Every house I've lived in had all the breakers in one place, a load center (aka breaker panel) right next to the service entrance (aka electric meter). All circuits in the house are home-run to this location. (One house had a small load center, and a small subpanel next to it, but otherwise it was the same.)
Lots of cables run right next to each other, from the load center to other parts of the house. The worst case is usually the kitchen. You may have a separate circuit for each of:
- fridge
- appliance receps (often two circuits or an MWBC)
- disposer
- dishwasher
- range
- wall clock
That's a lot of copper all running to one place.
As a long-time computer programmer, I'm used to breaking down bigger problems in to smaller ones, making things uniform/repeatable, etc. So I'm often tempted to apply this in other domains, mostly because it's familiar.
Instead of running a bundle of 12AWG cables to the kitchen, you could run one larger cable to a kitchen subpanel, and then fork off short local circuits from there.
You can use a lot less copper this way. For example, consider a typical installation of 6 circuits, 20A each. There's a hot, neutral, and ground - 12 conductors total. Even though total ampacity of all 6 circuits is 60A @ 240V, you don't need to feed that much to the subpanel, since the copper is shared across all the circuits. The subpanel could be 50A or less. And you only have 4 conductors, not 12. (Of course, if you guess too low, the subpanel's main breaker will trip, which is annoying. So don't take it too far.)
If you have an electric range, the subpanel circuit will be pretty hefty. You may decide to take the extra trouble to use an aluminum conductor, which is often much cheaper than copper. I usually avoid aluminum inside a dwelling because of increased fire risk, but in this case it may be worth it. Just take the time to make sure it's done right.
This approach will make motors (like a blender) last longer, and reduce power losses to heat. If you size the copper for the sum of the loads, but the loads are intermittent, each load will have a lot more headroom almost all of the time.
Another advantage is that adding a new circuit to your kitchen is much easier - the panel is right there already. Also, if you ever run out of room in that panel, it's easier to upgrade to a larger one, since you don't have to get the power company to disconnect/reconnect the main feeder - just shut off the upstream breaker. (This is also a reason I think the main disconnect for a service should be separate from the main load center. Put it outside in the same box as the meter.)
Also, if you overload a circuit, the breaker that trips is right there in the same room with you. You don't have to go far to reset it.
There are some disadvantages, of course. The subpanel itself and the upstream breaker cost money. Not much in the grand scheme of a house, but still. The electrician has a little more wiring work to do (but less work pulling cables from one place to another). Some people find a subpanel in a kitchen to be ugly (but not me!).
If you short a circuit, it could trip any of several breakers - the breaker on this circuit, the upstream breaker for the subpanel, or even the main breaker for the house. This is different from when you merely overload a circuit by plugging in too many appliances, say trying to pull 25A on a 20A circuit. A short is effectively pulling thousands of amps on the circuit, and whichever breaker happens to trip fastest is the one that you will have to reset.
Finally, it's weird. Most people like their homes to be conventional. Building trades are steeped in tradition.
While I'm at it, why not run a small subpanel to *every* room? A small load center is $15 or so, so the extra cost is not huge. If you're wiring 2 circuits to a room, using a subpanel saves you a couple conductors (hot-hot-neutral-ground instead of hot-neutral-ground x 2), much like using a MWBC (multi-wire branch circuit). Now, if you ever want a 3rd circuit in the room, it's easy to add.
This whole idea is derived from MWBCs. Some electricians swear by them (twice the capacity with just 30% more copper) while others abhor them (risk of 240V exposure if neutral is broken; bonded 2-pole breaker required). A subpanel to split the MWBC in to single-leg circuits, close to point of use, can work out really nicely.
Maybe electricians already thought of all this and don't put subpanels all over the place for good reason. I haven't heard that reason yet, but I'll keep my ears open.
