12ga vs 14ga wire?

My older home was originally wired exclusively with 12 ga BX into a fuse panel.
The fuse panel was replaced back in the '60's with a relocated breaker panel. The old fuse panel was used as a pass-through splice box. This work was done by a licensed electrician.
I've added a few circuits to the new panel with 12 ga Romex just to stay with the 12 ga convention.
Now. I want to re-wire the basement with additional lighting and utility outlets.
The Question....
Should I remain consistant with 12 ga/20 amp circuits all around...or...should I use 14ga/15 amp wiring for lighting?
I realize, the load is the real determining factor for 12 vs 14 ga, but instead of buying two different rolls of cable it would be easier just to standardize on 12 ga (or 14ga). The difference in price is nominal.
Yeah, I know if you are an electrician, the pennies add up to a little more profit on a job using 14 ga (where adequate), but what would an electrician do in his OWN home?
Or...
Is it customary to use 14 ga for lighting and 12 ga for utility circuits...or 14 ga all around -and only use 12 ga where REALLY necessary?
I realize there might be alot of philosophizing here...but I'd love to hear it.
Many thanks!

 

I really doubt that there will be much argument on what I am about to say. We'll see.

The minimum safety standards in wiring design is the NEC. NOtice that I said minimum safety standards. This should be a key point in your thought process when you make a decision on wiring design. All inspectors love to see more than the minimum, so do all those that reply in this forum and I have never spoke for all those that reply in this forum before.

I once had a life long freind that was a builder and had been a builder since before I went in business. He was losing jobs due to the new fangled idea of production housing. See he was a true custom builder and never skimped on products produced by his subs or his own work. He produced the best he and all his subs knew in quality for his customers. Problem was he was losing jobs left and right to production housing bulders who was building for much less. The customer saw the dollars accurately but only saw the cosmetics and not the true quality of the house. Problem is normally the woman of the household decides on this certain house because the counter faced the TV or the Laundry was in the dining room or the bathroom fixtures were gold colored.

After a while of this eating at that builder he called a meeting of all his subs and suppliers. He wanted to build a speck house that could beat the production builder's prices. He wanted all the bells and whistles but minimum code standards only on this speck house. We did just that. I wired the 12 awg only in the kitchen, landry, dining, bath where the NEC said that was minimum and wire 14 awg throughout the rest of the house as the code then and now says is minimum using 15 amp breakers.

This house looked as good as any he had built. The builder sold the house. The wife of the new owner loved to watch TV in the bedroom while she ironed her clothes. The bathroom light dimmed every time the iron came on. Complaints and accusations of rip off was abundunt and I took the beating.

I reminded the builder that he wanted minimum only on his wiring design to cut cost. He never challeged me from that reminder. I never wired a house for that builder again. While I wired for the builder freind of mine for 25 years that low cost wiring that he ordered set it that he hired another electrical contractor with his belief that I should never have let him talk me into wiring his spec house at minimum.

To have solved the dimming problem would have been easy. Run a dedicated circuit from the main panel in 12 awg for that iron being used on a general use outlet instead of in the landry on the laundry circuit designed for it. Guess the wife never read the Code book to understand whe was supposed to do her ironing in the laundry. Boy go figure!

Think you get the point. Minimum is not better. Minimum in that spec bedroom was safe but cost me a builder and a blemish on my reputation.

By the way the builder is still a freind and we go fishing now and again in Canada. He never had me wire another home though.

HOpe you get the moral of this story.

Wg

 

Interesting story Wg.

Your plan to use all 12-gauge wire is excellent in my opinion. However, the following are oft-cited reasons for using 14-gauge:

• It's cheaper.
• It's easier to run.
• It allows backstabbing.
• It avoids box fill problems in some boxes.

Only the last reason has anything at all that I would be interested in. However, if you buy the 22.5 cubic inch boxes and plan the wiring well, you won't have any box fill problems anyway.

It's a separate issue as to whether you want to put 15-amp or 20-amp breakers on that 12-gauge wire. I'd go with 20-amp breakers myself, but I can understand the argument for 15-amp breakers (marginally improved safety). If it makes you feel better, use the 15-amp breakers with the knowledge you can always swap them out for 20-amp breakers later should it become a problem.

