20 amp wire on 15 amp breaker?

[gaelectric]

I like to offer an optional upgrade to 20 amp 12AWG receptacle circuits to my home owners. Some people jump on it and I make a little on it. Otherwise it gets 14AWG.
However I never use 12 on a lighting circuit cause the make up and trim out is a booger.

 

[bikeindy]

I like to offer an optional upgrade to 20 amp 12AWG receptacle circuits to my home owners. Some people jump on it and I make a little on it. Otherwise it gets 14AWG.
However I never use 12 on a lighting circuit cause the make up and trim out is a booger.

If you designed the layout correctly what is there to "upgrade" it's not like going from a V6 to a V8, Nothing is going to operate better or wear out in less time just because it has a 20 A wire and breaker. I don't get it, if I had a customer tell me they were sold on that I would tell them they were ripped off.

 

[tallgirl]

Vacuum cleaners treadmills and humidifiers are common appliances and I doubt that they would cause tripping of a 15amp circuit as they would not likely to be used at the same time.

Maybe not, but one reason I like separating lighting and receptacle circuits (and while I'm at it, maybe using one or two fewer circuits to cover the same area) is that vacuuming day is when all of the lights are most likely to be all full-on.

To say nothing of also having the washer and dryer and TV and a few other things on all at once. Plus whatever just happens to be on -- like that 4 x 60w light kit in the ceiling fan, plus the computer in the corner and ...

The thought of a 12A vacuum cleaner, 2A light kit, 3A computer, and 2A TeeVee all on at the same time on a 15A circuit makes me nervous. There are always going to be pathological cases and to me running 20A circuits for receptacles means they are less likely to occur.

In other words, among the benefits of doing it in kitchens and other work areas, like garages. I'd hate to be under the hood of a car with a running engine and have the lights go out because of some power tool or others.

The more I hang around y'all the more I see the wisdom of running lights and receptacles separately. But the fixation by some on 15A circuits I don't think I'll ever understand.

 

[LarryFine]

Julie, to me, it's more than simply running a larger gauge wire than necassary, it's about performance, and efficiency. Receptacle loads are not predictable, while lighting loads are.

From the electrician's point of view: let's say we're wiring a 3- or 4-bedroom house. For the kids' area, 3 or 4 rooms, I'd place all of the lighting, including bath, on one 15a circuit, and all of the receptacles, excluding bath, on one 20a circuit.

Let's say we wanted to just use two 15a circuits. How would you split that up? 1-1/2 rooms per circuit? Some receptacles and some lights? Plug in a vacuum and some lights go out, computer freezes, TV picture shrinks? No, thanks. Three circuits, maybe?

While a 15a circuit may indeed supply the load, it will have greater voltage drop doing it, especially during start-up surges. I've never had someone complain that the lights don't blink, only when they do.

A couple of weeks ago, I was in the orange store, and started a conversation with a young lady about 100-ft extension cords she was looking at for the 1500-watt heater she bought for her dog's doghouse.

I recommended the 10-gauge cord, while my electrical-engineer friend who was with me said that a little bit of voltage drop won't be a problem for a resistance heater, ignoring VD effects on the fan motor.

I pointed out that, while the overall current will be slightly lower, it would cost more, not less, to operate the heater, because the energy expended heating the cord would also cost, but would not contribute to warming the space (or opening the thermostat).

 

[peter d]

But the fixation by some on 15A circuits I don't think I'll ever understand.

I'm really baffled by this comment. You are basically shooting down a circuit that has literally been installed 10's, if not 100's, of millions of times.


My only guess is that you don't understand it because you're not an electrician and you're not employed in the electrical trade. If you don't do this everyday, an issue like "Why do we use 15 amp circuits?" won't make much sense.

 

[tallgirl]

I'm really baffled by this comment. You are basically shooting down a circuit that has literally been installed 10's, if not 100's, of millions of times.


