how many outlets on a breaker

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Beverly

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:-? what method of electrical calculation do you use to figure out, how many outlets to put on a 15 & 20 amp circuit breaker ?
 
Beverly said:
:-? what method of electrical calculation do you use to figure out, how many outlets to put on a 15 & 20 amp circuit breaker ?
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Assuming (uh-oh!) you mean receptacle outlets, I use the "what's-the-load" method. Obvious are the single-receptacle circuits, like refrigerator, microwave, sump pump, central vacuum, etc. For kitchen counter receptacles, I like two or three.

Since I try to keep receptacle and lighting circuits separate, I can put two or three bedrooms on one 20-amp circuit. A master bedroom and a family room would probably each get its own receptacle circuit.

Direct answer: I'm not a believer that the load calculations directly translate to a specific limit on receptacle count. What if you decrease the spacing between them? If you want receptacles four feet apart, would one room require 5 or 6 circuits?
 
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stickboy1375 said:
Larry you really wire bedrooms with #12 wire? IMO, I don't think I could justify that...
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Lighting, no; receptacles, sometimes.

In a typical 3-b/r, 1.5- or 2-bath house, one 15-amp lighting circuit for the bedroom/bath/hallway half and one for the kitchen/dining-room/living-room half. One 20-amp receptacle circuit supplies all of the bedroom and hallway receptacles, and a 15- or 20-amp circuit for the living-room and misc. (such as exterior and attic/crawl receptacles.)

In the big (7800 sq.ft.+) that I've posted a few pix from, (every bedroom has its own full bath), I gave each bedroom/bathroom area its own 15-amp receptacle circuit and its own 15-amp lighting circuit (fan/light, recessed lights, closet light, bath vanity and fan/light combo). The homeowner paid for materials, by the way.

When minimal materials cost is not top priority (and even when it is, if I can), I try to keep system performance in mind. The lights don't dim when the TV is turned on, or even a vacuum. I believe in sub-panels when practical, which also helps in minimizing voltage drop due to load diversification on feeders.
 
LarryFine said:
Lighting, no; receptacles, sometimes.

In a typical 3-b/r, 1.5- or 2-bath house, one 15-amp lighting circuit for the bedroom/bath/hallway half and one for the kitchen/dining-room/living-room half. One 20-amp receptacle circuit supplies all of the bedroom and hallway receptacles, and a 15- or 20-amp circuit for the living-room and misc. (such as exterior and attic/crawl receptacles.)
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How do you route that that it makes sense to have a separate lighting circuit? I think you have the right idea for reasons unrelated to cost, but in terms of having extra wires running around, that seems wasteful.

When I lay out a bedroom, I take the home run to the light, 12/3 from the light to the switch, then exit the switch box out the bottom to the receptacles. If it's two small bedrooms I'll put the second light on the end of the run after hitting that room's receptacles. The guys I've been working with like to feed the box for the switch, then 12/2 (or 12/3) to the light, and 12/2 out the bottom to the receptacles. I like my way better because I know which wires in the boxes go where, and I'm not scratching my head wondering which wire on top is for the home run and which is for the light. Plus their way seems more wasteful. The only time I don't go that way is if I'm wiring for a ceiling fan as well. Then a roll of 12/4 would come in handy ...
 
tallgirl said:
When I lay out a bedroom, I take the home run to the light, 12/3 from the light to the switch, then exit the switch box out the bottom to the receptacles.
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When I lay out a bedroom, the lighting is #14 jumped from the smoke detector (which is necessarily already in the bedroom and normally very near or over the light switch). The receptacles are a 12-2 home run for each bedroom. As basements and panels in basements are standard fare in my area, the bedroom lighting home run will basically run from the panel to the basement smoke detector; often only 10 or 15 feet away.
 
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mdshunk said:
When I lay out a bedroom, the lighting is #14 jumped from the smoke detector (which is necessarily already in the bedroom and normally very near or over the light switch). The receptacles are a 12-2 home run for each bedroom. As basements and panels in basements are standard fare in my area, the bedroom lighting home run will basically run from the panel to the basement smoke detector; often only 10 or 15 feet away.
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D'OH! I hadn't thought of that.

This is what I get for learning how to do this before smokies were a requirement. Somehow I thought smokies had to be on their own circuit with nothing else on them (which is how I do them -- home run to the first, then 12/3 to the rest).

So ... what else can go on a circuit with a smokie?

(And I assume we need a "Tips and Techniques" forum one of these days ...)
 
tallgirl said:
So ... what else can go on a circuit with a smokie?
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Anything you want, unless there's a jurisdictional requirement or limitation. Seems a waste of a circuit to only have a few milliamps of load with just the smokes. Might as well use that circuit for bedroom lighting, I say to myself. It's already AFCI protected.
 
It's actually a good idea to have the smokes on with something else, such as bedroom lights, so that if that circuit trips, the HO will notice. If it is only smokes, they probably won't notice until the dead battery chirp begins.
 
