How to Use a Fish Tape for Wiring

How to Use a Fish Tape for Wiring

A fish tape is a long, flexible metal or fiberglass ribbon wound on a reel, used to pull electrical cables through walls, conduits, and ceiling spaces. It is one of the most essential tools for running wire without tearing open finished walls. Using a fish tape effectively takes some technique, especially when navigating around insulation, fire blocks, or bends in a wall cavity.

Types of Fish Tape

• Steel fish tape — most common, stiff enough to push through long runs, conducts electricity so keep it away from live circuits
• Fiberglass fish tape — non-conductive, preferred when working near energized wiring
• Flat nylon fish tape — flexible and easy to feed around bends, better for short runs through conduit

Basic Technique: Running Wire Through a Wall

1. Determine the entry and exit points — typically two outlet boxes, one above and one below, with the fish tape traveling through the wall cavity between them
2. Turn off power to any circuits in the area and verify with a non-contact voltage tester
3. Remove the outlet covers and boxes at both locations to create access
4. Feed the fish tape from one opening, guiding it toward the other. The hook end of the tape helps catch on edges as you push it through
5. When the tape tip reaches the exit point, attach the cable to the hook end — strip the cable sheath back several inches, fold the conductors back against the cable, and tape them tightly with electrical tape to create a smooth nose that will not snag
6. Pull the fish tape back through the wall from the entry point while a helper feeds the cable from the exit end
7. Pull steadily — jerking can cause the tape to separate from the cable

Tips for Navigating Obstacles

• Fire blocks — horizontal 2×4 blocking inside walls stops a fish tape cold. Use a drill with a long bit to bore through the block, then continue fishing
• Insulation — in exterior walls, dense insulation resists the tape. A fiberglass tape feeds more easily through insulation than steel
• Bends and corners — flex the tape at the tip slightly so it tends to curve toward the exit opening
• Two tapes — if access is available from both ends, feed two tapes toward each other. When they cross and catch, one can pull the other through

Running Wire Through Conduit

For conduit runs, a flat nylon fish tape or a wire-pulling lubricant makes the job easier. Feed the tape through the conduit, attach the cable, and pull from the other end. For long conduit runs with multiple bends, use pulling lubricant generously to reduce friction.

EZSMART runs wiring through finished walls and conduit systems for additions, renovations, and upgrades across Ontario. Contact us if your project requires fishing wire through tight or inaccessible spaces.

Amir Azimipour

Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp