wire gauge / breaker rating

[Greg Fretwell]

The toaster wire heat needs full circuit ampacity, based on the labelling of the air handler and the installed heat kit. The confusion is in the condenser wiring, usually smaller than the heat. You set the breaker size to the overcurrent rating and the wire size to circuit ampacity. That will not be what you usually see based on 240.4(D). (20a=12ga 30a=10ga etc)
Motors are under a different rule.

[Bruce A. King]

With the price of copper we will probably start seeing some creative wiring practices. I did a 3BR house the other day that only had one arc-fault breaker on a single circuit for all bedrooms.

[Greg Fretwell]

The basic rule of thumb is 3va per sq/ft so a 20a breaker could serve 800 sq/ft of bedroom. I doubt anyone is actually measuring this in plan review and the code language is not really there but that is a guideline.

[Paul W. Abernathy]

Bruce,

While that seems poor electrical design as I would think (4) bedrooms and only (1) AFCI circuit is rather weak.

What we see is many electricians today ( well the ones I know and teach ) are starting to put (1) AFCI on the bedroom receptacles and (1) on the bedroom Lighting outlets...that way they can get (2) rooms with a different circuit for the recepts than the lights...so the lights dont have that dim effect if a larger load is placed on it for some reason...

But again my personal feeling is on 14 AWG circuit AFCI or not....no more than 12-14 items per circuit....and 14 is my max.....but we all know situations arrise......add one here " quote from the builder/buyer " and well....you know.

[Mike Parks]

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 only be required to be installed to
serve the connected load.