Safety practices dictate that power lines and equipment must be de-energized before electricians can work on them. Only qualified people are permitted to work on live circuits under special circumstances, and they must use proper safety protection and equipment, which includes insulated tools.
Electricians often must work in close proximity to energized lines or components, and, in such situations, insulated tools are required to provide protection if a tool should come in contact with an energized source, according to Occupational Safety and Health Administration (OSHA) 1910.335(a)(2)(i).
The National Fire Protection Association (NFPA) 70E standard addresses safety when working around exposed, energized circuits, and complying with its provisions will result in compliance with OSHA regulations. These standards provide effective guidelines for safety. Local codes also may apply.
Many hand tools have cushioned grips that could be mistaken for insulation. Genuine insulated tools are identified with the international 1,000-volts (V) rating symbol, certifying they have been individually subjected to 10,000V. Insulated tools are available individually or packaged in kits.
Nathan Buckert, product manager, Ideal Industries, Sycamore, Ill., said several agencies participate in the design and performance criteria for insulated tools.
“In the U.S., the best-known and probably the most stringent enforcement criteria, is Underwriters Laboratories [UL], which requires each individual tool be tested to 10,000V to achieve a 1,000V rating; that’s a 10-to-1 safety factor,” he said. “Other agencies around the world, such as VDE, ANSI/ASME, ISO and ASTM, contribute to standards for design criteria, but may not require 100 percent individual testing.
“Insulation is a function of the type, thickness, design and maintenance of the plastic insulation encapsulating each tool. Quality ranges from dipped vinyl to high-pressure, injection-molded, dual-durometer, Santoprene thermoplastic resins,” Buckert said.
The material, by itself, isn’t enough to achieve a safe insulation. Safe design also is a factor in the insulation attributes of a 1,000V-rated tool.
“Most manufacturers of insulated hand tools have moved away from dipped vinyl to injection-molded insulation,” Buckert said. “Dipping a tool in liquid vinyl is something of an art; every tool drips the liquid off differently during the curing process. That inconsistency is not always visible, but it results in thick and thin areas throughout the hardened resin. Injection molding is the technical and repeatable solution. Each mold is specifically engineered for the required thickness of resin. As a result, every molded part meets specification.
“Another advancement is dual-durometer injection molding—literally molding one layer of insulating material over another to further enhance performance and to provide a visual warning if the outer layer gets damaged,” he said.
Buckert said most job sites where live work is being done will, at minimum, have the following insulated tools on hand: lineman’s pliers, diagonal cutters, needle-nose and tongue-and-groove pliers, wire strippers, and assorted slotted and Phillips screwdrivers.
“These tools always should be kept in a secure, protected location to preserve the integrity of the insulation from damage and to assure they are readily available when the need arises,” Buckert said. “Insulated tools should never be tossed into the tool box like an everyday hand tool. These are precision instruments.”
While strict standards for insulated tools have not changed much in recent years, technology advancements have resulted in insulated tools that are more compact and lightweight while still meeting the rigorous standards, according to David Klein, associate director of product management at Klein Tools, Lincolnshire, Ill.
“Insulation is achieved through a thick, high-dielectric layer that is bonded to the handle of the tool,” Klein said. “This layer serves as a barrier between the highly conductive steel handle and the user’s hand. We add an additional flame-retardant, impact-resistant orange layer to protect the integrity of the high-dielectric layer.”
Electricians typically use insulated side-cutting, diagonal and long-nose pliers, wire strippers and screwdrivers, Klein said.
“But, essentially any tool that could come into contact with live circuits should be insulated,” he said.
Care must be taken to prevent damage to insulated tools.
“Moisture, films or surface contaminants are conductive, so insulated tools should be kept clean and dry at all times,” Klein said. “Before each use, the hand tool should be inspected visually by the user. If there is any doubt concerning the safety of the tool it should either be scrapped or subject to examination by a competent person and retested if necessary. If retested, the Routine Dielectric Test is defined by ASTM F1505.”
Todd Shumate, president of Knipex Tools, Arlington Heights, Ill., also discussed the evolution of insulated tools.
