Most houses are wired in type NM cable (Romex). All wiring should be neat and align with vertical and horizontal building lines. This is not just an aesthetic decision for trades people; it locates wires predictably and makes for smoother pulling of wires, which results in a safer system.

When running cable along the length of studs or joists, keep the cable to the center of each, leaving a 1 1/4-in. minimum clearance on each side of the framing member. When running cable through studs, drill all holes at the same height so that the cable is run level to the floor. Drill holes 6 to 8 in. above or below all switch and receptacle boxes.
When running cable along the length of studs or joists, keep the cable to the center of each, leaving a 1 1/4-in. minimum clearance on each side of the framing member. When running cable through studs, drill all holes at the same height so that the cable is run level to the floor. Drill holes 6 to 8 in. above or below all switch and receptacle boxes.


Do not run No. 14-, 12-, or 10-gauge cable across joists or along the bottom edge of joists. They should run along the sides of joists, through bored holes, or along a continuous 1x attached to the joists.
Do not run No. 14-, 12-, or 10-gauge cable across joists or along the bottom edge of joists. They should run along the sides of joists, through bored holes, or along a continuous 1x attached to the joists.

One exception is in inaccessible attics where diagonal wiring paths may be acceptable.

Accessible attics with permanent stairs or built-in ladders require board protection throughout the attic on floors and walls/ceilings.  In accessible attics without permanent ladders or stairs, such protection is only required within 6 feet of the access opening.  In attics less than 30-in. high, no access is required.  Where there is no access whatsoever, there are no requirements for protection.
Accessible attics with permanent stairs or built-in ladders require board protection throughout the attic on floors and walls/ceilings.  In accessible attics without permanent ladders or stairs, such protection is only required within 6 feet of the access opening.  In attics less than 30-in. high, no access is required.  Where there is no access whatsoever, there are no requirements for protection.

For more on electrical rough wiring, visit the JLC Field Guide