# 14ga switch leg on a 12ga circuit



## mdale (Aug 30, 2014)

I have a 14ga switch leg that controls the last outlet in a circuit that is ran with 12ga. All the wiring looks original to the house (built in the 60's) is this normal/allowed?


----------



## nealtw (Aug 30, 2014)

I think it is if the breaker is 15 amp and welcome to the site.


----------



## slownsteady (Aug 30, 2014)

If it is just the switch, I might let it go, but I'm sure it's not code.


----------



## mdale (Aug 30, 2014)

Thx, it's on a 20 amp breaker and I'm getting ready to add a ceiling fan, so I think I'm go to remove the 14ga and pull in a 12-2 from the last outlet to the fan and then 12-3 for the switch leg. First thought was just to make the switch leg as power to new fan and then run new 3conductor to the switch, but then found out about the 12/14ga mix.


----------



## JoeD (Aug 31, 2014)

It is not code and should be corrected to #12 wire. #14 is not permitted on a 20 amp circuit except in some very specific cases involving motors. This is not one of them.
You make it correct by changing to a 15 amp breaker.


----------



## WyrTwister (Sep 6, 2014)

Depending on where you are .  It depends on the AHJ .  It is often done on Romex / residential work , here .

     I am not saying it is code legal .  I am just saying that is the way it is traditionally done here .  Wright or wrong .

     It may or may not be , where you live .

God bless
Wyr


----------



## speedy petey (Sep 6, 2014)

WyrTwister said:


> Depending on where you are .  It depends on the AHJ .  It is often done on Romex / residential work , here .
> 
> I am not saying it is code legal .  I am just saying that is the way it is traditionally done here .  Wright or wrong .
> 
> ...


Saying it is allowed where you are does not help. It IS wrong, PERIOD, and to suggest otherwise is irresponsible.

If it is traditionally done where you are all that says is that you have hack electricians and even more hack inspectors.


----------



## WyrTwister (Sep 6, 2014)

speedy petey said:


> Saying it is allowed where you are does not help. It IS wrong, PERIOD, and to suggest otherwise is irresponsible.
> 
> If it is traditionally done where you are all that says is that you have hack electricians and even more hack inspectors.



     Think about what you have said .

     The inspectors may or may not be hacks ?  I have / have had no control over that .

     That does not make the electricians hacks .  

     The code has always been / meant what the local AHJ said it meant .  This means wiring methods / standards more stringent or less stringent  than the current NEC .  Or , in some case a mix of of both , on different topics .

     That is the way it is , at least in my locality .  As I previously said , your locality may / probably does vary .

     As strong as you came on , one would think this issue would result in homes burning down , by the thousands , maybe the tens of thousands , in my locality .  That is not happening .

     I have seen a lot of good wiring and some bad wiring in my time .  Using # 14 copper for switch legs is in no way close to the top of the list of " bad " wiring practices .  If it is even on the list .

     How many houses have you seen that have " back stabbed / back wired " devices .  How many of those have you seen that went bad ?  I gave seen my share .  I did a service call around a month ago that a " back stabbed " plug has a neutral over heat & burn up the receptacle .  It came out of the device .

     This was not caused by the wire size .  It was caused bu the back stabbed plug / wiring method .  But it could have caused a fire .

     Yet it was SOP at the time .  And a BUNCH of them are still in use .  

     If I was going to loose any sleep over bad wiring practices , back stabbed recepticals would be one of the issues .  Not # 14 copper wire on switch legs .

     Back away from the situation ( a little ways ) and gain some perspective .  

     Best of luck to you .  Have a fine weekend .   

God bless
Wyr


----------



## speedy petey (Sep 6, 2014)

WyrTwister said:


> Think about what you have said .
> 
> The inspectors may or may not be hacks ?  I have / have had no control over that .
> 
> ...


Sorry, but I disagree. 

Codes DO NOT mean what inspectors say they mean. Codes mean what they mean. Inspectors are there for enforcement and sometimes interpretation, and NO, they CANNOT allow less than code minimum at their whim or discretion. Same as they cannot require more than code allows. 

I do agree with you, this is not something that is going to burn a house down, but in this case there is little left to interpretation. Code is code.
Put #14 lighting switch legs on a 20A circuit as a professional and yes, that makes you a hack.


----------



## WyrTwister (Sep 8, 2014)

speedy petey said:


> Sorry, but I disagree.
> 
> Codes DO NOT mean what inspectors say they mean. Codes mean what they mean. Inspectors are there for enforcement and sometimes interpretation, and NO, they CANNOT allow less than code minimum at their whim or discretion. Same as they cannot require more than code allows.
> 
> ...




     Have a nice day .     

God bless
Wyr


----------



## speedy petey (Sep 8, 2014)

WyrTwister said:


> Have a nice day .
> 
> God bless
> Wyr


OK?


----------



## nealtw (Sep 8, 2014)

My turn, not good enough to talk just about code. What can happen, is the question.

The 14 wire can be overloaded and start a fire before the 20 amp breaker kicks off and for that reason it should not be done and home owners should not consider it.


----------



## Fireguy5674 (Sep 9, 2014)

OK I am going to play devils advocate here and ask a question I know will be controversial.  I do not have access to an NEC code book so I can't look at the code language, but I agree that a 20 amp circuit must be run in 12 Ga wire.  My question is, when you get to the end of a circuit run how is it possible to overload a 14 Ga wire either to a receptacle or a light if: a) the receptacle is a 15 amp rated plugin type and there is no other downstream load?  (A dead short will cause a trip no matter what size the wire.)  b) the load on the light circuit is 15 amps or less, a 15 amp rated switch is used and there is no other downstream load?  (No, I would not suggest this for more than a single fixture setup where multiple bulbs could be changed and cause an overload situation.)  I was a fireman for over thirty years and as many screwed up wiring jobs and fires caused by faulty electrical wiring as I saw, I do not believe I ever saw one caused by this situation.  Again I am not trying to cause a fight or pick who is right or wrong.  It is just a question as food for thought.