My only guess is that you don't understand it because you're not an electrician and you're not employed in the electrical trade. If you don't do this everyday, an issue like "Why do we use 15 amp circuits?" won't make much sense.

Peter, I'm willing to be educated, but I'm not seeing anything persuasive.

The reason I'm not convinced is because the photo below isn't something that I've found to be all that unusual. I know that you and others don't believe circuits in houses wind up this heavily loaded, but I've got two or three circuits that don't have a lot of difficulty making it above 15 amps, and that's not counting the 12 amp vacuum cleaner. If you want, I'll go take pictures of some of the others.

For what it's worth, that's not the first box in that circuit. On "laundry night" this time of year that meter would have read over 15 amps. It's not even a badly run circuit. It has 500w of lighting on it, plus 3 duplex receptacles. That's it. It gets that high because there are common household appliances that take more than 10A.

I've wired several dozen houses in my life, including half a dozen or more since joining the Forum. I don't use 15 amp circuits on them because I'd hate to have 15 amp circuits in my house. The guys I work with most of the time -- mostly retired union electricians -- feel the same way I do. If you disagree, fine. That's your business.

 

[LarryFine]

What I don't understand is fixation on 20a circuits. 15a and 20a circuits each have their place. I have no hesitation to place a typical residential refrigerator on its own 15a circuit.

Receptacles usually get installed once, with only two cables in just about every box, while switching can have several cables in several-gang boxes. #12 can be a pain in these.

Plus, a standard 1-gang nail-on will easily accept 3 #14 cables plus a device, while a deep box is required for 3 #12's and a device, so you'd have to use them for switches.

 

[LarryFine]

It has 500w of lighting on it, plus 3 duplex receptacles. That's it. It gets that high because there are common household appliances that take more than 10A.

In my opinion, exactly why lighting (predictable) and receptacles (unpredictable) should be separated, and why receptacles fare better on 20a circuits where appliances might be used.

When laying out lighting-only circuits, use the fixtures' maxed-out ratings, and divide the loads balanced on however many 15a circuits it takes. You'd be suprised at how few circuits you'd need.

The receptacle circuits can also be 15a, as long as you're not trying to supply too many rooms with them. If you're going to supply two or three rooms' worth of receptacles, 20a is the way to go. The labor is about the same.

I the 7800+ sq.ft. house we did a couple of years ago, where the HO paid for materials, I supplied each bedroom with its own 15a receptacle circuit and 15a lighting circuit (which also covered the full bath each bedroom has.)

The whole point is that, since you cannot predict with certainty what receptacle loads will be, how can you determine how much lighting can be placed on a circuit supplying both? The 50% rule only leaves 7.5a for receptacles.

I'm not saying that all receptacle circuits should be 20a. But where you're likely to have either heavier loads or a greater quantity of loads, such as more than one room, each with TV's, electronics, etc., as well as plug-in lighting, it can be a good idea.

Again, it's as much about performance of the system as it is about the depth of boxes and stiffness of the wire. The wiring should be adequate for the load, not just in minimal compliance with the NEC. Anyone can do that. (Well, almost anyone.) I like to do it a little better.

 

[peter d]

The guys I work with most of the time -- mostly retired union electricians -- feel the same way I do. If you disagree, fine. That's your business.

Have these union electricians been employed doing mostly residential or commercial work in their careers?

The bottom line is simple. In this market, New England (and most others I would imagine,) you can't use "minimum #12 for everything" in the residential market. You won't compete, and you won't work. Period, end of story. There is a world of difference between wiring homes for free with donated material and wiring homes in a competitive market.

 

[augie47]

20 amp recpt

20 amp recpt

doesn't 210.21(B)(3) prohibit 20 amp recpetacles on 15 amp circuits?

 

[Dennis Alwon]

Have these union electricians been employed doing mostly residential or commercial work in their careers?

The bottom line is simple. In this market, New England (and most others I would imagine,) you can't use "minimum #12 for everything" in the residential market. You won't compete, and you won't work. Period, end of story. There is a world of difference between wiring homes for free with donated material and wiring homes in a competitive market.

