Published: October 2005
Electricians must often work near energized circuits, and in those situations, there are insulated tools and protective equipment to reduce the risk of serious injury.
Obviously, it is best to deactivate a circuit before working on or in proximity to it, but when that cannot be done, it makes sense to take every safety precaution available. If common sense is not reason enough to work safely, always remember that Occupational Safety and Health Administration (OSHA) requires it.
Insulated gloves, face shields and protective clothing all are essential for protection against shock, arc flash and arc blast, but we are going to focus on insulated tools.
With today’s emphasis on user-friendly tool grips, some tools can appear to be insulated when they are not. These will not provide you with real protection.
Tests and standards
“The modern definition of an insulated tool in the United States is a 1,000-volt rated tool that has been individually subjected to 10,000 volts, plus a variety of other tests as stipulated in the ASTM F1505 standard,” said Jeff Konkle, Klein Tools product manager.
Such tools are identified with the international 1,000-volt rating symbol.
Insulated tools also comply with the International Electrotechnical Commission (IEC) 60900 standard. The National Fire Protection Association (NFPA) 70e standard addresses safety when working around exposed, energized circuits.
Complying with its provisions will result in compliance with OSHA regulations. NFPA and other standards provide effective guidelines for safety, but these are not enforceable. OSHA can enforce its standards, including those pertaining to shock and arc hazards that require the use of insulated tools.
The first attempts to insulate tools were likely made by electricians who wrapped electrical tape around the handles of pliers and screwdrivers.
“Manufacturers began offering plastic dipped handles on pliers in the early 1900s, but these were primarily for comfort, not insulation,” said Konkle. “Before standards were developed, manufacturers were ‘insulating’ tools with various thicknesses and di-electric strengths of plastic, but there was no baseline for what was or wasn’t truly insulated. As di-electric properties of various plastics became better known, plastic dipping improved and more and more insulated tools became available.”
Today the hand tools most commonly used by electricians are available in true insulated versions.
“A full range of pliers, from side cutters and long nose to diagonal, crimping pliers and screwdrivers are available as insulated tools,” said Jon Howell, Ideal Industries product manager for hand tools. “In addition, nut drivers and now sockets, wrenches and specialty tools—such as adjustable wrenches, cable cutters and hacksaws—are available in insulated form. And more and more tools are being made that conform to the ASTM standard for insulated tools. Examples include screw-holding screwdrivers and composite tools.”
Technology has changed the way tool manufacturers achieve insulation, bringing tools with injection-molded handles and composite tools to the North American marketplace.
Ben Bird, president of Certified Insulated Products (CIP), said European manufacturers offered tools with composite grips before they were available in the United States.
“They have been doing it longer in Europe because the volume of demand was high enough to justify the cost of the developing the tools,” Bird said. “While some companies here still coat over handles, American companies now make molded grips, which are very good insulated tools. And the introduction of composite tools is one of the more interesting developments resulting from OSHA’s requirement for insulated tools with a 1,000-volt rating.”
Injection molded tools
Howell said injection molding allows handles to be shaped to best fit the electrician’s hand, rather than having to match the shape of the tool like dipped tools do.
“In addition to the ergonomics this provides, this also allows manufacturers to use both softer plastic insulating materials that are more comfortable in the hand and more durable harder plastic,” Howell said. “At first, this might seem to be contradictory, but consider a molded plier’s handle: the underlying layer can be molded of extra tough, hard plastic that resists damage, cuts, wear, etc., while the overlying layer—usually a different color—can be molded of a soft, comfortable, ergonomic material that feels more comfortable in the hand. And plastic technology has advanced to the point that materials like Santoprene can be used [with] their di-electric properties and which are also resistant to oils and chemicals and don’t get slippery when hands are wet or sweaty.”
Klein’s Konkle said his company’s insulated pliers use injection-molded handles that are made of urethane, the same type of plastic used in inline skate wheels.
“It wears exceptionally well and resists damage better than other plastics,” Konkle said. “Injection-molded grips also provide more consistent dimensional control than dipping, providing reliable insulation thicknesses and consistent contours and comfort.”
The advantage of composite tools is that the whole tool is made of nonconductive plastic, so there is no metal under-structure that can conduct electricity, and no outer insulating layer that might crack and expose the metal.
“The disadvantage is that composite plastics, no matter how good, still aren’t as strong as metal and won’t withstand the stresses that a metal tool can,” said Konkle.
According to Howell, composite tools are usually made entirely of composite glass-filled plastic.
“In screwdrivers, the plastic material makes up the shaft so the only metal is at the very tip. These tools are generally more expensive than standard tools and are not always as strong, but they can be a good alternative because they are not susceptible to failure from damage to the tool,” said Howell. “For example, if a composite shaft screwdriver gets cut or nicked, it is still safe to use because the shaft is plastic all the way through.”
Bird said composite tools take advantage of the inherent nonconductive, lightweight and high-strength properties of composite materials to transmit torque and leverage to the working end in the tool. Strength of composite plastics should not be a concern.
“A strong person can apply torque at six-foot pounds,” Bird said. “Metal yields at 10-foot pounds, and composite fails at 20-foot pounds. Composites allow the total elimination of insulating coatings that become nicked, cut or torn during normal use. If kept clean and dry, there is no conductive path back to the user’s hand.”
He added that composite tools are durable, lighter in weight and slimmer than other types of insulated tools, allowing access to extremely tight areas.
Insulating properties are not the only important feature of insulated tools.
For example, Konkle said, today’s standards specify integral thumb guards on insulated pliers that provide additional protection against touching the exposed part of the tool or the circuit.
“Some insulated tool manufacturers are seeking to incorporate added comfort and slip resistance into their tools and have taken steps to make more durable insulation that withstands impact tests even in extreme temperature conditions,” said Konkle.
According to Bird, composite screwdrivers and nut drivers are the only American-made products of their kind that pass ASTM extreme cold-weather tests.
Can tools lose insulating protection?
Yes, said Howell: “A tool will lose its insulating properties if the insulation is compromised, exposing the underlying conductive material. If the plastic is cut, cracked, scuffed, etc., then the insulating property of that plastic has been lost. For composite tools, cracks or damage may cause a composite tool to break, which can lead to other safety concerns.”
Some plastics break down over time—PVC-dipped insulation eventually deteriorates and cracks, so it is important to inspect tools before each use.
While there are tests that can confirm insulating qualities of individual tools, some tests performed repeatedly can break down the integrity of the insulation, hastening the need to replace the tool.
Two-layer, two-color insulation is designed to help users identify cuts in the outer layer by exposing the inner layer if the outer layer is cut or damaged. How effective this is depends on the contrast between the two colors and how carefully visual inspections are made.
Properly caring for insulated tools protects insulating materials
“Insulated tools should be stored to minimize damage to the insulation. Keep them away from sources of heat and sharp objects that could puncture or tear the insulation,” said Konkle. “Some manufacturers offer insulated tool sets in cases that have been specially designed to minimize damage. Insulated tools should be kept clean, dry and free of contaminants. Contaminants can be removed by washing with mild detergent and water, but be sure to thoroughly dry the tools before use. Harsh detergents should be avoided, especially on PVC-dipped tools because they can prematurely age the plastic.” EC
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at 405.748.5256 or firstname.lastname@example.org.