Published: March 2005
“Professional electricians pride themselves on quality, speed and accuracy of the connections they make,” said Bruce Hartranft, business unit manager, Ideal Industries. “A typical residential wireman will make upwards of 200 wire connections per day while wiring a new home. An average four-bedroom house contains 300-plus twist-on wire connections.”
Of course, the number of connections for commercial and industrial projects is many times greater.
Every apprentice learns early in training that making proper connections the first time is of utmost importance.
In extreme cases, a poorly made connection may result in the connector coming completely loose from the cable. Bad connections can cause overheating that may damage the conductor, the connector or the device or equipment being powered. Risks include shorts, arc faults, fire, personal injury, inoperable equipment and reduced life of equipment.
Connectors fall into two general categories: mechanical and compression.
The tools needed depend on the type of connector, how it is to be used, and size and type of cable.
Basic tools for making connections are cable cutters, strippers to remove the insulating jacket, hand tools for making mechanical connections and crimping tools to install compression connectors. By the application of force, a crimping tool makes a permanent connection by either compressing (crimping) a connector around a stripped wire or cable, or by pushing wire or cable into a connector designed to pierce or displace the insulation and attach to the conductor.
“Tools may have a specific range,” pointed out Bob Poirier, tooling product manager, FCI-Burndy Products. “An example would be a manual or ratchet tool to install connectors on cable only up to 4/0 copper or aluminum. A six-ton battery actuated tool can be used on connectors up to 600 Kcmil. If the application calls for something larger, a 12-ton battery-actuated tool can be used, and there are also self-contained hydraulic tools available.”
Jim Eisele, product manager, Greenlee Textron, said smaller cables (250 Kcmil and under) can easily be cut and crimped with manual cable cutters and crimping tools.
“But,” he said, “when a high volume of connections need to be made, the job is much easier and faster with manual-hydraulic or battery-powered tools. It can take a lot of strength to cut the cable and crimp connectors for large cables with manual tools. Therefore, ratcheting cable cutters and manual-hydraulic and battery-powered cable cutters and crimping tools are often used. It should be noted that use of manual tools to cut and crimp large cable and connectors over many years may contribute to repetitive-motion injuries to chest and shoulders. Many companies are switching to battery-powered tools to help prevent these injuries.
“Battery-powered tools have made the cutting and crimping processes easier, faster, and very consistent,” he added. “Some manual-hydraulic and battery-powered tools automatically open to notify that the crimp is complete.”
The most prominent connectors are lugs with a hole on the end, allowing the connector to be attached to a piece of equipment using a bolt, Eisele said.
“They can be compression connectors that require a crimping tool to attach them to the cable, or they can be mechanical where tightening a bolt attaches them to the cable,” he continued. “Also common are splices that are used to connect two cables together. They are also available in compression versions and mechanical versions. These connectors are color-coded for cable size.”
Ideal Industries and other manufacturers, Hartranft noted, have developed tools specifically for cutting, stripping and terminating wire and cable.
“A new screwdriver design provides three key functions electricians need on every job,” said Hartranft. “The universal wire connector wrench quickly tightens twist-on wire connectors, the large-blade screwdriver tips can be used to install the fixture, and the small-blade tips can then be used to install outlet covers. One tool with three functions speeds the work and improves the quality of the installation.”
Precise wire cutting and stripping is imperative to making quality wire connections, Hartranft said. Stripping tools ensure accurate, no-nicks preparation of wire for terminations. Many strippers come with crimp dies for use on crimp connections, bolt cutters for preparing fixtures for attachment, and wire-looping features to prepare wire for screw-mount terminations.
Hand crimp tools are used daily by commercial and residential contractors, whereas hydraulic powered crimps are used by utility and heavy industrial electricians. Crimping tools are used with bare and insulated crimp connectors to obtain a quality, UL-approved, wire connection. Hand crimp tools range in size from small 22 AWG to 2 AWG wires and crimps. Power crimps go up to 750 MCM for use with utility power cables. Patented four-way tools have a design that ensures even crimp compression and reliable connections.
While it isn't a tool, antioxidant and anti-seizing compound improves efficiency and service life of aluminum-to-aluminum and aluminum-to-copper connections, Hartranft said. Suspended zinc particles penetrate and cut aluminum oxide. Compounds are for use in all types of pressure-type wire connectors including screw-on, tap, service entrance and split-bolt.
Two types of crimping tools
Robert A. Klaviter, Panduit business development manager, said die-type tools require coordinating color-coding of connectors to dies and installing them into the tool to make a proper termination. Dieless-type tools don't require dies; they rely on the indenter incorporated within the tool to make a proper termination.
According to Klaviter: “The compression-force rating of the tool limits the size of the connector that it can terminate. Small mechanical hand tools are lightweight and easy to use; however, their lightweight frame and limitations of their mechanical linkage restrict their capability to a limited-size range of connectors at the low end of the wire-size spectrum. Hydraulic systems with robust crimp heads provide a higher level of crimping force (from six to 15 tons) and are capable of crimping a wide range of connector sizes. Originally hydraulic crimping tools required manual-pumping force to pressurize the hydraulic system of the tool or required an electrically operated hydraulic pump and hose system to pressurize the crimp tool. The latest-generation of crimping tools is battery operated using rechargeable batteries to power the hydraulic systems. These new tools are completely self-contained, lightweight, compact and provide a fast crimp cycle time.”
Ergonomics has become a key factor in tool design, and today's connection tools are lighter in weight, easier to use and more durable than older models. Improved shapes make them more efficient and reduce physical stress during use. Wire strippers, for example, are shaped to take strain off the weaker areas of the wrist, lessening the chance of repetitive-motion injuries and allowing users to do more work in less time.
“The advent of battery-powered crimping tools provides tools with compressive forces from six to 15 tons in a self-contained unit,” said Klaviter. “Tools are typically handheld, lightweight, with push-button operation and powered by rechargeable batteries to provide continuous operation. Their small size allows operation in confined spaces. The battery-powered push button hydraulic systems eliminate manual labor and fatigue making their operation safer and more ergonomic than manually powered tools.”
The continuing evolution of tool design is influenced by new types of connectors.
According to Ideal's Hartranft, push-in wire connectors eliminate the need to twist on wire connectors and are perfect for residential, lighting retrofit, OEM lighting manufacturing, prefabricated wiring systems, and other OEM and branch-wiring circuits.
Klaviter said that new copper HTAP connectors incorporate a slotted design, which allows the use of a cable tie to secure wires to the connector before termination. The use of cable ties in this manner both reduces the amount of labor to prepare the connector for crimping and ensures the conductor remains in the wire port. During termination, the slotted design facilitates the formation of a homogeneous mass between the conductor and the connector, resulting in premium electrical performance.
Crimp dies used with the connector emboss large easy-to-read die index numbers that can be read regardless of the orientation of the connector after crimping; this enables post-crimp inspections. EC
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at 405.748.5256 or firstname.lastname@example.org.