number of general receptacle circuits in custom homes

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JoeNorm

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In residential custom homes where budget is not a major limiting factor how do you decide number of receptacle circuits? Do you give each room it's own circuit?

I find I often overthink and go overboard here. But at the same time I don't want to skimp and create a situation where a breaker trips do to overload. As we all know an entire 3 bedroom floor could be on a single circuit(aside from the bathroom) and likely never know the difference from being on three separate circuits.

But it seems more common to use more and more circuits. I often see less than 1500sqft houses have a full 42 space panel.

So how do approach and think about this?
 
The only thing that makes me hesitate from putting 2-3 bedrooms on the same circuit is window AC's, and that is going to vary on location. In warmer climates where central AC is pretty much universal ,its not an issue, but here in upstate NY, hardly anyone has central AC, so window units become a fairly common thing during those few hot spells we have. In those cases, you have to make the decision to just do each BR on its own 20 amp circuit, or provide a dedicated 20a circuit next to a window. Sometimes i go with the latter and just blank it off for inspection and hook it up later (usually without AFCI) if its needed. I discuss options with client.

I circuit things differently every time I think.
 
I prefer separate 20a receptacle circuits and 15a lighting circuits, like we do in kitchens, and for similar reasons. I have had customers who tripped bedroom circuits when vacuuming with all of the lights on when all wired together on 15a circuits. This can happen even with each room on its own breaker.

One 20a circuit can supply many more receptacles because of that 5a extra headroom. The lighting in bedrooms with ceiling lights and fans, closet and hallway lights, bath lights and fans, etc., will be a relatively fixed, known load. The same applies to kitchen, dining room, hall and closets, etc., downstairs.

In any home, especially a custom home, you should walk from room to with the customer and discuss placement of lighting, receptacles, switches, low-voltage outlets, etc. For example, for kitchen counter receptacles, I suggest as few as two per circuit. Always suggest under-cabinet LED ribbon lighting.

With more than one panel, divide circuits between generator and non-generator panels, even if you're not wiring for one now, and leave enough space and wire to add an ATS in the future. Also, plan for other additions, like outside lighting and feeders. In a very large house, use a sub-panel or two.

Added: Always, always, always wire every panel as if it will be a sub-panel.
 
I discuss with the client of potential use of the room. Any heaters, special computers, ....

But I generally have two circuits every three bedrooms. Every other receptacle is circuit A and then B.

Lighting circuit is on 15A and I don't mix it with the 20A receptacle circuits.
 
LarryFine said:
I prefer separate 20a receptacle circuits and 15a lighting circuits, like we do in kitchens, and for similar reasons. I have had customers who tripped bedroom circuits when vacuuming with all of the lights on when all wired together on 15a circuits. This can happen even with each room on its own breaker.

One 20a circuit can supply many more receptacles because of that 5a extra headroom. The lighting in bedrooms with ceiling lights and fans, closet and hallway lights, bath lights and fans, etc., will be a relatively fixed, known load. The same applies to kitchen, dining room, hall and closets, etc., downstairs.

In any home, especially a custom home, you should walk from room to with the customer and discuss placement of lighting, receptacles, switches, low-voltage outlets, etc. For example, for kitchen counter receptacles, I suggest as few as two per circuit. Always suggest under-cabinet LED ribbon lighting.

With more than one panel, divide circuits between generator and non-generator panels, even if you're not wiring for one now, and leave enough space and wire to add an ATS in the future. Also, plan for other additions, like outside lighting and feeders. In a very large house, use a sub-panel or two.

Added: Always, always, always wire every panel as if it will be a sub-panel.
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15 amp lighting and 20 amp receptacles is the way I almost always do new construction. Almost always have done as well, even where I used to work before going on my own we did that most the time. I think is even more important today to do that with LED's and the way they respond to voltage changes and other loads on the same circuit doesn't help with the voltage change issue. I usually put 2 or 3 bedrooms on a 20 amp receptacle circuit, sometimes even four.

15 amp light circuit- I probably install more circuits than needed. Done new homes with 4 light circuits that likely would be able to get it all on just one circuit. Do have some concern with AFCI's though and try not to load them too heavily with electronic driven loads as I can see that possibly contributing to nuisance tripping.
 
