuff. Thanks for your replies.

Wow - that's a lot of reading in one session!:)
 

peter d

Senior Member
Location
New England
I'm just curious what you guys would do if you encountered this kind of installation. Would you change the breaker to a 15 (assuming it's a 20) or just look past it?
 
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