“The primary change in insulated tools is that tools that were not available as insulated in the past, now are meeting the insulated tool requirements,” he said. “An example is our pliers wrench, which is easily adjusted for many size bolts and nuts and meets insulated requirements.
“Basic hand tools need to be treated with respect. Tools should not be thrown in a toolbox or drawer. In addition, insulated tools must be protected from abuse and extreme temperatures,” Shumate said.
Some tools can lose insulating properties from abuse and insulation nicks.
“Tools are tested before they leave the factory to 10,000V, and if the insulation stays unharmed, they will provide protection for a long time if used properly,” Shumate said. “Insulated tools need to be visually inspected before each use for cracks or gouges in the insulation. If any irregularity is found, the tool should be destroyed.”
Jeffrey S. Russo, senior vice president of Cementex Products, Burlington, N.J., said the insulation formula is unique to every company. The exact process is closely held.
“Pliers, screwdrivers and nut drivers lead the way in insulated tools used by electricians,” Russo said. “They are the basic and essential tools for almost any electrical worker.”
Insulated tools are required on just about every job site where electrical workers will be modifying, maintaining or overhauling switchgear, motor starters or battery banks.
“Not all insulated tools are created the same,” Russo said. “Insulated tools need to fit into areas of electrical cabinets, instrumentation and panels to work safely. There is a growing use of T-handles, ratchets, sockets and wrenches to break free lugs, nuts and bolts. These tools allow electrical workers to really access work within the known energized electrical components and be sure that they are working with tools designed with them in mind.
“T-handles are available in different lengths. Ratchets, torque wrenches, and sockets come in different drive sizes, lengths and functions. A ratchet and sockets are used break free nuts and bolts from terminal blocks or battery lugs. Hex bit and hex nut sockets are used with torque wrenches to tighten nuts or socket cap bolts on batteries or panel boards to the manufacturers torque specification.
“Wrench styles vary—there are fully insulated and bare head adjustable, box, open, ratcheting box, and new ratcheting open end tools. These items play a vital part in safe work practices,” Russo said.
Specialty tools have become hot items of late, including magnetic retrieval tools, flashlights and inspection mirrors. Compliance standards have made the use of these tools common. All tools referenced above must be 1,000V-rated, Russo said.
Cuts, nicks, cracks, punctures and other abrasions can lead to a tool losing the insulating value, Russo said.
“The principle of insulating tools is fairly simple,” said Jae Lee, product manager at Greenlee, Rockford, Ill. “The purpose of the insulation it to ensure there is no conductive path from the isolated contact point ‘business end’ of tool and the user. This can be accomplished by making the entire tool out of nonconductive material, such as ceramics, reinforced plastics or other composites, or, most commonly, by encapsulating the entire tool with the exception of the business end, with nonconductive material such as PVC-type material, polypropylene or other materials.”
Lee said there have been no major changes in the tool market, but the injection-molding process—instead of dipped or heat-shrink methods—allows the use of a larger variety of materials, including softer, more comfortable handles and better ergonomic features. It also enables the use of different color combinations.
For Greenlee, screwdrivers are the No. 1 insulated tool, followed by side-cutting pliers. Other popular insulated tools include wire cutters, long-nose pliers and nut-drivers, Lee said.
However, damage to the material, such as cuts, nicks or scrapes, can create pathways for electricity, negating the insulating properties.
“Insulated tools should be used and stored differently from conventional, noninsulated tools,” Lee said. “When not in use, they should be kept isolated from other tools, including other insulated tools, to prevent them from getting scraped or nicked. Insulated tools that meet [ASTM International or International Electrotechnical Commission] standards can withstand typical handling without diminishing the insulating properties. However, care should be taken to minimize unnecessary contact or impact to the insulated portions. In other words, don’t bang the tools, drop them or use them in a way they were not intended. And lastly, it’s good practice to keep the insulated portions clean as clean tools are far easier to inspect for any potential damage.
“The insulated properties can be confirmed with a dielectric test. However, this testing requires specialized equipment. The warranty or stated information for any insulated tool should be read and understood before use,” he said.