 FronkmanAn Apple a day keeps the doctor away
Premium Member
join:2003-06-23
Saint Louis, MO |
Fronkman
Premium Member
2012-Feb-13 3:50 pm
is 12/2 really necessary?i am about to embark on rewiring the first floor of my home via the basement. it is currently a mix of cloth NM and K&T. service and panel have already been upgraded to 200A (including a brand new NEC compliant grounding system).
i have done a ton of reading over the last few weeks as i plan this project and I have gotten mixed messages about appropriate wiring gauge. as i understand the generic NEC code, the majority of the 1st floor should be wired to 15A breakers with 14/2 (there will be no space heaters, no air-conditioners... just lamps with CFLs, Christmas trees, the occasional vacuum cleaner, TV and/or cell phone chargers).
obviously the half bath will need a separate 20A circuit with a GFCI wired with 12/2. the kitchen is it's own thing with at least two 20A circuits for appliances and the 240V circuit for the oven, etc.
in my reading i have come across a number of authors who strongly implore the reader to consider using 12/2 on the 15A circuits because they feel it is safer (won't get as hot under a max load) and because it allows you to upgrade to 20A breakers and receptacles in the future.
to me, the extra cost of the 12/2 (33% higher) as well as the decreased workability of the wire (since this is all old work with lots of pulling through walls) is not worth it. over the last ten years my electricity use has actually declined as my appliances, devices and lights get more power efficient. i do not envision any circumstance in which i would NEED to upgrade a receptacle in my living or dining room to 20A.
i am curious what everyone's opinion is in this situation. |
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 shdesignsPowered By Infinite Improbabilty Drive
Premium Member
join:2000-12-01
Stone Mountain, GA
ARRIS SB6121
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I'd never wire anything with 14/2 that has general purpose outlets.
With most vacuum cleaners bragging about amps rather than power, they are now power hogs. My current one brags about 12 amps and does not have much power. My old 2.3HP (probably peak) sears one would run circles around it and drew less power.
Most vacuum cleaners now are over 10 amps. Not much left on a 15A circuit.
14/2 can handle the current but you will see lights dim when they turn on and things like set top boxes, cable modems and other electronics may just reset themselves.
I also had a small laser printer with a 1000W fuser.
I'd rather have 12/2 and less drop with load. Even on 1 15A breaker, I'd prefer it.
I added 2 circuits in the basement with 12/2. Can run a small space heater and still run the vacuum or laser printer. Best thing is the lights don dim when the printer or heater fired up. |
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to Fronkman
You're talking about a $100 difference on a major project.
You'll have to buy massive amounts of 12/2 anyway. You could just buy in bulk and be done, may end up cheaper than smaller quantities of 12/2 and 14/2
Why not do things the best possible? How much extra effort would it be to pull 12/2 instead of 14/2? Sure I see no reason to run 12/2 for lights only, but if it were my house I'd run 12/2 for outlets without hesitation (maybe even 10/2 for long segments feeding multiple rooms. I have long runs and in one room the hair dryer brings the voltage close to 100V. |
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 Msradell
Premium Member
join:2008-12-25
Louisville, KY |
to Fronkman
I too wholeheartedly endorse the use of 12/2 on all general purpose receptacle circuits even if only attached to a 15 amp breaker. The wire itself certainly does cost more but it's still not that much more expensive in the long run and it certainly gives you a lot more flexibility in the long run.
The only place I never use #14 wire is for lighting circuits. |
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to Fronkman
I use 12/2 to do all my additional work in an old 1960's house on 15A circuits. It does cost more but if nothing else I feel safer knowing the wire won't burn and kill my family. Also resale value is better if you can say you've been *upgrading* the wiring rather then just expanding the wiring. |
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 guppy_fish
Premium Member
join:2003-12-09
Palm Harbor, FL |
to Fronkman
I have never in my life used 14/2, always 12/2. Just buy a 1000ft reel, the cost difference isn't even worth having to then explain to the inspector why your trying to save 100 bucks. |
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 EdrickI aspire to tell the story of a lifetime
Premium Member
join:2004-09-11
San Diego, CA |
to Fronkman
Uh, so what's the point of wiring the whole place in 12/2 yet only using 15A devices? Seems to me like you might as well wire the whole place with 20A breakers and receptacles too. |
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to Fronkman
Standard duplex outlets are 20a pass through devices, and they make 20amp GFCIs. You can have a 20amp breaker for modern panels for the same cost as a 15amp. If bulk wire cost isn't a big deal to you, I'd do the new circuits end - to - end and up it all to 20amp.
Notice the bold section, end - to -end. We are talking if you go this route, any circuit you upgrade will NOT be using any existing wire anywhere, unless you are 100% sure all devices and wiring are rated to be on a 20amp circuit. |
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to Fronkman
Go with 12/2. It isn't about what you need it for today, it is what you need it for tomorrow. Plan ahead... |
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 nunyaLXI 483
MVM
join:2000-12-23
O Fallon, MO ·Charter
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to Fronkman
Normally (in our neck of the woods), 14/2 (15A) is used for the general purpose and lighting circuits.
14/2 is just fine. Keep in mind that you'll wind up with more circuits. My "rule of thumb" is 10 receptacles on a 20A circuit, and 7 receptacles on a 15A circuit. I've done it this way "ever since". I don't like callbacks, and I don't get callbacks.
There is no set number in the code for residential. You could put 547 receptacles on a single circuit, and it would still be compliant.
12/2 is just a bit more difficult to work with. 14/2 is just right. So, there's also a time savings.
If I get a situation, such as a long string where it would be silly to run two circuits, I'll go ahead and run 12/2.
I have mostly 15A circuits in my own home, and I'm not the least bit concerned about it.
You'd better cross your t's and dot your i's though. Both the city and county are cracking down HARD on homeowners doing unpermitted work. All it takes is one nosy neighbor to make a phone call. |
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 alkizmo
join:2007-06-25
Pierrefonds, QC |
to Fronkman
I wouldn't worry about it. Just make sure you make the effort to make as many circuits as you can instead of sharing multiple rooms on the same circuit. Vacuums may use almost 15a but that is for a few minutes only. Worst come to worst and you'll trip the breaker. |
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 sk1939
Premium Member
join:2010-10-23
Frederick, MD
Ubiquiti UDM-Pro
Juniper SRX320
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to nunya
See, I have the opposite opinion. Having an older house with mostly 14 Gauge BX (some cloth, some not), I have to say that if you have a laser printer, vacuum cleaner, electric blanket, space heater, or corded power drill, you should go with a 20A 12/2 circuit. My experience is that should I run any of those, the lights dim and flicker significantly. Using my Shop Vac and drill in tandem recently caused the breaker to trip when the drill bound in a knot. |
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 Caddyroger
Premium Member
join:2001-06-11
To the west |
to Fronkman
When I had my house built in 1974 I did the electrical my myself. Installed 12/2 in all rooms. |
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The house I had built in 1984 had all 12-2 with the exception of the ceiling fixtures of which many had 3-way switches with 14-3 the rest had 14-2. |
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to Fronkman
said by Fronkman:i have come across a number of authors who strongly implore the reader to consider using 12/2 on the 15A circuits because they feel it is safer (won't get as hot under a max load) Sure, it will not get as hot. Might as well use 10 gauge. And if you want to feel safer, then you might as well use 8 gauge or even 6 gauge. But using 14 AWG on 15 amp circuits is as safe as it possibly needs to be. As far as safety goes - there is absolutely no reason to use 12 AWG on 15A circuits, unless you want to protect yourself against some jackass who could come in later, and illegally and dangerously change out the 15A over-current protection for 20A. And if you're going to do that; you might as well just use 20A breaker to begin with. (Wiring with 12AWG and not using 20A breaker is just asinine to begin with.) You can trust me, or nunya, or anyone else on this. You're not gaining any safety. Any author who strongly encourages using 12 AWG wire on a 15A circuit for this reason, is mistaken, and likely has little real professional experience. That being said, there are non-safety related pro's and con's to the use of both gauges. Being able to 'upgrade to 20A breakers in the future' is not one of them. It would be downright stupid to run the wiring using 20A now; buy 15A breakers now; and then pay again to buy 20A breakers later - when you could have put the 20A breakers in in the first place and saved money. I prefer 20A wire for receptacle circuits. You are less likely to discover later that you need more receptacle circuits because your existing ones are overloaded. I prefer 15A for residential lighting circuits, primarily because its easier to wire and I like to break my lighting circuits with more switching, dimming, etc. It seems to work out better. Of course, if I have more than 1440 volt-amps (watts) of lighting on a circuit, I will use a 20A circuit. In your case, I would recommend 20A circuits (wire and breakers) for the receptacles; especially if you were considering 12 AWG wire to begin with. Size the lighting circuits for their loads. |
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said by whizkid3:Sure, it will not get as hot. Might as well use 10 gauge. And if you want to feel safer, then you might as well use 8 gauge or even 6 gauge. But using 14 AWG on 15 amp circuits is as safe as it possibly needs to be. Not sure if your trolling but good job! After seeing a 15a rated a/c unit melt the insulation on 14/2 I'll stick with 12/2 on my 15a circuits. 14/2 is like you said....as safe as it needs to be which isn't that safe given all the possible uses for an outlet on 14/2. |
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alkizmo
join:2007-06-25
Pierrefonds, QC
1 recommendation |
said by Critsmcgee:Not sure if your trolling but good job! After seeing a 15a rated a/c unit melt the insulation on 14/2 I'll stick with 12/2 on my 15a circuits. 14/2 is like you said....as safe as it needs to be which isn't that safe given all the possible uses for an outlet on 14/2.