 

I hope no one minds me throwing my 2 cents in here. You guys get no argument from me. I dont wire homes for a living so usually cost isnt really a factor most of the time. I wire one a while back for a friend though and material wasnt a factor but what I usually do is try to run the lighting seperate from any recepts and never load them heavy enough to make a difference. I break them up for convenience and ease of figuring out what goes where later. I like 14 in the ceiling,,, its just easier and quicker working overhead and pulling thru holes. I always put recepts on 12 and since it isnt connected to the lights we never get bounce in them. My own place is a little different and actually have a lot of recepts on their own breaker in places,, but it has conditions that might not come up in average residence. I can modify it at anytime and put new stuff when and where i need it. For example I use an electric heater for little bumps and add a pipe and a circuit just for that. I never have to pay attention to whats running or where as its almost impossible for me to actually overload here. When you are doing your own you have a little advantage and can add some items in you know you are going to have. I get a kick out of an electrician bud of mine. Has a bunch of vcrs, tv, all that junk and then some plugged in to one duplex. Power strips and countless 3 way adapters,, must be 30 things plugged in there. I mention that once and he said,,, yea I was curious so he put amp probe on and said he had average of 3 or 4 A and a high of 6. It was about 20 ft from the panel so its not how much is hooked on but what you use at any given time.. Just some jabber from someone that finish work at 1 Am,, ha

 

I cant believe people are still using the backstabs. I would never use them for anything. Have you not been on enough service calls where a ground has come off of the backstab and half of the circuit goes out. I think this will be added to the NEC soon. They are nothing but problems. The NEC has already mandated splices behind the recpt when you have feed-throughs. Now, if wired properly, it will be just one recpt that goes out when the backstabs fail. As for the wire size, I wire all lights in 14 and all recpt( no matter where they are) on 12.

 

If you are using less than 250' of wire total is is CHEAPER to use all 12 ga.

A 250' roll of 12 is cheaper than a 50' roll of 12 plus a 100' roll of 14.

Wire gets very expensive per foot when bought in rolls less than 250'

Click on the link to see what I mean about cost http://www.homedepot.com/prel80/HDUS...00009260&DRC=4

 

Is that when you push the wire in those little holes on the back of the receptacle?

Just wondering.

 

Yes

 

I think the last house I did (dont do many) I use 2-1000' rolls of 12 and a thousand roll of 14 and maybe a bit more than 250' roll of 14/3,,, avg house I guess. Does that sound right? I like thousand ft rolls better than 250. take a pipe and some 2 hole straps and put between studs and unroll. Way better than letting 250's uncoil,,, nice and straight. I know this is not really related but just food for thought for folks starting projects. regcab mention that and i saw a woman at the store the other day that bought wire by the foot,,, would have made way more sense to get a roll.

 

bwetzel, you said;

The NEC has already mandated splices behind the recpt when you have feed-throughs.

I am curious what Code refererance number is this mandate of pigtails when you have feed through. New one on me.

Curious

Wg

 

I will look it up and get back with you. It is in there. I has been in there for awhile now.

 

bwetzel, I suspect you will find it says MULTIWIRE not multioutlet. Look up your code and see if that word is there in the sentence then look in art 100 for definition of multiwire. If I am right you made the same mistake I made for years.

curious

Wg

 

It's in there I remember reading McGrall Hills interpetation of why which was because of Electrician's habit of changing recp out hot therebuy causing an open neutral when the wires are removed from the screws of an outlet when that outlet is part of a multiwire circuit. I'd look in Section 210..

 

I'm sure 1000' rolls are even cheaper per ft, but I feel HD and Lowes just rape ya when you buy less than 250'
As a contractor 1000' rolls are the only way to go, but the average HO will never need that much wire

 

Mike134, are you aware that there is no neutral conductor serving a 120 volt receptacle in a normal 120 volt multioutlet branch circuits.

Only multiwire branch circuits using 240 volt with a shared neutral splitting to two 120 volt circuits will have neutral conductor in a multioutlet branch circuit. Only the cable from the panel to the point where the 240 volts split to 120 volts will there be a neutral. All recepatcles on the load side of that 240 volt to 120 volt split will only have white grounded legs but no neutals.

The pigtailing of a receptcle is only required in the box where the 240 volts split into two 120 volt circuits. All other receptacles served with a 120 volt line does not have to be with a pigtail but can be fed through the receptacle becuase again there is no neutral conductor connected to a 120 volt receptacle.

I suspect the rule you guys are talking about is found in 300.13.B but it only concerns multiwire circuits serving the same device as a split receptacle having two 120 volt circuits to one receptacle and the like.

A branch circuit having only one 120 volt single breaker does not have a neutral conductor but instead has a grounded leg as a white wire only.

