Cool Tools: Power Cable Pullers
Published: November 2008
Power cable pullers take most of the hard physical work out of pulling power cable through conduit. These tools make the job faster and, when used correctly, safer than working with old-fashioned manual pullers or makeshift pulling methods.
Power cable-pulling equipment is available in a variety of sizes with pulling capabilities ranging from 1,000 to 8,000 pounds. Basic components of most power pulling tools include the frame, power source, the capstan that pulls rope and wire, the mechanism that turns the capstan, and the pulling rope.
Most pulling equipment is used for electrical cable. Datacom installations usually are made beneath floors, above ceilings in cable trays, and in other locations where a pull is not necessary. Characteristics of datacom cables also require special handling and can be damaged without careful handling.
“Cable pullers used by electricians haven’t changed much over the last few years,” said Jim Eisele, Greenlee senior product manager. “From Greenlee’s perspective, there is a trend among electrical contractors to use pullers selected to meet individual applications.”
“For a time, it seemed contractors would bring their biggest pullers to the job,” Eisele said. “They didn’t want to get caught short, and having a powerful puller meant they could handle anything the job required. Now we’re seeing smaller units that are easier to set up and move around the job site.”
Eisele said several types of support equipment are changing the way many pulls are made.
“Cable feeders aren’t new, but they are very useful on large jobs where physically pulling cable off reels can be very strenuous work,” Eisele said. “A project may have four reels of cable that require three or four people to feed cable. A cable feeder is a power tool that lets one person do the job.”
Just introduced is the PF8 pull force estimator for calculating pulling force required for a job. Eisele said the Microsoft Excel-based program lets the contractor plan pulls and decide what pullers will be needed, matching a specific puller to a specific job.
Gardner Bender has learned that size, mobility, versatility and ease of use are important considerations for the user, and cable pullers are being designed to meet these needs, said Christian Coulis, capital equipment product manager. Strength and durability also are important attributes contractors want in cable pullers, Coulis said.
Job conditions dictate which puller is best for a project.
“The size of the conduit, type and size of the cable being pulled, total number and degrees of vertical or horizontal bends and configuration of a pull are the key factors in determining the size of puller that is needed,” Coulis said. “Every job requires multiple pulls, and no two pulls are exactly the same. Most electricians have light- and heavy-duty pullers. Typically, a 2,000-pound puller will be used on 1- to 2-inch conduit, and an 8,000-pound or larger puller can be used on 2- to 6-inch conduit.”
As an example of the versatility of modern pullers, Coulis cites Gardner Bender’s new Mini-Brutus, a collapsible, lightweight, compact puller with an interchangeable motor.
“This 2,000-pound cable puller can be fully extended to 9 feet, 8 inches or collapsed to 44 inches to be easily rolled throughout the job site,” Coulis said. “This unit can also be set up and operated by one person, saving time and resources on the job site, and its versatility enables the contractor to use the power drive as a pipe threader or to use a pipe threader as the drive motor.”
Coulis said the most frequently used pulling accessories are lubricants to reduce friction between the cable and conduit around bends, hook sheaves used in small work areas or in configurations where positioning a cable puller is difficult, and pulling grips for making the connection between the cable and the pulling rope.
“Pulling fluids or lubricants are very important accessories in many pulling jobs,” Coulis said. “The use of lubricant will decrease the friction between the cable and conduit by nearly 50 percent, resulting in faster, safer pulls.”
The cable puller lubricating system, a relatively new accessory, sprays lubricant onto all sides of cable prior to pulling.
“It makes the pulling task easier, more productive and safer,” Eisele said. Paul Pothier, Maxis director of marketing, said lubricants are an important aid to pulling. They make the pull easier and protect the cable and inside of the conduit.
“However, with the introduction of the no-lube or prelube wire, there is no need for pulling fluids,” he said. “We have done extensive testing with our pullers and have found that it is easier to use no-lube wire.”
Pothier said no-lube wire isn’t messy like lubrication systems and is easier to use.
Cable designed to be installed without lubricants is a relatively new development, and many in the industry are evaluating its use.
Pothier said small, motorized pullers are so efficient and quick to set up that there should be no reason to hand pull or use manual pullers, especially if there is a risk of physical injury.
Pothier said recent trends show power pullers are replacing manual equipment for more pulling applications, portable power cable pullers have increased in capacity and strength, and high-strength pullers have become easier to set up and can pull at faster speeds.
“Lightweight portables are easy to pick up and move from place to place within a building,” Pothier said. “Heavy-duty pullers are carried on portable carts to facilitate movement. For heavy pulls, the puller is anchored into position and used with pulleys. National electrical codes determine specifications for pulling capabilities, and 3,000- to 4,000-pound pullers—the Maxis Pull-It 3000x is a good example—are the most commonly used and generally will pull No. 8 wire to runs of 350 MCM.”
Regardless of the size of the puller or cable being installed, rope is a key element in the pulling operation. It’s the link between cable puller and cable being pulled. Manufacturers of pulling equipment agree using the right rope is critical to every pulling job.
The rope must be strong enough to sustain the pulling force necessary to bring cable through the conduit. A practical guideline is for rope to have a breaking point four times greater than the maximum pulling force that can be generated by the cable puller. Double-braided composite rope often is preferred because it stretches less and resists heat generated during an installation.
Rope with high stretching characteristics store energy like a stretched rubber band, and a component failure during a pull can unleash this energy, posing serious safety hazards. Polypropylene rope should not be used because it has a low melting point, and friction can cause fibers to melt and stick to the tool’s capstan.
Rope should be inspected for condition, kinks and splices before every pull. Worn or damaged ropes should never be used.
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at firstname.lastname@example.org.