Thanks. To be clear I never mix receptacles and lighting, one reason being I never want to deal with #12 when making up switches. Occasionally I will pop out of a switch box down to a receptacle if it looks like it won't be used much like in a hallway. I don't think I have ever made a dedicated 15a receptacle circuit, they have always been 20a. Just the way it's done around here.

Regarding Window AC, for one that is not my climate. And two these are usually houses where the mechanicals have been pretty highly engineered and planned out.
 
Sometimes I do put bath lights on with the same bath receptacle, but most the time I put them on with other lights in nearby rooms. Every project has it's reasons to do it one way vs the other.
 
I only wired one custom home where the owner was a rich gadget person. He wanted double duplex receptacles mounted every two feet on counter top, two switched controlled receptacles in each of the five bedrooms ( one was for one of the double duplex receptacles under each window for Christmas lights or candles, So many floodlights on outside of the house had to install a two pole relay, hi hats inside of every closet, at least a dozen three way & halve dozen four way switches, etc. Only bad thing was he kept making major changes after wires were pulled. Had no problems getting paid for the changes but would prefer to only install a circuit once. Him & the builder moved laundry chute four times where of course there was at least a dozen NM cables that had to be moved & of course three of the moves cables were too short.
 
1500 x 3va 4500
20A x 120v 2400 = 1.875 (2) 20A circuits required for a 1500 sq. ft. house. Almost all electricians that I know of will not load circuits this heavy. The NEC has no requirements for number of outlets on a circuit, only number of circuits. Local
codes may have more stringent requirements. Today, with AFCI and GFCI requirements for most circuits,
circuits are loaded a little heavier to try to reduce the number of more expensive breakers. Higher prices
of copper are offset by pulling fewer home runs.
 
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JoeNorm said:
Thanks. To be clear I never mix receptacles and lighting, one reason being I never want to deal with #12 when making up switches. Occasionally I will pop out of a switch box down to a receptacle if it looks like it won't be used much like in a hallway. I don't think I have ever made a dedicated 15a receptacle circuit, they have always been 20a. Just the way it's done around here.

Regarding Window AC, for one that is not my climate. And two these are usually houses where the mechanicals have been pretty highly engineered and planned out.
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Another reason to keep receptacles and lighting separate is so popping the circuit breaker for an outlet won't leave you in the dark!
 
With receptacles, luminaires, ceiling fans, and smoke detectors all needing to be on AFCI circuits, you will see these outlets combined more and more these days. Some states that I've worked in don't allow 15 amp circuits at all. Others, like Florida allow 15 amp circuits for lighting and receptacles except those required by the NEC to be 20 amp. I guess you would need to wear a headlamp when troubleshooting. :)
 
I tend to over engineer things, but this is what I'll do with my own build...
Each room on a 20A breaker, outlets only
All outlets to be NEMA 5-20R, heavy duty
Each floor with it's own 15A lighting main - no receps whatsoever.
Each kitchen recep on it's own 20A with a NEMA 5-20R (We tend to buy commercial grade appliances, like 1800watt air fryers, Waring 2000 watt toaster, etc, etc)
 
I haven't wired a new house this year, just doing remodels.

But it kinda depends on the house, and how it's laid out. I only know this - if I can ever help it, I'm not running 2 or 3 cables through an area where 1 will do.

I wire about 8 general openings on a circuit. I don't care if it's all lights, all receptacles, or a mix. Same room, different rooms, hallways, doesn't matter. Easiest way to wire those openings together, that's where I'm at

I have never in my life wired a house thinking somebody's going to be there troubleshooting. If I had that concern, I would have stopped wiring 30 years ago.

I'm not at all concerned with what somebody 15 years later may or may not have going on. None of my business.
have enough in my brain trying to keep up with dozens of municipalities and the various code cycles, I don't need to ad psychic to my job description.

I do put in a lot more kitchen and bath circuits than most everybody I know. No more than 3 kitchen receps, and no more than 2 bathroom receps is my general rule
 
I feel my job which was designed has the opposite issue. An example is 4 hallway receptacles on a circuit. Circuits for an igniter for a fireplace. Another for a television.
 
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