Buying the best tool for making electrical connections is not a science but rather a conclusion based on personal preferences, benefits, and budget. Fastening two electric lines together is often best done with a crimper, a common compression tool available in many sizes and styles.

While compression tools have existed almost as long as electric wires, the current crop is engineered with far more consideration for the worker's health, safety, and efficiency than yesteryear's and are worth consideration, even if you have perfectly usable dinosaurs in your tool cabinet or truck.

Choices of types of crimpers-with various permutations of features-are plentiful: die and dieless, handheld, manual power, battery-powered, and remote hydraulic-powered. For connecting wires up to a certain size, operators can use either mechanical or hydraulic crimpers. Hydraulic power is generally used above a particular wire size (sometimes pegged at 250 MCM).

Dieless crimpers and die crimpers

Dieless crimpers are self-contained units that can use any wire and connector within a unit's wire size range. Die crimpers require individual sets of dies for each connector/wire size. Connectors and die sets are color coded to reduce incorrect matches and speed identification of parts. Changing the dies before crimping a different connector size could be bothersome if you are in a hurry or can't easily locate a specific die size. Some die crimpers emboss die index numbers into the connectors (which, typically, carry their own imprint of die index numbers) as the wires are being crimped. This is a nice feature because the matching numbers corroborate that the products are compatible.

Die tools tend to be a little less complicated in construction, less expensive, and lighter than dieless crimpers. Some may believe they make a nicer looking connection than die-less crimpers, which tend to squash the connector.

Tools under each category of crimpers represent what is on the market. Most manufacturers have product offerings in multiple categories.

Manual crimpers

Manual crimpers that rely on brute force may suffice for workers who crimp wires only occasionally. Options for hand-held units include basic die and dieless crimpers and ratchet crimpers. Some manual die-type crimpers have a built-in, multi-nested die wheel that the user spins to select the proper die for the connector being crimped, saving time and eliminating die changeover and possibility of lost dies. Manual models may also include a controlled cycle mechanism that confers control of the crimp onto the tool, rather than the installer, which can improve reliability of the completed crimp.

Thomas & Betts Comfort Crimp Terminal Tool is ergonomically designed to reduce stress in hands and wrists and reduce the risk of carpal tunnel syndrome by, typically, crimping with up to 60 percent less handle force than many other terminal hand tools. Featuring color-coded die nests on both sides of the tool, the Comfort Crimp embosses integrity dots on the top and bottom of the terminals, for easy visual verification of crimps.

FCI Burndy Electrical MR 15, MR 18 and MR 20 series HYTOOLS full-cycle ratchet hand tools feature a full-cycle ratchet mechanism that, unless the emergency release lever is activated, does not allow the handles to be opened until after the full ratcheting cycle is completed, ensuring a completed positive crimp. A narrow nose enables crimping in confined areas.

Panduit Contour Crimp line of terminal crimping tools suitable for various ranges, also featuring a controlled-cycle mechanism that ensures a complete crimp each time, was ergonomically designed to reduce stress in hand and wrist by lowering termination crimp force. Engineered to accommodate all size hands, the tools feature contoured handles and finger grips that facilitate two-handled crimping and a locator that automatically resets to the proper position after each crimp.

ILSCO MT-25 die-less crimp tool, made of cast steel, can be used on both copper and aluminum conductors, up to 250 MCM. The tool features an easy-to-use thumbscrew adjustment for wire size. The narrow design and one movable handle facilitates use in tight spaces. A positive crimp is made when the handle meets the tool body.

Battery and hydraulic crimpers

When a worker in the field must make repetitive crimps throughout the day, it often could be more productive to use battery-operated or hydraulic (electric or manual pump, self-contained or remote) crimpers that save on body wear and tear and, possibly, workers' compensation claims or absenteeism for repetitive stress injuries. (Ergonomics suggests that any repetitive motion requiring force that can be accomplished with mechanical advantage will help keep repetitive motion injuries such as muscle strain in the arms and shoulders in check.)

Power tools are sometimes not only the tools of choice but of necessity. For example, when space limitations disallow placement of a manual tool in a tight location. (To avoid buying for single-project use, contractors can sometimes rent a power tool from another contractor, short term.) Many battery tools are sold to utilities or electrical contractors working on utility-size wires, when the added cost is justified.

While many electrical contractors can get by with a 6-ton hydraulic tool, others-especially those going above 500 MCM copper or 400 MCM aluminum-use larger hydraulic crimpers which also have downward range. Generally, crimpers capable of 12-plus-ton crimping force may be die or dieless battery-powered or hand-held hydraulic or remote hydraulic units.