We have strayed from the original post somewhat. On bedroom circuits I usually tryed not to have more then 8 recepts on a 15 and 11 on a 20 amp circuit. Someone stated 2 recepts on kitchen circuits, I've done some kitchen remodels that would have required 15 SA circuits if I did that. I never used to put recept and lighting on the same circuits, but with the AFCI I do now to save money.

Tallgirl why do you use 12 wire to the smokes?
 
Paul B said:
We have strayed from the original post somewhat. On bedroom circuits I usually tryed not to have more then 8 recepts on a 15 and 11 on a 20 amp circuit. Someone stated 2 recepts on kitchen circuits, I've done some kitchen remodels that would have required 15 SA circuits if I did that. I never used to put recept and lighting on the same circuits, but with the AFCI I do now to save money.

Tallgirl why do you use 12 wire to the smokes?
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Because I'm told to? (Yes, that's really the answer.)

I use #12 all over the place. You'd think I was addicted to the stuff or something.
 
Beverly said:
:-? what method of electrical calculation do you use to figure out, how many outlets to put on a 15 & 20 amp circuit breaker ?
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Give you the legals-

By load -10 receptacles on a 15 amp circuit = 1800va.

By load -13 receptacles on a 20 amp circuit = 2340va.

220.44 allows a demand factor of 50% after the first 10,000va.
That's 55 duplex receptacles 180va x 55 = 9900va.


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For residential it's all about square foot. 3va x size of house (220.12 see the FPN too). so size of house / 3va = sq. ft. / 2340 (20a) or 1800 (15a) for breaker count in the panel for general lighting.

Keep in mind, this is bare bone minimums though. there will probably be more.

To get an idea of how calculations work, go to the back of your NEC and see Annes D Examlples. Also see if you can get access to a NEC handbook ($100+) from somebody on crew, lots of explanation there on everything.

edit was horizontal bar to reflect difference of other than dwelling unit on top/ dwelling unit(s) on bottom
 
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Rocky, we need to note that in dwellings you can put as many as you want on a circuit, in other than dwellings it is limited to the 180 va per receptacle.

Roger
 
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How many receptacles on a circuit

How many receptacles on a circuit

If a 20 Amp circuit, take 20 times 120. Divide that by 180Watts per receptacles and you'll get 13 receptacles. Note that the code allows you to use the entire 20Amps in this calculation, not 80% of that or 16 amps. I find this to be a common misconception.

That having been said, I never put more than 7 receptacles on a single circuit.

Hope that helps.
 
Unlimited receptacles on a circuit in a dwelling unit

Unlimited receptacles on a circuit in a dwelling unit

I just read on one of these postings that you can put as many receptacles as you wish on a circuit in a dwelling unit. Where is this indicated in the code?
 
Mike, see 220.14(J) it does not give a value to dwelling unit receptacles. IMO, The NEC takes into consideration that in most situations, the number of general receptacles on a circuit in dwelling units are more location oriented than load.

In my house the number of lamps, TV,s, computer, etc ... in any given room doesn't ever change much, but when my wife wants to change the lay out (which is more than I want) additional receptacles are a blessing. There is no need for more circuits into the rooms as the load doesn't change.


Roger
 
roger said:
Rocky, we need to note that in dwellings you can put as many as you want on a circuit, in other than dwellings it is limited to the 180 va per receptacle.

Roger
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I would still use the 180VA per duplex receptacle, unless directed to do otherwise, and keep the lights separate from the recpetacle outlets. I understand that it is over the minimum required by NEC, but I am old school.

IMO, the Code is deficient in this area because of all the electronic gizmo's and what not's. It irriates me to no end to plug in an iron, and see the lights dim.
 
kingpb said:
I would still use the 180VA per duplex receptacle, unless directed to do otherwise, and keep the lights separate from the recpetacle outlets. I understand that it is over the minimum required by NEC, but I am old school.

IMO, the Code is deficient in this area because of all the electronic gizmo's and what not's. It irriates me to no end to plug in an iron, and see the lights dim.
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Your irritation is not from the number of outlets on the circuit, it is from VD considerations (or lack of) in the design of the circuit.

The light (even if singular) could dim with this irons load with only one receptacle on the circuit if other variables are not included in the wiring of the circuit.

Roger
 
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Unless you have a specific load(s) then assume these will be convenience receptacles with a 180va load on each (NEC 220.14(I)). If you also assume that they will be in use less than three hours (non-continuous load)you can use 100% of the breaker rating (NEC210.20(A))then 20X120=2400; 2400/180=13.33. For a 15 amp breaker you can have 10 receptacles on a CB. This would be the max number of receptacles you can out on a 15A or 20A CB. I always assume 80% breaker rating and figure that before the project is finished there may be several more added so I usually start with 6 on a CB. I try to limit the max to 8 if possible. You never know when someone will plug in a hair dryer.
 
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