Large projects require power cable pullers to get the job done quickly, efficiently and with minimal physical labor. The equipment’s basic components are the frame, power source, capstan, pulling rope and mechanism that rotates the capstan. A broad range of sizes and pulling capacities are available.
While the wire-pulling process is straightforward and hasn’t significantly changed over the years, pulling equipment has continuously evolved, along with accessories such as cable feeders, support and feeding sheaves, pulling grips, remote foot controls and lubricants. Recent developments include force gauges that measure rope tension during pulls as well as pulling calculators that help calculate pulling loads and recommend the capacity of cable puller that should be used. For instance, low-voltage copper and fiber optic cable requires different handling than power cable (see sidebar).
Cable pullers and accessories
Having the right pulling equipment on the job can save thousands of dollars in time spent during cable installations, said Tim Bardin, director, equipment products for Southwire, Carrollton, Ga.
“Manual pullers rarely are seen in the field today,” he said. “Electrical contractors across the United States have adopted power cable pullers as a standard. Over the past 10-plus years, the adoption rate of contractors moving to high-speed, lightweight cable pullers for their moderate to light tension cable pulls has been tremendous. With a 2-minute setup time and the high pulling speeds of electric cable pullers, electricians save time on installations and reduce physical fatigue caused by using manual or large, bulky cable pullers.”
Southwire offers three industrial- rated Maxis cable puller models and a cable feeder to assist in feeding on heavy conductor installations. Capacity ratings are based on the tension needed to successfully pull the conductors through the raceway or conduit. Ratings are 3,000, 6,000 and 10,000 pounds.
Last year, Southwire introduced the XD10 Extreme Duty puller.
“By incorporating a gear-reduced hand crank to articulate the pivoting motion of the puller, we have reduced the need for excessive lifting during the setup process,” Bardin said. “In addition, the capstan design significantly reduces the exertion needed by the user on the pull rope. This allows the puller to do the work which reduces user fatigue and strains.”
This puller is built to handle pulling conditions up to 10,000 pounds of rope tension. Its power train handles a maximum continuous load of 7,000 pounds at 8 feet per minute with peak performance up to 10,000 pounds.
Bardin said the cable feeder is one of the best and often overlooked accessories.
“A feeder can help manage the conductors by pulling the wire from the spools to the conduit or cable tray,” he said. “Feeders aid the pulling process by reducing the back tension from wire spools to the raceway and even as a pulling assist in cable tray installations.”
Greenlee offers five models that include lightweight equipment with pulling forces up to 2,300 pounds; midsize cable pullers with up to 6,500 pounds of pulling force; and heavy-duty pullers that have the capacity to pull up to 10,000 pounds, according to Product Manager Sumeet Pujari.
The Greenlee G3 Tugger pulls continuous loads up to 1,200 pounds and can pull up to 1,000 pounds at high speeds. The unit is UL- and CUL-rated for pulls up to 2,000 pounds (intermittent). With no load, it pulls at 97 feet per minute at high speed and 41 feet per minute at low speed. Quick-disconnect pins enable users to quickly and easily change tail length, pull direction and pull angles. It also attaches to a truck hitch for outdoor pulls.
[SB]Accessories, such as cable feeders were introduced to assist in cable-tray pulling to allow for easier, safer cable pulling. Products include medium-duty cable rollers, heavy-duty cable rollers and quick-adjust sheave trays.
“As cable trays continue to be utilized more and more [in commercial and industrial construction], Greenlee has continued to create safe and efficient tools to pull electrical wire through them,” Pujari said. “Our new cable tray feeder is an over-tray mounted, motorized cable-tray feeding device that allows users to safely pull electrical cables without using their hands.
“The over-tray mounting system [has] a patented design utilizing a ratchet strap that safely and securely mounts to the tray. The feeder can be operated with a handheld pendant that controls the feeder from as far as 8 feet away. An automatic force limiter stalls out to prevent damage to cable insulation,” he said.
Also available are accessories that connect rope to cable, which will allow the rope and cable to twist separately inside the conduit; one-time use grips that will help with pulling head setup in less than 2 minutes; basket-type, reusable grips rating from 700 to 9,600 pounds; multiple types of swivels that have a rating from 2,500–25,000 pounds; and jack stands for holding cable reels during pulling cable feeders.
Pulling rope and lubricants
Pulling rope is an essential component for pulling cable, and only rope rated for this use should be employed.
Pujari said nylon polyester double-braided ropes are available in thicknesses of 1/2-, 3/8-, 9/16- and 7/8-inch and in lengths of 300, 600 and 1,200 feet.
“It is recommended that, when performing a pull, that pulling rope has a safety factor up to four-to-one as compared to the puller being used,” he said.
Bardin said double-braided, polyester pulling rope has been the industry standard for many years.
“Depending on the diameter, these pulling ropes range in breaking strength from 14,000 to 32,000 pounds,” he said. “Double-braided pulling rope is abrasion- resistant and has an elongation rate up to 10 percent.”
Southwire offers a pulling rope that has a breaking strength of 32,000 pounds at a 9/16-inch diameter with only a 3 percent elongation rating. This rope reduces pulling tensions and reduces the amount of rope stretch during a pull. With less tension and stretch, typical pulling times decrease by 15 percent or more.
Pulling lubricants make pulls easier and can reduce the force needed to make a pull. However, some types of wire are designated not to be used with lubricants.
Pujari said pulling lubricants reduce the friction coefficient when pulling cable through conduit. Greenlee offers lubricants in a cream, gel and winter gel with a freezing point of –25°F.
“It is important to know what the wire manufacturer recommends prior to installation,” Bardin said. “Some wire that does not require lubrication actually pulls easier than conventional types of wire that require lubricants. When a lubricant is recommended, it is important that it is evenly applied on the wire throughout the cable installation.”
Calculators and tensiometers
Technology is making cable pulling easier and more efficient.
“New to the market is a digital force gauge, which is a tensiometer that measures the tension of rope during a cable pull,” Pujari said. “The G-Series Smart Pull gauge provides electricians in the field with information regarding pulling force, speed and distance to enable pulls within the limits established to prevent damage to the cable. The gauge gives an early warning to the end-user to prevent exceeding the tension on the cable. Stored data is a liability protection for the contractor. This will help justify all the pulls were done right to the building owner. This will prevent rework for the customer. Gauge accuracy is plus or minus 5 percent.”
Pull calculators help select the right cable puller for an application. Southwire’s is available on the company’s website and the iTunes Store. Greenlee’s is on the iTunes Store and Google Play Store.
“Southwire’s cable pull calculator not only calculates continuous pulling loads and sidewall tensions but also recommends which capacity cable puller to use for the pull,” Bardin said. “Using the calculator prior to constructing a raceway will aid in its design, helping mitigate common pitfalls that cause excessive pulling tensions.”
Greenlee’s PullCalc App pulling calculator finds the approximate pull force needed to install electrical cable inside conduit and helps select the correct equipment to make the installation.
“The pull force is calculated by ‘legs’—straight runs of conduit followed by a bend,” Pujari said. “The force needed for each leg is found when app users enter information regarding the materials being used for the cable installation into calculator.”