Peter there are other markets out there where you don't have to be so competitive. I have not bid a house in the past 10 or so years and yet I have done 4 million dollar additions as well as $500,000 homes and rarely am I a day without work. Not everyone has all the constraints of bidding. This is not to say that 14 gauge wire isn't any good but I feel somewhat more comfortable with 12 gauge on recep. Part of that is I grew up in NYC where we never used 14 gauge except for control circuits or whatever but never for branch circuits. I still use 14 on lighting but I don't usually mix lighting and receptacles.

The bottom line everyone has their own reasons for wiring the way they do and we can talk until we are blue in the face and most of us won't change. Julie your way works for you, mine for me and Peter for himself. I don't think we can say who's way is better. As long as I can do what I feel better with I will continue to do so. I don't think it is a rip off to my customers as others have said in past threads. Nor do I think that 14 is a bad job. It's a bad job when the circuitry isn't thought out.

In defense of 14 gauge I don't think I have ever gone back to a relatively new house where the circuit was blowing on a 15 amp circuit because it was overloaded.

The attitude that "I" do it right and everyone else does it wrong is not fair. For sure, many do it wrong but we can't assume everyone using 14 gauge is a cheapskate.

 

[romeo]

20 amp wire on 15 amp breaker?

Peter, I'm willing to be educated, but I'm not seeing anything persuasive.

The reason I'm not convinced is because the photo below isn't something that I've found to be all that unusual. I know that you and others don't believe circuits in houses wind up this heavily loaded, but I've got two or three circuits that don't have a lot of difficulty making it above 15 amps, and that's not counting the 12 amp vacuum cleaner. If you want, I'll go take pictures of some of the others.

For what it's worth, that's not the first box in that circuit. On "laundry night" this time of year that meter would have read over 15 amps. It's not even a badly run circuit. It has 500w of lighting on it, plus 3 duplex receptacles. That's it. It gets that high because there are common household appliances that take more than 10A.

I've wired several dozen houses in my life, including half a dozen or more since joining the Forum. I don't use 15 amp circuits on them because I'd hate to have 15 amp circuits in my house. The guys I work with most of the time -- mostly retired union electricians -- feel the same way I do. If you disagree, fine. That's your business.

I thought we were talking about the benefits of using 20amp wire on a 15amp breaker. I still see no benefit to that other than if it is needed for vd.

If someone wishes to wire 20amp branch circuits where 15amp are code compliant,I have no problem with that.

 

[Dennis Alwon]

I thought we were talking about the benefits of using 20amp wire on a 15amp breaker. I still see no benefit to that other than if it is needed for vd.

We were Romeo but like all thread the mood changed.

 

[peter d]

Peter there are other markets out there where you don't have to be so competitive.

Of course, high end custom residential.

You're absolutely right, we will have to agree to disagree on this one. I think using #12 in residential for other than code required circuits is a waste of time and money. I doubt I will change my mind on this, and we'll have to leave it at that.

 

[augie47]

12 vs 14

12 vs 14

I hear this "argument" almost daily while inspecting. Each side has its persuasive points.
From an inspecting standpoint, I find "box fill" issues are, obvioulsy, more common using #12 on lighting. 75% of the homes I find wired with #12 lighting circuits have box fill violations (mostly on 2 gang boxes).
From my "wire twisting" days, I prefer #14 on lighting..far easier to work, less strain on devices, and, IMHO, makes a better connection with the fixture pigtails.
My vote: #12 on receptacles, #14 on lighting.

 

[George Stolz]

doesn't 210.21(B)(3) prohibit 20 amp recpetacles on 15 amp circuits?

If there's more than one receptacle on the circuit, yes.

The whole point is that, since you cannot predict with certainty what receptacle loads will be, how can you determine how much lighting can be placed on a circuit supplying both? The 50% rule only leaves 7.5a for receptacles.

