I own a home that was built in the 1960s in Hawaii. The home is of Traditional Japanese construction (all wood framing, flooring, w/plaster) from Japan. The wiring throughout is a black clad two conductor wiring (no ground) that I want to get rid of.
In addition to the age and composition of the wire, is the fact that the circuits are laid out in one of the most haphazard fashions that I have seen, and makes no real sense to me. Each wire from the breaker panel goes to a junction box, from which as many as 10 other wires sprout going to individual sockets, switches and lighting circuits, causing a large bundle of wire to be routed through a beam and into the wall cavity (see photo album).
I want to tear all of this wiring (and sockets, and breaker box) out and replace with newer material that is properly grounded. As a first step, I wanted to ask about circuit layout. Are residential circuits typically laid out in a by-room basis? For example a circuit for Living Room, a circuit for Master Bedroom, etc, or are they further divided by use? For example Kitchen Lighting, Kitchen Plugs, Living Room Lighting, Living Room Plugs?
I am doing this somewhat on the cheap, and I intend to have it permitted and inspected, but in an attempt to get something started on it, I wanted to at least conceptualize the circuit layout and scope of work.
Best Answer
Lights are typically put on a separate circuit from the receptacles, especially in places where GFCIs are required (kitchens, baths, and garages). This gives the benefit that when a breaker trips, you are not left in the dark. In many cases, #14 wire is used for lighting circuits whereas #12 wire is used for receptacle circuits. Keeping them on separate circuits allows you to use different size wires for each.
In addition, circuits are generally laid out by room, but it's not always the case that each circuit is one room. Adjacent rooms, or similar rooms, may be combined on one circuit, depending on the sizes of the rooms and how many receptacles each will contain. If your living room and dining room are adjacent, for instance, receptacles from both rooms may be on the same circuit, and lights from both rooms may be on the same circuit. Two adjacent bedrooms may share the same (AFCI-protected) circuit (this cuts down on the number of AFCI breakers needed, saving some expense). A great room that's very large may have it's own circuit for receptacles, but share a circuit for lights.
You may want to run additional dedicated circuits for unique equipment you plan to run, like computers in a home office (especially high-end machines), woodworking equipment, etc. There is nothing wrong with having a single receptacle be on a separate circuit in a room, or have half the room be on one circuit and half on another. Since you're doing the work now, when you've already lived there, you know better how you use the space, so set it up so it works best for you (while maintaining code).
Keep in mind any special-use circuits (oven, dryer, water heater, etc) will be their own circuit by definition, as these are usually 240V. Also keep in mind that the kitchen requires 2 separate small-appliance circuits, and the portion of those circuits in the kitchen need to be GFCI protected.
When you do get everything laid out and run, make sure to clearly label the panel. Perhaps even a separate diagram or spreadsheet showing which breaker every single receptacle, light, and switch is connected to. I might even go so far as to diagram where each wire is run through walls and ceilings. Digital files are cheap, and you never know when that info might come in handy. Along the same lines, consider installing conduit and/or low-voltage cable (networking / TV) at the same time; the best time to run new cable is when the walls are already open.