Whether you are on a residential or industrial project, bending conduit is going to be required. For small jobs, hand benders are sufficient; for larger projects, there are multiple options.
“The main benefit of hand benders is they are easy to carry around at the job site,” said Jae Lee, project manager—bending, Greenlee, Rockford, Ill. “However, for larger sizes of conduit, they require more force to operate, which for large jobs, becomes a tedious and heavily manual process that can impact bend uniformity. The development of mechanical and electrical benders was an alternative to address electrician’s bending needs.”
Historically, there are two basic types of hand benders. Benfield benders are made of iron, and markings on the heads provide reference points for bend angles. Gardner-style benders are made of die-cast aluminum and have built-in spirit levels at the 45-degree and 90-degree positions.
To improve repeatability of bends, various improvements have been made to help users achieve consistent bend angles. Ductile iron is strong and durable while aluminum is lightweight and easy to handle, said Jason Schaper, product manager, Ideal Industries, Sycamore, Ill. They have rugged, steel constructed handles for long-lasting durability, as well as an enamel finish to resist corrosion.
“The best benders will have raised markings cast into the bender head on both sides for easy visibility to ensure accurate bends,” Schaper said. “A popular innovation has been a boot that Ideal introduced to fit on the end of a bender handle. The grooved surface provides stability and leverage when doing offset bends on smooth floors and surfaces.”
In making hand bends, the type of conduit is an essential consideration. Schaper said the main difference between EMT and IMC is that IMC has a thicker wall.
“Therefore, when bending IMC, an individual would use a ¼-inch larger bender to make the equivalent bends,” he said. “For example, a ¾-inch IMC conduit would use a bender designed to accommodate a 1-inch EMT conduit.”
Rack-A-Tiers, Victoria, B.C., Canada, has a Hoppy Bender with a stop attached to the head to create exact and repeatable bends, said Ken MacLachlan, president of Rack-A-Tiers.
Simplified multipliers are engraved into the bender for placing the stop prior to making offset bends and four-point saddles. There are 22.5- and 45-degree marks engraved into the bender for placement of conduit bend marks as well as standard degree marks for stop placement used together for bending three-point saddles without reversing the conduit in the shoe. A reference chart for locating bend marks is attached to the handle.
Tanner Hansen, bending product manager at Southwire Tools and Equipment, Carrollton, Ga., said some of the largest innovations in hand bending have been made in product adjacencies. Increasing the functionality and accuracy of something as little as a level can increase efficiency for the user.
Mechanical and hydraulic benders
Mechanical benders are a step up from hand benders. Muscle power still provides the force for making bends, but bender components are mounted on a cart or carriage for easily rolling around job sites. Interchangeable shoes are used for various conduit types and sizes.
Hydraulic benders are often used for rigid conduit or for conduits in sizes from 2½ to 5 inches, which are too large for electric benders. They make smooth, round bends without conduit squeeze or bulge and without splitting pipe seams. Power for hydraulic pumps is provided manually or by electric pump motors.
For higher-production bending, electrical benders are available in a variety of sizes and models. Higher-end products have convenience features, such as adjustable operating positions, programmable capabilities for making accurate repeat bends at the same angles, remote pendant controls, and the ability to calculate layout measurements before bending work starts. There also are models with built-in combination shoes that will bend all 1- to 2-inch rigid, EMT and IMC conduit without additional accessories.
Hansen said manufacturers are focusing on improving bending ergonomics.
“These changes make the monotonous task of bending conduit easier on the contractor’s body and help to reduce fatigue and increase output,” he said. “A byproduct of this hyper focus on ergonomics means less physical wear and tear on the operator. For example, bending IMC and GRC requires more breaking strength than EMT, making it more important for contractors to operate in a way that promotes better body mechanics. Conventional conduit bending is done with hand benders on the ground, requiring immense physical interaction. Going to a purpose-built bending cart or power bender for these thicker-walled conduits help reduce the stress put on the user’s body.”