If something caused the insulation to melt on 14/2 on a 15A protected circuit, then you've got another problem that may also cause 12/2 insulation to melt... like a crappy A/C and/or breaker. |
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said by alkizmo:said by Critsmcgee:Not sure if your trolling but good job! If something caused the insulation to melt on 14/2 on a 15A protected circuit, then you've got another problem that may also cause 12/2 insulation to melt... like a crappy A/C and/or breaker. Not trolling. I understand intimately how heat dissipation in circuits and thermal-magnetic circuit breakers work; and how both are designed to prevent this situation in any size wire & circuit. Alkizmo has it exactly right. If you've seen this - then you missed the other, real problems with the wiring or circuit. |
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05451874 (banned)
join:2012-01-18
Worcester, MA |
to alkizmo
said by alkizmo:said by Critsmcgee:Not sure if your trolling but good job! After seeing a 15a rated a/c unit melt the insulation on 14/2 I'll stick with 12/2 on my 15a circuits. 14/2 is like you said....as safe as it needs to be which isn't that safe given all the possible uses for an outlet on 14/2.
If something caused the insulation to melt on 14/2 on a 15A protected circuit, then you've got another problem that may also cause 12/2 insulation to melt... like a crappy A/C and/or breaker. Possibly but then why didn't his 12/2 ALSO melt? If 14/2 melts and 12/2 doesn't let's apply some logic instead of non-sense. An a/c unit could function fine on a 15a circuit as required yet when the compressor kicks on it can draw more then 15a's under some conditions. One example is if the coil is a bit dirty that can cause it to draw more then normal. It should be cleaned but how do you know? You can have 14/2 if you want but knowing how appliances work in reality 12/2 is the only way to go to account for the extras that can and will happen in life. |
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to Critsmcgee
said by Critsmcgee: After seeing a 15a rated a/c unit melt the insulation on 14/2 I'll stick with 12/2 on my 15a circuits.
If you had this happen you had way more going on other than the circuit being 14/2. |
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to Critsmcgee
said by Critsmcgee:said by whizkid3:Sure, it will not get as hot. Might as well use 10 gauge. And if you want to feel safer, then you might as well use 8 gauge or even 6 gauge. But using 14 AWG on 15 amp circuits is as safe as it possibly needs to be. Not sure if your trolling but good job! After seeing a 15a rated a/c unit melt the insulation on 14/2 I'll stick with 12/2 on my 15a circuits. 14/2 is like you said....as safe as it needs to be which isn't that safe given all the possible uses for an outlet on 14/2. as the other guys said, you really have other problems going on, like a loose connection somewhere (ive seen 15 inches of insulation burned off a wire for a dryer due to this) which is somthing only an ACFI would have stopped, or you have a faulty breaker. Some breakers have issues with tripping (google zinsco and stablok) im at a loss as to why you would go to the added expense or running wiring rated for 20 amps yet not put the 20 amp devices. That is like building an expressway rated at 70 MPH and putting a 30 MPH speed limit, just to be safe. I have discussed with many professionals in the field due to my line of work and the general opinion is if the breaker and wire are matched ie 14 awg with a 15 amp breaker and the wiring fails there is a problem with either the way the circuit is wired (high resistance connections) or your overcurrent device is faulty. |
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05451874 (banned)
join:2012-01-18
Worcester, MA |
05451874 (banned)
Member
2012-Feb-14 8:54 am
said by telco_mtl:That is like building an expressway rated at 70 MPH and putting a 30 MPH speed limit, just to be safe. They do this in every state in the US. Bad analogy but welcome to DSLR. |
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49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL
1 recommendation |
to Jack_in_VA
said by Jack_in_VA:If you had this happen you had way more going on other than the circuit being 14/2.
More so when you consider the fact that 14 AWG copper can carry 20 amps until the cows come home without a problem. Wayne |
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 LazMan
Premium Member
join:2003-03-26
Beverly Hills, CA |
to nunya
said by nunya:Normally (in our neck of the woods), 14/2 (15A) is used for the general purpose and lighting circuits.