Huskie Model REC-458 ROBO Crimp, capable of 6-ton output and designed to squeeze commonly used service entrance connectors, lugs, sleeves, H- and C-taps, features a 180-degree swivel head and compact design which could be useful in limited access areas. The unit, which comes with a D3 nest die and accepts a W- or O-type die, as well, features a connector range of #6 - 4/0 Cu/Al for lugs and splices and 4/0 for H-taps. The company also offers Model REC-3510 ROBO CRIMP, its 12-ton compression battery-operated compression tool, which can compress lugs and splices up to 750 MCM Cu/Al. Both models sport a built-in, pre-set 10,000 psi bypass cartridge that audibly kicks out, ensuring a complete compression every time. Other models are also available.

FCI BURNDY Electrical BCT500 hydraulic self-contained, battery-actuated tool, with 6-ton output, features on hand operation for ram advance and retract and an integral 180-degree rotatable latch head design. The tool, which sports a variable speed trigger for easy starting of connector crimps, has a permanent "D3" die groove that also serves as a seat for all "w-" "W-VT-" and "X-" style dies. The company also offers BAT750 hydraulic self-contained, battery-actuated tool with 12-ton output, also featuring one-hand operation for ram advance and retract, that incorporates a constant power (no pulse) microhydraulic pump with 10,000 psi output. The tool comes with Burndy's Y750 tool head, capable of using all "U" style dies, and incorporates a full 360-degree infinitely rotatable head design for operation in any position. Both tools offer audible "pop-off" to indicate properly completed crimps, and the BAT750 offers a green LED indicator for completed crimps, as well.

Greenlee also offers a diverse line of battery-operated crimpers, including its 6.2-ton Quad-Point Dieless Crimping tool, which features an angled pistol grip and a 360-degree rotating head, and its 12-ton Battery-Powered Crimping Tool, which also features a 360-degree rotatable head. Both the 6-ton and the 12-ton tools feature a ram that automatically retracts when the crimp cycle is complete and a two-speed pump to reduce cycle time.

The Penn Union hydraulic TDY-1 die-less compression tool allows workers to stock just a few sizes of standard Penn-Union color-coded lugs and splices to make all connections, covering the complete wire range from #4 Str. through 1,000 MCM-including compact wire. The tool and lug-and-splice are the ingredients for the company's ULTRA-CRIMP Range-Taking Compression System.

Some battery-operated crimpers use generic tool batteries; others require a brand-specific battery, which could be a problem should a battery die in the field.

Some battery crimpers require pulling a second trigger to return the dies when the crimp is completed. Others have automatic retraction. If such features are important for your workers, compare catalog specifications.

Hydraulic crimpers can be either hand-held compression or remote. With hand-held compression crimpers, the operator places the connector between the jaws and pumps the tool until the jaws crimp the connector to the proper pressure. Remote hydraulic crimpers feature a hydraulic pump physically separated from the head holding the jaws. The two are typically connected with a flexible hose. The pump can sit on the ground or hang from a shoulder strap; either position reduces the weight in the operator's hand and confers easy maneuverability.

Thomas & Betts Pumpac hydraulic pump, for example, rated to 10,000 psi, sports a 10-foot hose, and attaches to any T&B remote hydraulic head. T&B offers a variety of self-contained battery crimpers from 6 tons to 15 tons.

Defying easy categorization, the new Greenlee Textron CCX cut, crimp, and punch tool can crimp electrical connectors using several different die types, as well as cut a variety of materials, and punch holes, all with one head. Three types of CCX tools are available: battery-powered, hand-hydraulic, and remote hydraulic. The wide variety of snap-in adaptors makes refitting faster and easier than changing the whole head, notes the company, and takes up less space in a carrying case. The unit offers a rotating crimping head for aiding getting into tight places and automatic retraction of the ram after the crimp is completed.

By the way, connector manufacturers frequently run incentive programs that reward purchase of a large quantity of connectors (and sometimes a specific tool) with either other tools, free, or a credit toward another tool.

Companies mentioned in this article include:

FCI Burndy Electrical Products, www.fciconnect.com, (800) 346-4175

Greenlee Textron, www.greenlee.textron.com, (800) 435-0786

Huskie Tools, Inc., www.huskietools.com, (800) 860-6170

ILSCO, www.ilsco.com, (513) 533-6200

Panduit, www.panduit.com, (888) 506-5400

Penn-Union Corp., www.penn-union.com, (814) 734-1631

Thomas & Betts, www.TNB.com, (800) 888-0211

The FELDMANS are writers, and authors who provide Web content and write for magazines, trade associations, building product manufacturers, and other companies on a broad range of topics, They can be reached at wfeldman@worldnet.att.net or (914) 238-6272.