I use a coat hanger to fish electrical cable through walls, and for longer runs, bare copper wire.
Cut your cable at an angle so its end is tapered instead of blunt. Leave the wire nearest the point of the angle cut about 3 in. longer than the other two wires. Straighten the coat hanger and make a small loop at the end.
Feed the wire through the loop and wrap it around the coat hanger. Start your tape wrap on the cable, above the splice. Tightly wrap the tape spirally until you’ve wrapped down onto the coat hanger. Each consecutive wrap overlaps the previous one, reducing the possibility that a tape edge will snag on something when you’re pulling it past obstructions.
Copper wire isn’t as stiff as a coat hanger, so it’s likely to pull free of the coat hanger–style splice. If you’re using a bare copper wire as your fishing tool, use a Western Union splice. Start with two L’s, then wrap each wire around the other without looping them back on themselves. The taping step is the same for both methods. — Al Hildenbrand, Master Electrician