Hope this helps

Wg

 

Actually WG a national recognized authority on electricail codes and installations Joseph McPartland and McGraw-Hill publishers uses the term neutral quite often thoughout their text to add clarity to describing the grounded conductor. Also Manufacturs use the word to describe which terminal the ungrounded conductor is to be placed. I've always found that any electricain that uses the screws of an outlet to make his splice is a butcher that I wouldn't allow on my Jobs to wire a dog house. I releaze your pet peave is calling any white wire connected to a neutral bar a neutral but that's the way it's described by the electricail industry.

Mike

 

Also Manufacturs use the word to describe which terminal the ungrounded conductor




should have read grounded conductor

 

WG,
you need to explain what you are talking about here.

Mike134, are you aware that there is no neutral conductor serving a 120 volt receptacle in a normal 120 volt multioutlet branch circuits.

Only multiwire branch circuits using 240 volt with a shared neutral splitting to two 120 volt circuits will have neutral conductor in a multioutlet branch circuit. Only the cable from the panel to the point where the 240 volts split to 120 volts will there be a neutral. All recepatcles on the load side of that 240 volt to 120 volt split will only have white grounded legs but no neutals.

The pigtailing of a receptcle is only required in the box where the 240 volts split into two 120 volt circuits. All other receptacles served with a 120 volt line does not have to be with a pigtail but can be fed through the receptacle becuase again there is no neutral conductor connected to a 120 volt receptacle.

You dont think that the "white grounded leg" is not a current carrying conductor? Lets say you have a 12-3 feeding a wiremold strip where it is split up into 2 circuits. every other recpt is a circuit,while the "white grounding wire" is backstabbed into each recpt. You find the recpt that you want to replace and you shut the circuit off. But, You leave a clock or radio plugged into the other circuit that is sharring the neutral. This is going to hurt a little bit when you disconnect the two white wires.
I left my code book on the job, but I will look monday and find this. If in fact I am wrong and I have misread it like you say, I believe it should be cleared up and this should be added. I just think it is poor workmanship not to pigtail all recpt. That is just my opinion.

 

I have never said a grounded leg is not a current carrying conductor. I have said you can not have a neutral on a device that only has one ungrounded conductor connected to that device. That device does not have a white neutral but does have a white grounded leg that is a current carrying conductor. That grounded leg can not carry only an unbalanced load of two ungrounded conductors it must carry the full load of that one ungrounded conductor because there is no second ungrounded conductor of an opposite phase connected to that certain device.

A receptacle is a single device though may be a duplex device. Unless that receptacle device is a 220 volt split receptacle device with the top half fed by one hot conductor and the bottom half fed by a second hot conductor not of the same phase then you do not have a neutral serving that receptacle.

If that device only has one hot conductor serving it then that device can not have a neutral conductor meeting the definition of a neutral that carries the unbalanced load of two hot conductors of opposite phases.

A neutral carries the unbalanced load of two hot conductors. A normal 120 volt receptacle has only one hot conductor therefore there is no unbalanced load between two hot conductors because there is no second hot conductor in that circuit connected to that device.

Try the following link that may help

http://www.homewiringandmore.com/hom...ermground.html

Hope this helps

Wg

 

It's great the way you all can get off of a subject!
There are many opinions of what size wire you should run. There is advantages and disadvantages as far as technique. You are correct the load is the real determining factor. But lets not look at opinions and techniques, and look at facts.
Larger wire will indeed cost more when you go to buy it.
There are different techniques to install 14g. or 12g.
Over all cost will be cheaper to run a larger wire size in the long run. Beit 12g or even 10g.
Facts:

14g. Wire has a resistance of (3.07 ohms per Kft)
12g. Wire has a resistance of (1.93 ohms per Kft)
10g. Wire has a resistance of (1.21 ohms per Kft)
Knowing this. Lets diagnose a typical 50' circuit that has a load of 12Amps (Typical vacuum load).
50' 14g. Wire (ohms = 0.1535)
50' 12g. Wire (ohms = 0.0965)
50' 10g. Wire (ohms = 0.0605)

That 12-amp load will change in watts (true power) depending on the wire size you select.
(Isq.X R)
50' 14g. 12 amp load = 22.104watts
50' 12g. 12 amp load = 13.896watts
50' 10g. 12 amp load = 8.712 watts


Watts is what your Utility Company bills you on. So as you can see it can be cheaper to run a larger wire. Determine a wire size. And if you need a technique any of these moderators would be glad to help you.

 

WG wrote,
I have never said a grounded leg is not a current carrying conductor. I have said you can not have a neutral on a device that only has one ungrounded conductor connected to that device. That device does not have a white neutral but does have a white grounded leg that is a current carrying conductor. That grounded leg can not carry only an unbalanced load of two ungrounded conductors it must carry the full load of that one ungrounded conductor because there is no second ungrounded conductor of an opposite phase connected to that certain device.

