Fishing Wiring Through Walls
Also see:This is page 2 of this article. Go back to Finding an Electrical Source for help finding a source for your new outlet.
Cut drywall and gypsum board plaster using a drywall saw. Cut holes in lath plaster using a reciprocating or keyhole saw. See Repairing Large Holes in Ceilings or Repair Larger Holes in Walls for help with plaster and drywall repairs after the new cable is run.
Cut the Necessary Holes to Run the New Cable
Determine inside of which walls and ceilings the cable must be run. For example, with a new ceiling fixture using a source from an existing wall receptacle, the cable will have to be run inside the wall cavity, through the wall header and into the ceiling cavity to the new fixture. Or if you are using a receptacle on an upper floor to serve a ceiling fixture below, the cable would have to be run through the sole plate and flooring and into the ceiling cavity below.
Mark and cut the holes for the new outlet boxes using the box as a template. Before installing the box use the hole to aid in running the new cable. Decide where it will be necessary to cut holes in walls and ceilings to allow for boring holes in the framing. Mark and cut a 6 inch wide by 12 inch long rectangle on the wall material at ceilings to allow access to the header. Mark and cut a 6 by 12 inch hole about an inch above baseboards to bore holes in the sole plate and flooring. These are the minimum sized opening needed to run the cable, if necessary, cut away extra wall material to allow room for reaching into the wall or ceiling cavity to bore holes and reach cable.
Bore the holes for the cable in the framing using a high torque drill or hand auger and a ¾ inch bit for NM cable and 1 inch for armored cable or greenfield.
Fishing the Cable Through Walls and Ceilings
Thread an electrician's fish tape through the first framing hole and to the electrical source. You will need to remove the outlet box at the source to access the end of the fish tape. Tape several inches of the new cable to the fish tape keeping the bundle small enough to pass through the framing hole. Tape the end of the cable down so it doesn't catch as it enters the hole.
Pull the cable into the wall cavity and through the first framing hole. Pull some excess cable into the room and then cut the cable free from the fish tape. Move to the next opening in the run. Fish the tape through the framing hole and wall to reach the new cable. Tape the end of the cable to the fish tape and pull it through to the next opening. Pull extra cable through and cut the it free from the fish tape and move to the next opening. Use this method at each point in the run.
Tips for Fishing the Cable
If the fish tape hits an obstruction inside the wall turn the the rolled coil one way or the other and try to push past the obstacle. Because the fish tape is a rigid, flat wire, it is bowed in the direction of the coil. Turning the coil will turn the end of the tape in the same direction.
It can be a tricky process to make all the necessary turns in the cable. Cut more holes in the wall and ceiling covering if necessary to reach the cable and pull it by hand. Pull enough extra cable on both ends of the new run to allow for splicing, etc. About 12 inches is usually enough.
Connect All New Wiring
Install a cable clamp in one of the holes in the new outlet box and pull the cable through it. Tighten the clamp leaving about 10 inches of cable hanging from the box. Install the box in the wall opening. Connect the wires at both ends of the run. See Wire Splicing and Installing Receptacles and Switches for help. When all new wiring is complete turn the power on to the circuit. Test to be sure that all the wiring is correct. Test any receptacles with a receptacle analyzer and switch lights on and off. Shut the power off to the circuit again and fasten all receptacles, fixtures and cover plates tightly in place. Turn the power back on to the circuit.
Go back to Finding an Electrical Source for help finding a source for your new outlet.
