When you’re moving wires around in sub-floors, ceilings and walls there’s no tool so vital as your fish tape, yet wire fishing takes subtlety and skill.
Too often a regulation cable pull turns into a nightmare because the correct procedures are not followed right from the beginning. You can’t simply twist a wire around a fishtape wireway and expect good things to happen. At the moment of greatest friction the wrap will fall apart, and this is nearly always the result of poor wraps, improper wire pulling methods, or a failure to understand the challenges of the route.
There’s no point pretending that after a complex wire pull there’s not a big temptation to apply brute force to a final snag instead of laboriously pulling out a fibre optic camera and going through the process of trying to assess exactly what’s going on with the run.
There are a number of things you need to get right from the get-go. First, don’t just mash the fishtape through the wireway. Doing so puts kinks in the tape and makes it difficult to pull the wire and this increased friction means greater chance of pull failure. Second, put some wire lubrication on the first few inches of the tape. This will help it slide over the edges of fittings and around inevitable corners.
There are 3 important rules in wire pulling. For a start you want to make sure your wiring does not exceed the wireway fill specified by the NEC. You also want to use the correct wireway cutting, deburring, and assembly techniques. This will eliminate many of the obstructions that make pulls hard to complete. And you must also be sure to pull the wires only after you complete the wireway. This will save you time and prevent damage to the wiring.
A common mistake is to wrap all the conductors into the fishtape hook. This makes one big knot that will likely come apart; or even get stuck so you can’t move it either direction. Remember to fasten one conductor around the fishtape hook. Don’t tape the joints individually. Tape over the open end of the fishtape hook, then tape the whole assembly.
With one person pushing and another pulling, you should be able to pull the wires through. The person who is pushing should smear lubricant on the wires as they enter the wireway, until the run is well underway. You may need to use needle nose pliers to get the end of the fishtape out.
These techniques ensure an easy pull for most sizes of wire. Unless you are pulling extremely large conductors, you shouldn’t need to use anything other than elbow grease or a good fishtape puller to complete the pull. Sometimes things don’t work out with a wire pull. There will be one corner too many, or some invisible snag. If you can’t get the fishtape through, even though you have been very careful with all aspects of the pull there are 3 options available.
Firstly, and often successfully on shorter wire pulls, you pull the tape back out and cover the hook with phasing tape; then coat the phasing tape with lubricant. But what if after a tough pull you’re almost there and don’t want to pull the tape all the way back out? In this case you can run a second tape in from the other end and manipulate it to connect with the first tape.
A third option is to make some loops of stiff wire and tape them in place. Then, let the first tape grab on to one of these. Now, attach the wire to the fishtape. For the best chance of pulling it through you should strip 15cm of insulation off each conductor and fasten one conductor to another, by tightly wrapping the first conductor around the second.
#sen.news