I think the worst I ever saw was a #12 run into a panel and tied directly to the 400 amp main fuses.  Surprise, we were there putting out a fire at -5 in January.


----------



## bud16415 (Sep 9, 2014)

Purely academic answer I would say in the case of a dead short you could instantaneously draw some huge current thru 14 ga wire and trip a breaker. Now in the case of a short that isn&#8217;t a dead short. Say the switch or light fixture malfunctioned and had some sort of arcing going on and the current draw was slow and something between 15 and 20 amp draw. The 14 gage wire would heat faster than a 12gage and that heat could cause insulation failure and fire.  

That would be my guess why code always matches the wire to the protection.


----------



## JoeD (Sep 9, 2014)

The simplest way to over load the #14 would to overlamp the fixture or fixtures.


----------



## slownsteady (Sep 9, 2014)

Well, there's always the chance that the next owner will decide to extend the circuit for whatever reason, and not have a code book handy. But I see that as a remote possibility with a switch leg if the wires are coded (marked) black.


----------



## nealtw (Sep 9, 2014)

slownsteady said:


> Well, there's always the chance that the next owner will decide to extend the circuit for whatever reason, and not have a code book handy. But I see that as a remote possibility with a switch leg if the wires are coded (marked) black.



All you need here is for someone to come later and wire in a switched outlet for a lamp and then plug in a heater and a few old xmas lights.

I don't agree with calling someone a hack, as pros we, most of us have been guilty of doing things because that's the why we have always done it. If the inspectors don't catch it or let it slide the bad habits continue. People come here to help where we can and from time to time we learn a few things along the way.

A new member coming to help is a good thing and sometimes a constructive discussion is needed, name calling is not in my book required.


----------



## Fireguy5674 (Sep 10, 2014)

Yes the things the uniformed do to electrical circuits is amazing.  As I said as a fireman I got to tear open things when there was a problem and see what had been done providing the building was still standing.

One neat trick I found in the house I live in now was fun.  If you opened a box you found newer type wire with a ground.  Later when I opened the wall I found the new wire extended about three feet and was then spliced into old wiring with a couple of wire nuts and no box. Found several of those. Another neat trick was the electric water heater.  Couldn't figure out why the water heater didn't supply adequate hot water.  In the process of rewiring some things I discovered that although the water heater was wired correctly it was attached to a 110 circuit breaker and only one element was working.

Sorry I am getting off topic.


----------



## bud16415 (Sep 10, 2014)

The bottom line is you would never want a wire to be the fuse in a circuit. Anytime the wire rating is less than the breaker rating that is a possibility. 14gage wire may be able to carry 20amps for some extended period of time, but wire like all things has a safety factor designed into its numbers. When you over power anything the safety factor diminishes rapidly as does the life expectancy. 

Code has to set a limit some place. Imagine if everything code handled had sliding scales based around all kinds of factors as inputs. Someone that knows what the reality is of their device can design in any safety factor they want. Many items are plugged into 20 amp protected outlets that have much finer wire than 12 gage. The code ends at the wall plate, but you can still have melt down and fire.


----------



## hornetd (Nov 21, 2014)

Fireguy5674 said:


> OK I am going to play devils advocate here and ask a question I know will be controversial.  I do not have access to an NEC code book so I can't look at the code language, but I agree that a 20 amp circuit must be run in 12 Ga wire.  My question is, when you get to the end of a circuit run how is it possible to overload a 14 Ga wire either to a receptacle or a light if: a) the receptacle is a 15 amp rated plugin type and there is no other downstream load?  (A dead short will cause a trip no matter what size the wire.)  b) the load on the light circuit is 15 amps or less, a 15 amp rated switch is used and there is no other downstream load?  (No, I would not suggest this for more than a single fixture setup where multiple bulbs could be changed and cause an overload situation.)  I was a fireman for over thirty years and as many screwed up wiring jobs and fires caused by faulty electrical wiring as I saw, I do not believe I ever saw one caused by this situation.  Again I am not trying to cause a fight or pick who is right or wrong.  It is just a question as food for thought.
> 
> I think the worst I ever saw was a #12 run into a panel and tied directly to the 400 amp main fuses.  Surprise, we were there putting out a fire at -5 in January.



Unless that last receptacle is of the less common single socket variety the likelihood of overload is built in.  Will the people shampooing your rugs or refinishing your floors give a second thought to plugging two fifteen ampere loads to that duplex receptacle?  If each of the things that they plug in has a National Electrical Manufacturers Association (NEMA) 5-15P plug end then it could require fifteen amperes during normal operation if it is designed for intermittent use.  If it is designed for continuous use it could draw up to Twelve amperes for three or more hours.  In either case the total load could readily exceed the actual current carrying ampacity of the conductors.  A twenty ampere breaker would put up with that overload for long enough to damage the insulation on the conductors and an arcing fault may result.  As you have undoubtedly found on many occasions arcing faults produce a lot of heat and they do not necessarily draw enough current to promptly open the breaker.   Once that insulation is damaged there is no telling what consequences will be forthcoming.  

--  
Tom


----------