Southwire Tools manufactures hand benders for EMT and IMC, manual benders, mechanical benders, table benders, power benders and PVC heaters.
Greenlee’s Lee said safety is the most important bender feature at his company.
“All Greenlee electrical benders are, among other safety designs, UL-certified to ensure the safety of the electricians,” he said. “Also, the electrical benders can protect themselves from extreme conditions such as too high or too low voltage by shutting down.”
The major improvement to Greenlee benders is the easy interface between the electricians and the bender.
“They are designed to maximize efficiency by improving the interface of the bender,” Lee said. “As an example, we have combined multiple shoe groups to a one-shoe design that bends rigid, IMC and EMT conduit. This eliminates the need to change the shoe and roller supports. It also reduces the number of loose pieces an operator needs to complete a job. We also have a patented split squeeze roller design that eliminates change over between IMC and EMT conduit.
“Electrical smart benders have a digital angle display on the pendant, providing the operator visibility of the current bend angle from any position. The smart benders calculate the conduit bend marks and input the conduit spring-back values, which minimize human error and rework. Last, but not least, smart benders can display conduit designs from the BIM 3-D model and guide electricians step by step on how to make the conduits from the 3-D model. This feature assists electricians to perform quality bends to match prints,” he said.
Rigid and IMC conduit share the same shoe groove, Lee said, but EMT conduit has different shoe grooves.
“Greenlee’s electrical benders include squeeze rollers that provide pressure when bending EMT and IMC,” Lee said. “Therefore, it is important to use the specified squeeze rollers for the appropriate conduit type, because if the wrong pressure is applied, the conduit can wrinkle. Two of our benders have a patented squeeze roller design to eliminate the need for multiple types of squeeze rollers. The split roller design applies the right amount of pressure to both IMC and EMT conduit.”
Prior to bending conduit, ensure the inside weldment is away from the bend’s inner radius. Failure to apply this step—incorrect placement of the weldment—may result in the conduit wrinkling and ultimately leading to failing the inspection. If conduit fails inspection, it has to be removed and replaced with new conduit.
When bending conduit, spring-back is always a factor.
“There are formulas and multipliers that electricians use to account for spring-back when bending conduit,” Lee said. “Greenlee offers a reference spring-back chart on our benders, which provides guidance when accounting for spring back in effort to produce accurate bends. This eliminates rework, which occurs when conduit is over- or underbent.”
Greenlee makes a variety of benders including hand benders, mechanical benders, electrical benders, hydraulic benders, programmable benders, bending stations and PVC heaters.
Carts and mobile bending stations
Mounting a manual or hydraulic bender on a cart makes the bender easier to move around the job site and provides conduit storage space. Bend carts have evolved into mobile bending stations, which consolidate everything needed to bend and thread pipe.
For example, Greenlee’s Workhorse mobile bending and threading station’s workspace is at an optimal, ergonomic height that helps reduce the risk of musculoskeletal disorders. It has multiple storage areas at various heights and locking storage space. A built-in conduit pipe support used in conjunction with the bend tray checker allows for quick verification of 90-degree bends and conduit measurements. The work station can accommodate several pipe threader models.
Bending PVC conduit
Demand for PVC conduit is growing for certain applications, Southwire’s Hansen said. The most common practice for bending PVC conduit is heating the pipe and bending it over a jig. PVC heat boxes and blankets are used to evenly heat the conduit.
Lee said heat blankets and boxes help electricians bend uncoated PVC. Once the necessary amount of heat is applied, the uncoated PVC becomes flexible for bending. Pipe plugs on each end of the conduit speed up the heating process. Once uncoated PVC is bent to the right shape, electricians can wait until cools or apply a wet towel to reharden the pipe.
Rack-A-Tiers offers a cold-bending device: a spring inserted inside the conduit to hold its shape while the conduit is manually bent.