# of outlets on a circuit

[Eddie702]

I know this is a common question that has no answer as you can probably put as many outlets as possible on a circuit that you want.

Back when I was doing houses, I used to follow the 180 va/ outlet so a 15A general use circuit I would put 10 receptacles or 10 lights or 5 receptacles and 5 lights etc as a 15 amp circuit is 1800va.

What is the consensus of what you do? I used to shoot for 10 sometimes it was 9 or 12.. Is this a reasonable approach?

 

[ptonsparky]

Reasonable. I think general branch circuits are loaded even lighter now. Power supplies different, LEDs, etc.

 

[infinity]

? I used to shoot for 10 sometimes it was 9 or 12.. Is this a reasonable approach?

Reasonable maybe. Not a code requirement to use the 180 VA for dwellings. Given the cost of AFCI breakers guys seem to be installing many more than 9 or 10 receptacles on a 15 amp circuit.

 

[winnie]

IMHO totally reasonable to use 180VA per receptacle as a design rule of thumb for residential receptacle circuits.

Probably excessive for most lighting outlets. Most residential lamps are much smaller loads these days.

 

[Strathead]

Correct me if I am wrong. (Commercial only, I like to say I am allergic to romex). I thought the code determines the minimum number of general purpose circuits required for lighting and power and then requires the outlets to be evenly distributed. Shouldn't that determine the number of receptacles on each circuit?

 

[infinity]

Correct me if I am wrong. (Commercial only, I like to say I am allergic to romex). I thought the code determines the minimum number of general purpose circuits required for lighting and power and then requires the outlets to be evenly distributed. Shouldn't that determine the number of receptacles on each circuit?

The NEC uses the term Evenly Proportioned Among Branch Circuits. Not knowing what is going to be plugged into a receptacle there is no requirement to have the same number of receptacles on a circuit. It does mention that the load "shall be evenly proportioned among multioutlet branch circuits within the panelboard".

210.11(B) Load Evenly Proportioned Among Branch Circuits.
Where the load is calculated on the basis of volt-amperes per square meter or per square foot, the wiring system up to and including the branch-circuit panelboard(s) shall be provided to serve not less than the calculated load. This load shall be evenly proportioned among multioutlet branch circuits within the panelboard(s). Branch-circuit overcurrent devices and circuits shall be required to be installed only to serve the
connected load.

 

[nizak]

What I’m seeing in new residential construction is basically a 15A circuit to every habitable room for receptacles.

The lighting ends up being 2 15A circuits for the entire house.
I think most residential electricians do it this way because it’s “ easy”

My new construction method is # 12 for all receptacles regardless of location.
Obviously ,dedicated circuits all installed per code.

As an example , 3K sq ft house gets 4 15A lighting circuits. At finish, load check is done and those 4 may be reduced to 3 in the panel depending on load.

I know I’ll catch flack for the #12 on general use receptacles but I’ve never had a call back or concern.
Plus I price it into the bid.

 

[AC\DC]

Depend on what they pay for/— they wanna pay for a bedroom on each circuit. They don’t then two or three bedrooms, tied together.

 

[ptonsparky]

Advantage of the 12 is less VD and with the size of todays homes may make a difference for those areas that enforce VD restrictions.

 

[ptonsparky]

I never had a call back on 15 amp circuits feeding two or three bedrooms.

 

[Rick 0920]

With requirements for AFCI and GFCI going crazy like they are, I'm seeing circuits wired today a little heavier than they used to be. Different municipalities can be more stringent than the NEC. In Florida, one county used to limit the number of receptacles on a 15 amp circuit to 6. You could have a combination of 8 if putting receptacles and lights on the circuit. And 10 lights max on a circuit. The NEC doesn't state this. What it does state is the minimum number of branch circuits based on square footage for the General Lighting Load. With AFCI/GFCI requirements going nuts, a lot of contractors are just biting the bullet and putting dual function breakers in for all 120v branch circuits. I think that's what the manufacturers set out to do in the first place.

 

[nizak]

Advantage of the 12 is less VD and with the size of today’s homes may make a difference for those areas that enforce VD restrictions.