A receptacle is a single device though may be a duplex device. Unless that receptacle device is a 220 volt split receptacle device with the top half fed by one hot conductor and the bottom half fed by a second hot conductor not of the same phase then you do not have a neutral serving that receptacle.

If that device only has one hot conductor serving it then that device can not have a neutral conductor meeting the definition of a neutral that carries the unbalanced load of two hot conductors of opposite phases.

A neutral carries the unbalanced load of two hot conductors. A normal 120 volt receptacle has only one hot conductor therefore there is no unbalanced load between two hot conductors because there is no second hot conductor in that circuit connected to that device.

I see what you are saying now. I (as well as most electricians) use the term nuetral to often. I know the NEC is trying to get away from using this term when talking about 120v circuits. I guess I am just use to everybody using that word. After all, when you say nuetral, you know that you are talking about the grounded side of the circuit What you are saying is correct, I was just not thinking along the same line.

 

I often use the term neutral when trying to explain something who is also using the term neutral but if I tried to explain the difference they would become more confused. I believe this is why the term neutral is often used as slang but not exact true term. There are occasions when this slang use of the word neutral invites a dangerous mistake and often it happens in a house where people want to connect all the white wires in a certain box together under one wire nut but that box contains more than one circuit.

Another time using the word neutral too loosely and can invite trouble is in the occasion that a person will run two hot wires of hte same phase and not be aware that the two wires add to the load of the white grounded leg because the two like hot wires can not counter each other but in reality adds to the load of hte white instead of carrying the unbalanced load of to unlike hot wires.

I just discovered over years of teaching that to maintain the "AKA NEUTRAL" for a grounded leg brought to the students mind on a regular basis that the is a marke and sometimes hazardous difference the different white wires in a wiring design. Seemed to help in my teachings. Started using that aka in my replies in this forum. Once in a while we catch a person that didn't know the difference. Those few times that some one caught on the difference and the added safety in his or her wiring style was worth the effort in my replies.

Gets confusing quite often but often times the confusion turns into a light at the end of the tunnel in the way a person thought of a white wire.

Sorry if I caused confusion but maybe someone caught on to the difference in this side bar discussion.

Aphares is right we often stray from the original poster's questions but I believe that the side bars most often appear after the poster had received their answers.

If we are still talking about electricity I guess we are still on the subject. Seems like the side bar tends to sort through some confusion now and again to the positive for one or two reading the side bars.

Wg

 

Aphares,,, Are you saying it takes twice the current to run that on a 14 as a 10,, so I should throw out those 16 cords for over 5 amps and anywhere I run a skillsaw I should have no 10? Ok,, I run my paint booth fan 3 hrs a month,,, 1 hp,, its running on 30 ft of 12,,, how long is it going to take to pay to change the wire? I should change it to 220 maybe too.

 

Better question yet,,, at 12 a load on number 12 and 12 a load on 10,, what is the cost difference to operate per 100 hrs? You could figure 10 cents a kwh to make it easier. This may pay for ac units or something that runs lots hrs.

 

Although aphares is correct in saying that larger wire results in less power consumed by the wire, it is not correct to extrapolate that fact to say that you will save money with the larger wire. It may or may not be true, depending on what loads you use.

For example, a 60-watt lamp running on a circuit wired with #14 will actually cost less than the same lamp on a circuit wired with #10 -- that is, the heavier wire results in increased cost rather than decreased cost. This is due to the fact that the smaller wire imposes more resistance and thus less current. Of course, the light bulb will burn more dimly on the #14, since more power is consumed in the wire and less in the bulb.

Consider another example. If you use a hair dryer on a circuit with #14 wire, it will cost less per minute than the same hair dryer on a circuit with #10 wire. However, it will cost more to get your hair dry, since the hair dryer will produce less heat and it will take longer to dry your hair.

This is all a theoretical discussion. I am not advocating smaller wire. I'm just saying that you need to analyze the entire system to see what's happening.

On the side note: The reason I use the word "neutral" incorrectly on purpose is that there is too much danger of someone misinterpreting if I would use the more correct term "grounded conductor." There's just too big of a chance that someone might think I meant "grounding conductor". To avoid this potentially dangerous misunderstanding, I use the word "neutral" even when I know that's not what I really mean.

 

I usually try to stay within 2% voltage drop on most things,,, now you guys are going to give me something else to be paranoid about,, ha,, Now I will lose sleep at night trying to calculate how much it cost to run the vacuum for the rest of my life.

 

John,,, thats what I thought in some cases,,, like motor starting,, actually less current would be used due to wire resistance. Ok,,, I understand the hair dryer philosophy,, how would it apply to ac's and fans?

