Electrical contractors use pulling rope - from twines and twisted poly on the low end to polyester composite double braids in diameters up to 1 1/2 inches for heavy, multi-cable installations - to pull cable and heavy wire through conduit.
Only synthetic products are used in this application because natural fiber ropes are heavy, absorb and retain water, and have coarse, abrasive surfaces.
Nylon rope should never be used to pull cable - it stretches and can snap back like a rubber band and cause serious injury.
We strongly suggest you make it a point to know what kind of rope you're using, inspect it prior to every use, and if it starts to show signs of wear, replace it.
Double braided polyester composite rope is recommended for heavy pulls, especially where multiple cables are being installed. Most equipment manufacturers specify that the rope used should have very low stretch, and that its tensile strength be matched to the cable puller’s maximum pulling force, using a minimum 4:1 safety factor. So a cable tugger with a maximum pulling force of 8000 lbs. should use a pulling rope with a breaking strength of 32,000 lbs or more.
Twisted polypropylene rope can be used to pull heavier ropes, or sometimes to pull cable. Its main virtues are that it's inexpensive, light in weight, has a slippery surface, and has excellent dielectric properties. The downsides are that (a) it has some stretch - not as much as nylon, but more than polyester, and (b) it has a very low melt point and can start to melt and stick to surfaces it touches when frictional heat builds up.
Woven polyester tapes are offered for sale just for measuring and pulling. Woven polyester tapes are a good step up from poly rope. The stretch is very low and the strength high. Available features include sequential footage markings for distance measurement and a detectable version with woven-in tracer wires.
Polypropylene twines similar to those available for tie-downs at home improvement stores are used with power fishing systems. Electrical contractors use these poly twines only to pull heavier rope through conduit – not to pull cable. After being blown or vacuumed through the conduit, polypropylene twines are sometimes left in place for future use.
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