Some of these home runs in large homes where there may not be a sub panel placed mid point can easily measure 200+ ft.

VD isn’t enforced in my area. If it was most new builds would fail.

I’m not knocking anyone who installs circuits with known VD. I’d it’s not a code requirement , why do it.

You bring a home run to a room for instance. By the time you wire up and down, over around , and end up at the last receptacle you nay have added another 100’ ft to it.

Who knows what may be plugged into that last receptacle 300’ from the panel .

Again it’s just my preference but I’ll set a sub panel mid home if I can.

 

[Little Bill]

Only #12 I put in is for the required 20A circuits. Unless there is a known load in an area not requiring 20A, then I would wire accordingly. I don't count receptacles, just go by spacing rules and any requests from customer.
I wired a 5K sq ft house a couple of years ago with all #14, except for required 20A, no call backs yet.

 

[tortuga]

In residential (dwelling unit) each general purpose lighting, receptacle and small fan motor branch circuit load is calculated per square foot of area served.
For example a 600 SQFT area requires a minimum of one 15A circuit. A 601 SQFT addition requires two.

 

[winnie]

I know I’ll catch flack for the #12 on general use receptacles but I’ve never had a call back or concern.
Plus I price it into the bid.

You won't get flack from me for doing more than code requires. You might get flack from your accountant...but if it is part of your business model to do more than code allows and charge accordingly, then more power to you.

-Jonathan

 

[Dennis Alwon]

I never had a call back on 15 amp circuits feeding two or three bedrooms.

I had one call back because I installed 2 bath receptacles on one circuit in 2 different bathrooms. The complaint was the kids can't blow dry their hair at the same time. No matter what you do someone will complain. I did always put the master bath receptacles on their own circuit.

 

[LarryFine]

. . . then more power to you.

?

 

[Eddie702]

I was always told from a design standpoint not to run a circuit to each room. If you have trouble with one circuit then that room is down. If you mix circuits between rooms then if you have a problem with a circuit chances are something in that room will work. You will at laest have a light or a place to put a light in.

 

[tortuga]

One way of thinking of residential load is by "load density" not VA load per receptacle,
By intersecting the NEC 3 VA per ft2 general branch circuit load with the 6-foot spacing rule, we can determine the "Venn-style" load density of a circuit. A 15A, 120V circuit (1800 VA) serves a maximum of 600 SQFT; in no case can a 15A branch circuit serve an area larger than this. As room geometry changes, the minimum number of required outlets shifts, causing the "implied load" per outlet to fluctuate based on available "wall space" (defined as any wall segment ≥2 feet). You could in theory construct a 600 SQFT space served by one receptacle so the maximum loads for a 600 SQFT area look something like;

Configuration​	Outlets Required​	Implied VA per Outlet​
Standard Square room​	8​	225 VA​
Circular Room​	7​	257 VA​
3-Sides Glass sun room​	2​	900 VA​
Modern house all glass roll up doors?​	1​	1800 VA​

 

[infinity]

One way of thinking of residential load is by "load density" not VA load per receptacle,
By intersecting the NEC 3 VA per ft2 general branch circuit load with the 6-foot spacing rule, we can determine the "Venn-style" load density of a circuit. A 15A, 120V circuit (1800 VA) serves a maximum of 600 SQFT; in no case can a 15A branch circuit serve an area larger than this. As room geometry changes, the minimum number of required outlets shifts, causing the "implied load" per outlet to fluctuate based on available "wall space" (defined as any wall segment ≥2 feet). You could in theory construct a 600 SQFT space served by one receptacle so the maximum loads for a 600 SQFT area look something like;

Configuration​	Outlets Required​	Implied VA per Outlet​
Standard Square room​	8​	225 VA​
Circular Room​	7​	257 VA​
3-Sides Glass sun room​	2​	900 VA​
Modern house all glass roll up doors?​	1​	1800 VA​

Interesting concept but nowhere in the NEC is it required to consider the room size when figuring out how many receptacles you want to put on a circuit.