14/2 is just fine. Keep in mind that you'll wind up with more circuits. My "rule of thumb" is 10 receptacles on a 20A circuit, and 7 receptacles on a 15A circuit. I've done it this way "ever since". I don't like callbacks, and I don't get callbacks.
There is no set number in the code for residential. You could put 547 receptacles on a single circuit, and it would still be compliant.
Depends where you're at - you're in MO; OP's in MO - in this case, I'll defer to you...  Up here in Canada (Ontario, specifically) there are limits - 12 devices per circuit (device being a fixture or recepticle, switches don't count) - and 20A circuits cannot be used for lighting. To the OP - 14ga wire has been used for 15A circuits for years and years and years, and is fine; all things being equal. You're not going to hurt anything putting in 12ga - and it's not that much harder to work, really - but it's not going to buy you much, either - odds of having to change a 15a recepticle out for a 20a, without doing any other changes to the circuit, or isolating it out to a dedicated line for something, are pretty slim... There is slightly more voltage drop on a 14 ga conductor, and slightly higher ressistance - but neither of these things will be a concern in most residential situations. If you've got insulation burning off, wiring overheating, etc, as has been correctly pointed out, you've got bigger issues then 14ga vs 12ga copper... |
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FronkmanAn Apple a day keeps the doctor away
Premium Member
join:2003-06-23
Saint Louis, MO
1 edit |
Fronkman
Premium Member
2012-Feb-14 10:31 am
thanks to everyone for the replies.
i will clarify my question a little bit. the new panel in the house already has 15A breakers for the non-kitchen, non-bathroom circuits. i have no intention of buying any breakers.
the previous things i have read, along with what several people in this thread have stated is that: on a 15A circuit, with 15A receptacles is it preferable to use 12/2 for that circuit purely because 12/2 is "safer."
as far as cost is concerned, a 33% premium IS a lot. sure, in a job being done by a professional electrician the difference in cost is small because LABOR is the majority of the price anyway. however, *I* am the labor in this case and differences in materials cost is important. 12/2 is 33% more expensive and 20A devices are 500% more expensive. as I have already said, i won't be running air conditioners or space heaters on this circuit and the nearly the entire house is hardwood, the vacuum is only going to be on for a few minutes at a time.
so far i am unconvinced. does anyone really think that 5 years from now the NEC will require 12/2 on 15A circuits?
oh, and don't worry nunya appropriate permits will be pulled. |
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 DarkLogixTexan and Proud
Premium Member
join:2008-10-23
Baytown, TX |
to Fronkman
If it were me, and I'm not saying you should do what I would but.
I'd use 10/2 for all 15a circuts and 8/2 if it'll fit in the 20a outlets
basicly I'd find the largest wire size thet'll fit the outlet and use that
whats a hundred or 2 on a major project? |
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49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL |
49528867 (banned)
Member
2012-Feb-14 10:59 am
said by DarkLogix:I'd use 10/2 for all 15a circuts and 8/2 if it'll fit in the 20a outlets basicly I'd find the largest wire size thet'll fit the outlet and use that whats a hundred or 2 on a major project? I douby you will find any straight blade 20 amp outlets that will accept wiring beyond 10 AWG. Wayne |
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to Fronkman
said by Fronkman:as far as cost is concerned, a 33% premium IS a lot. sure, in a job being done by a professional electrician the difference in cost is small because LABOR is the majority of the price anyway. however, *I* am the labor in this case and differences in materials cost is important. 12/2 is 33% more expensive and 20A devices are 500% more expensive.
You don't have to put 20A outlets and breakers. You probably need ~1000ft of wire total. You DO need a good amount of 12/2 How much would it cost you to buy a 1000ft 12/2 spool vs 500ft of 12/2 and 500ft of 14/2? You're talking about a 33% premium on the 12/2, but that is only on the portions that don't need 12/2 Looking at HD prices 1000ft of 12/2 is $287, you could split as 500ft 12/2 @140 plus 500ft @100 and hope you don't end up with too much leftovers of any, and you save a total of $50. MAYBE. That if you don't need an extra piece of 12/2 so you have to spend on a 100ft spool and lose all your potential savings. |
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sk1939
Premium Member
join:2010-10-23
Frederick, MD |
to Fronkman
The 20A devices are not that expensive, I just bought a dozen for $1.67 each (Arrow-Hart spec-grade, which is not Federal spec grade mind you).
DO NOT BUY THE $.50 OUTLETS YOU SEE EN MASSE AT LOWES DEPOT. |
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| sk1939 |
to 49528867
True, although 20A Twist-Locks will accept up to 8 Gauge wire I believe. |
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