How to Fish Wire Through a Ceiling. When you are doing your own remodeling or electrical repairs, you can sometimes find yourself in difficult situations. Cold, cobweb-filled crawl spaces, damp basements and tight attics are all just a part of the job. Running electric across a ceiling sometimes requires you to enter into the attic--but if you are lucky enough--you may just be able to run the cable across the ceiling without setting foot in insulation. Here is how to fish wire through a ceiling.
Things You'll Need
3/4-inch spade bit
Nonmetallic fish tape
Ruler or straightedge
Electrical wire cable (amount and type dependant on the job)
If you are running the wire across the ceiling for a new light fixture installation, then your first step will be to find the center of the room or the place you want the fixture to be. Once you find it, mark it with a pencil.
Trace your ceiling box at the point where you want the fixture to be installed and use the drywall saw to cut out the access hole.
Visualize where the wire will be coming across the ceiling (from the wall to the box) and make a reference point by marking the wall in that spot. If you are picking up the feed from an existing switch or outlet, then you will want to make your reference point directly above where the wall intersects with the ceiling.
At the point of the wall/ceiling intersection, you are going to use the pencil and the ruler or straightedge to draw the access point where the wire will turn down into the wall. Draw a 2x4 section on the ceiling and a 2x4 section on the wall. They should be intersecting so that it makes an "L."
Next, use the utility knife to cut out the openings in the wall and the ceiling. The top plate should now be exposed. (The top plate is the stud that forms the top of the wall.)
There are two options for getting the wire from the ceiling and into the wall. The first is to bore a hole through the top plate using the drill and 3/4-inch spade bit. This works great, but you will probably have to get into the attic (or make a much larger access hole) to get the drill level while drilling.
The other option is to use the chisel and hammer and carve a notch in the outer side of the top plate for the wire to go through. The notch should be at least 1-inch deep and 3/4 inches wide.
Now, if you are running a new installation and you're not getting the feed from an existing switch or outlet, you will have to cut out the place where you are going to be installing its box. As stated earlier, it should be exactly below the intersecting access point.
Start inserting the fish tape into the ceiling hole where the fixture is going to be installed. Fish it all the way across the ceiling to the intersecting access hole. (If you are running across the studs instead of between them, this could prove to be very difficult, so try to keep your runs following the direction of the studs.)
Once you (or your helper, preferably) grabs onto the fish tape at the intersecting access hole, direct the tape from the ceiling and into the wall.
Keep fishing tape until the end is pulled out of the outlet or switch access hole.
Use the utility knife to slice open the outer insulation jacket on the electrical wire cable (about 4 inches long). Separate the wires within by bending two of them back and leaving one still standing. Bend the lone wire through the loop end of the fish tape and twist it so it won't be pulled off. Then, tightly wrap the electrical wire cable with electrical tape from the point that it is connected to the fish tape to just past where the other wires are bent back. You want everything to be as smooth as possible so nothing gets snagged while pulling the wire.
Begin pulling the fish tape back through the ceiling hole, making sure that you wind it up while reeling it in. This is another area where having a second pair of hands will be helpful. Your helper can guide the wire through the other openings while you concentrate on pulling it through.
Once you pull the wire into your ceiling access hole, bring about 2 or 3 feet through the hole and cut wire from the end of the fish tape. Now you can finish up the installation!
See my article "How to Fish Wire From Below the Floor" (link in Resources below).
Never connect the wire to a power source before fishing it through a ceiling or wall.