How to run cables in drywall?
When adding new circuits in existing drywall pros will cut a hole where the box goes.
Next use special drill bits to drill up or down depending on the direction of the wire pull, drilling up to get through any fire breaks going to the ceiling then drilling through the top plate, or to go down or through the bottom plate going to the crawl space.
The side of the hole is the size for an old work box.
The special drill bits are long flexible screw end spade bits the screw tip helps pull the bit into the work. A trick to center the bit to keep it 1-1/4” away from the plate edge is using a tennis ball on the shaft. (This can be difficult on exterior walls with insulation, in some cases another hole is cut and patched usually high on the wall) to get the needed holes to snake the cable in the wall.
Several methods to run the wire in the walls include:
“fish rods” are used these are normally thin fiberglass rods that we feed up to the hole and use to pull the cable down.
A pull string is commonly used dropped through the top hole with a tubular lead weight (think fishing) I mark the string for 8’ so I know the string made it all the way down. If it hangs up pulling up and letting it drop will tunnel through fiberglass insulation. Then use a coat hanger to reach in through the hole and grab the string.
The last method is usually on interior walls or no insulation straighten the cable and stuff it in the hole and feed it down grabbing the cable from the hole with a coat hanger.
Inside the wall no staples are required when pulling nm (Romex) or flex (mc,ac or flex able conduit) in a finished wall.
These are the methods I normally use.