Actually, lighting and general-use receptacles are on the same side of the coin. Fixed-in-place appliances are on the other side of the coin, 210.23(A)(2). A code compliant installation under the 2005 could use 15A for lighting and leave no remaining amps for a receptacle on the same circuit, IMO.

90.1(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

I think all sides of this discussion have their valid points. Each design will have it's benefits and it's drawbacks. An all-20A house will cost more to build. A minimal 20A house may trip breakers in use.

I think every electrician weighs the pros and cons differently. Minimally bid tract home EC's are more prone to push the envelope at every opportunity to save a buck, whereas one would hope that the EC bidding the higher-end tract homes, custom homes, and so forth would allow for above-code wiring.

If the minimalist has to continually return to the houses in a warranty period and break up their circuits after the fact, economics will demand that they design better in the future. Heck, I would be suprised if some of the larger ECs that do tracts even have a company-wide game plan. From my short experience, it rests entirely in the hands of the installer.

I thought it was a company standard to install weatherproofs and garage receptacles on a 20A circuit in the last company I was in, and once I floated around a bit I realized there was no standard within the company. One foreman flat out stated that we were the low bid, and bare-bones minimum was all they get.

However, they still did not push code minimums to the extreme they could have, just due to the warranty factor. I never seperated lighting and receptacles, except where required by code, and never had callbacks (that I recall) from the practice. That doesn't make it a good design, just another design.

The one thing I'd take away from this is that if you are an EC, and you care about certain design aspects, perhaps you should have them on paper so the guys in the field know it's important that these design considerations are standard.

 

[infinity]

doesn't 210.21(B)(3) prohibit 20 amp recpetacles on 15 amp circuits?

Yes, it prohibits more than one 20 amp receptacle on a 15 amp circuit. It does not prohibit a single 20 amp receptacle on a 15 amp circuit.

 

[iwirehouses]

I use 14 on lighting loads when I know it will be enough, like a finished basement with 10 recessed lights, but even so I would rather run twelve. They could be putting a 60 watt bulb there or a fixture with 18 50 watt halogen bulbs (had this happen). Box fill is the least of my worries, most boxes in the house will be fine, and if they arn't, I don't mind paying an extra 60 cents for the 3.5" deep box. I think every outlet should be on a 20 amp circuit. You never know whats going to be there, even if it is just a bedroom or a hall. I've even run a line for a refrigerator and put a 20 receptacle there,and thats it. Reason? I've seen houses with two refrigerators, usually totals around 15amps.

 

[tallgirl]

Have these union electricians been employed doing mostly residential or commercial work in their careers?

The bottom line is simple. In this market, New England (and most others I would imagine,) you can't use "minimum #12 for everything" in the residential market. You won't compete, and you won't work. Period, end of story. There is a world of difference between wiring homes for free with donated material and wiring homes in a competitive market.

Some were residential and others were industrial. I'm the only "non-professional" in the bunch, BTW.

Dennis' comment is spot-on. I learned most of what I know about electrical work having parents who built full-custom homes. Many of the practices I see described here might fly with tract home buyers, but absolutely would not fly with someone who's expecting a house that's significantly better than what they are going to get from the tract builders.

I think Celtic is the great champion of "raise your prices and you'll still have plenty of work". You can differentiate on quality or price. Or as we say in my biz -- "Cheap, fast, or reliable. Pick two." It's just not a foregone conclusion that you have to keep working faster and cheaper. There is a market out there for more reliable and more expensive.

 

[stickboy1375]

Just to throw in my 2 cents... Peter D and I can wire a thousand houses with #14 awg and never get one call back for a breaker tripping, like its been said before, it's all in the layout... Besides that if you are using #12, your only gaining 600 watts more per circuit... I really don't feel that is an advantage... especially in a bed room... I don't know what you people are finding in homes these days, but I generally find a tv, radio/alarm clock and a cordless phone... no need to panic on that one...