EZSMART Corporation, ESA/ECRA #7012690 , North York , Ontario
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A fish tape is the go-to tool for routing wire through finished walls, conduit, and ceiling spaces without opening up drywall. Using it correctly is a skill that saves hours of frustration on every rough-in or retrofit job — and learning it properly prevents the most common mistakes that kink tapes, damage conductors, and leave wires stuck halfway through a wall cavity.
A fish tape is a long, flexible steel or fibreglass ribbon wound on a reel, used to pull electrical wire and cable through walls, conduit runs, and ceiling plenums. The tape is fed through the pathway first, then the wire is attached to the tape’s hook end and pulled back through. Professional electricians use fish tapes on nearly every retrofit job — understanding the technique used makes planning and executing electrical work in finished spaces much faster.
Steel fish tapes (most common, 25–100 feet) are rigid enough to push through bends in conduit and down wall cavities with some directional control. They are the standard choice for conduit runs and short wall pulls. Fibreglass fish tapes are non-conductive — essential when pulling wire in live conduit or in environments where accidental contact with energized conductors is a risk. Steel tapes conduct electricity and must never be used in or near live panels or live conduit without first confirming the circuits are off.
Flat steel tapes (typical for in-wall use) navigate wall cavities and around insulation better than round tapes. Round steel tapes are stiffer and better for longer conduit runs where you need to push the tape around multiple bends. For conduit work specifically, see our guide on how to pull wire through a conduit easily — conduit pulls have their own techniques (lube, pull lines, reverse feeding) that differ from open-cavity work.
Map the path before inserting the tape. Know where the tape needs to come out, what obstacles (fire blocking, headers, insulation) are in the path, and where you will make your access holes. In a wood-frame wall, horizontal fire blocking at mid-height is the most common obstacle — you may need a second access point above or below it, or to drill through it with an extended bit.
Identify and turn off any circuits in the wall you are fishing through. Use a non-contact voltage tester to confirm the space is dead. In Ontario, working inside a wall cavity near live conductors without confirming they are de-energized violates OESC safety requirements, and the Electrical Safety Authority (ESA) considers it a safety hazard regardless of whether the fish tape is steel or fibreglass.
Lubricate the tape before feeding it through conduit (use wire pulling lubricant, not petroleum-based products that can damage wire jacket). For open wall cavities, lubrication is not needed. Unspool just enough tape from the reel to reach the destination — loose tape on the floor creates tangles and kinks.
Insert the tape at the starting point — typically from an outlet box or a hole cut in the drywall — and feed it toward the destination. The tape’s natural curve (it bends slightly from being wound on the reel) helps guide it in a direction: rotate the reel handle to steer the curved tip as you feed. If the tape stops moving, do not force it. Forcing a tape that is caught on an obstruction kinks the tape and can damage wire jacket on existing conductors in the wall. Withdraw slightly, rotate the reel to change the tip orientation, and try again.
For vertical runs (fishing from an outlet to a switch above, or from a panel up to a ceiling box), feed the tape from the lower point upward when possible — gravity assists in keeping the tape from folding back. When fishing from top to bottom, attach a small weight (a hex nut or a fishing sinker) to the tape end to help it drop through the cavity rather than curling back on itself.
When the tape reaches the destination box, have a second person at that end listen for the tap of the tape end and watch for it to emerge. A flexible bead-chain leader attached to the hook end of the tape makes it easier to grab once it appears. See our guide on how to fish wire through insulation for wall cavities with blown-in or batt insulation, which require different technique because the insulation grabs and bunches against the tape end.
Once the tape is through, strip the jacket back about 6 inches on the cable you are pulling. Fold the individual conductors back over the cable jacket and thread them through the hook on the fish tape end, then wrap the conductors tightly with electrical tape, creating a smooth bullet-shaped connection with no sharp edges or protruding loops. A poorly wrapped connection catches on framing, drywall edges, and conduit fittings as it is pulled through, dramatically increasing pull friction and risk of tearing the tape hook.
Use only enough tape to make the connection neat and smooth — excess tape bulk increases the size of the connection and makes it harder to pull through tight spaces. For multi-conductor cables like NMD90 (Romex-equivalent), wrap the entire folded section tightly to keep it from splaying as it is pulled through.
Two-person pulls are far more efficient: one person pulls the tape reel steadily and slowly, while the other feeds wire from the cable spool or box, keeping constant gentle forward pressure on the cable so it does not drag. Jerky, fast pulls snap tape hooks, strip tape-wire connections, and can pull insulation off conductors in tight bends. Smooth, steady tension at 2–5 mph is the correct pace for most residential pulls.
If the pull stalls, stop immediately. Check whether the connection has come undone (tape returned, wire stayed). Check whether the wire is caught on an edge inside the wall. Do not increase pull force past the point where you feel significant resistance — bends in the path increase friction exponentially, and a force that would feel reasonable in a straight run can snap a steel tape in a tight bend. Wire pulling lubricant applied at the entry point, fed along the cable as it enters the wall, greatly reduces friction in tight runs.
If a tape breaks or becomes stuck and cannot be retrieved by pulling, the standard recovery technique is to feed a second tape in from the other direction and try to snag and free the stuck tape. A telescoping magnet can retrieve a steel tape that is visible through the destination hole. In a worst case, a small exploratory drywall cut at the point of obstruction lets you clear the blockage and repair a small patch rather than running a new tape from scratch. For a stuck tape in conduit, try rotating the stuck tape as you pull — the rotation changes the contact angle on bends and often breaks the friction lock.
For very long runs in conduit, many electricians prefer a pull string (nylon cord or Greenlee pull line) fed with a blower or vacuum method rather than a steel fish tape. The tape is excellent for shorter runs under 50 feet and for navigating open wall cavities where a pull string has nothing to grip. For runs over 50 feet through conduit with multiple bends, a fish tape can be too short or too stiff, and a pull line blown through with a shop vac is faster. See our guides on electrical conduit types and uses and basic electrical tools every homeowner needs for context on when a fish tape belongs in your toolkit versus a pull string or other method.
The single most common fish tape mistake we see from homeowners attempting their own retrofit wiring is using a tape that is too short. A 25-foot tape is fine for a dedicated outlet across one wall, but anything involving a run from the basement panel up to a first-floor outlet box easily exceeds 30–40 feet once you account for the actual path (not the straight-line distance). We carry a 50-foot and a 100-foot tape on every job. The second most common mistake is not securing the wire-to-tape connection tightly enough — if it unwraps mid-pull, you have to start over from the beginning. Take two minutes to make a clean, firm tape-wrapped connection before starting the pull. It is the one step that determines whether the pull takes five minutes or forty-five. For all work inside a panel or involving a new branch circuit, an ESA permit is required — fish tape work is generally the easy part compared to making up the connections at each end safely and correctly.
Need a licensed electrician to run wire through your finished walls or conduit in the GTA? Call us at 416-838-9006 or visit our contact page — we will get back to you the same day.
Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp
