What you need to know:
Routing the cables:
- Staying organized. Try to pick a path, or a few main paths, to stick to for the majority of the home runs from your panel to the first location in your circuit. This not only looks better and will help you to keep track of things for yourself, but it looks better to the inspector and makes their job easier, which can save you trouble in the long run.
- Stay out of the way! Cables are fairly easy to damage. Keep them clear of anything that gets hot, moves, pinches, or still has work left to be done on it. You are required to stay a minimum of six feet from any attic access, or protect the cable within that distance.
- Avoid Bundling. While you want to route your cables close to each other, avoid stacking them together whenever possible. The process of conducting electricity creates heat, and the cables need to be able to dissipate this. Avoid more than a couple of cables running through the same holes also. Too many cables stacked or ran through the same holes together can be considered "bundling" by the inspector, and get you turned down and issued a correction notice.
- Stay away from the edge. Try to stay in or on the center of the surface you are running on or through. Any cables within 1 1/4 inches of the face of a stud or joist will need to be protected. If you have to run your cable in that 1 1/4 inch range, protect it with a "nail plate".
- Notching the wood. If you have to notch the wood to get your cable where you need it, do so sparingly. Notching wood requires you to use a "nail plate" over the notch, and some wood members may be weakened by notching.
Securing and Supporting
- Stapling the runs. Cables need to be secured with approved staples or straps every 4 1/2 feet at a maximum. This is when ran on a surface or on the top of trusses. When running through holes bored in the studs of a wall, the cables are considered properly supported and need no stapling is required in those sections as long as the spacing between the holes does not exceed 4 1/2 feet.
- Securing by the boxes. Cables need to be secured with a staple or strap within 12 inches of a box or device.
- Fishing. When doing remodel work, where the surfaces through which you are running are already covered, the securing and supporting requirements do not apply.
How much wire?
- Leave enough cable at the box. The code requires at leats 6 inches of free conductor in a box. This is measured from the back, inside of the box. I know wire is expensive, but do yourself a favor and leave a little more than the required minimum. You'll thank yourself later.