 

A vacuum cleaner (or anything with a motor) will run more cheaply per minute on a circuit wired with #14, but likely won't work as well or last as long, since it won't be getting as much voltage. So if your floor isn't really very dirty, plug your vacuum into a circuit wired with #14. But if your floor is very dirty, then you want the circuit wired with #10. Pretty silly discussion, huh? Don't answer that!

 

I will comprimise and go with 12 then,,hehe,,,, now,,, does one really save money stocking up on crimp connectors today 130$ worth.

 

Kelvin's Law:
" The most economical area of conductor is that for which the annual cost of energy wasted is equel to the interest on that portion of a capital outlaw which can be considered proportional to the weight of copper used"
Cmil = 55,867 x I x SqRt (c1 / c2 x A)
Where Cmil = area, in circular mils, of the most economical conductor:
I = the mean annual current:
c1 = cost of energy per kilowatthour:
c2 = cost of copper, in dollars, per pound installed:
A = annual charge, in percentage,

If we take 12ohms as the resistnce of a circular milfoot of commercial copper wire at 50'C, the power loss in any conductor can then be found thus:

P = 12 x Isq x L / cmil
Where P = power loss in the condutor in watts
I = the mean current in amperes in the condutor
L = length of the conductor in feet,
Cmil = area of the conductor in circular mils.

The cost of energy loss can be computed from the following formula:

Cost of energy per year in dollars =
N x P x 8760 x R / 1000 x 100

N = number of conductors
P = power loss in one conuctor
R= cost of electric energy in cents per kilowatthour
8760 is the number of hours in a year
1000 is the factor to change watts to kilowatts
100 changes cents to dollars.

Thus:
cost of energy lost per 500 hours of operation with cost of electrical energy at 2 cents per kilowatthour.

wire size length of conductor load/amps
6a 10a 15a 20a
14g. 50' $0.10 0.26 0.60
100' $0.19 0.52 1.20
200' $0.38 1.04 2.40
300' $0.57 1.06 3.60
12g. 50' $0.06 0.16 0.36 .064
100' $0.12 0.32 0.72 1.28
200' $0.24 0.64 1.44 2.56
300' $0.36 0.96 2.16 3.84
10g. 50' $0.04 0.10 0.22 0.40
100' $0.08 0.20 0.45 0.80
200' $0.16 0.40 0.90 1.60
300' $0.24 0.60 1.35 2.40
( edit, this table is not appearing as i have it drawn, Sorry)


Cost of energy lost per year in dollars = H x R x K / 500 x 2

H = hours of operation of circuit per year
R = cost of electrical energy in cents per kilowatthours
K = is the dollars as obtained from the table above

 

I don't know about you, But I think that is enough. You guys are getting way off track on what this forum is about. Do you think you are helping any homeowner out by posting this stuff???

 

Thanks for the figures aphares,,, cool,,, I can save almost 50 cents a year if I change a couple of wires out. I will be able to sleep at night knowing I am doing my share for energy conservation.

 

Boy is this thread getting interesting!

I suspect if we looked at what John and Aphares is saying they are essentially saying the same thing. Bypassing the technical language and saying it in terms normal poeple can understand try the following;

I believe that aphares is saying that the larger the wire to a certain load the more efficient that product will run. To a point I agree with his statement to a limit of adversity.

I believe John is saying that what aphares was trying to portray is mechanically correct yet again to a point of adversity. I belive what John is saying is what I believe also.

The wire size does affect effeciency of cost but only to a point of logic adjustment. Bigger is better to a limited point of no monetary return for investment.

Example resistance heat when served more power will eat more power.

Motors performing work when served more power will work more easily to do that work.

Increasing size of conductor is a good thing until you have increased that wire size beyond what that product needs to do its desired design of production. Then the extra cost of the the wire larger than that product needs to perfrom then the larger wire becomes non cost effective.

Sounds a lot like John is saying that aphares is right but only to a logical level of increasing wire size to fit the need required to produce effeciently and cost effectively.

Boy my head is spinning,

Wg

 

Figure how much wire you need total and see if it's cheaper to use one big roll of 12 or 2 smaller rolls of 12 and 14

Dang engineers !!!!

 

54,,, Hey I always wondered how much difference it would make to efficiency so its an interesting conversation. I think following the 2% Voltage drop would come in pretty close,, especially for things that have very much run time. They call this mental masturbation I think.

 

Bigger wire helps hard starting motors such as compressors todraw the amperage needed for the "kick start"

Ever try to run a window unit through an extension cord ??