Electrical power is no longer a convenience but an absolute necessity. It’s how businesses keep the lights on, industries keep running, and households keep food rooms warm and food fresh.
This dependence, along with economic growth, technological advancement, and population increase, has driven a high demand for electricity. And as the size of the electrical market grows, so do the dangers of workplace exposure to electrical hazards.
In reality, almost every single facility has a need for electrical safety, since everyone from maintenance workers, janitorial staff, facilities staff, and equipment operators regularly interact with electrical equipment.
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In this article, I’ll go over the three pillars of a successful electrical safety program. If your workers face electrical hazards, ensuring their safety will require you to:
- Identify the need for electrical safety
- Verify electrical protective equipment before use
- Comply with equipment testing standards
Identifying the Need for Electrical Safety
Arc flash ( See Definition below ) and electrical shock injuries continue to pose a significant threat to workplace health and safety. Anywhere from five to ten arc explosions occur in electric equipment every day in the United States, and as many as ten U.S. workers are killed or injured according to CapSchell Inc., a Chicago-based research and consulting firm.
Definition – What does Arc Flash mean?
An arc flash is an explosive flash of light that jumps between two points on high powered electrical equipment. When an electrical current jumps between two points it is called an arc. Any equipment that poses the risk of an arc flash, needs to be labelled with a warning. An arc flash can have deadly consequences, thus everyone who works with that equipment should also be aware of the danger that it poses.
Moreover, the risks associated with shock and electrocution from inadvertent contact with energized parts have also long been recognized as a danger to workers, and they aren’t going away anytime soon (if ever). According to the Bureau of Labor Statistics (BLS), electrocution is the fifth leading cause of workplace fatalities in the United States, with more than 2,000 fatal and more than 24,000 non-fatal electrical injuries reported in the last 10 years. Since the BLS counts arc flashes as burns rather than in its electrical shock statistics, the true rate of electrical shocks is even higher. Furthermore, OSHA estimates that 80% of electrically-related accidents and fatalities involving “Qualified Workers” are caused by arc flash or Arc blast ( See definition below ).
Definition – What does Arc Blast mean?
An arc blast is the name given to the explosive burst of energy that occurs during an arc flash. An arc blast occurs as the result of a malfunction in the insulation between two energized phase conductors on high powered electrical equipment. Rather than flowing through a conductor, the current flows through the air, which releases thermal energy into the immediate environment.
OSHA rules and the NFPA 70E standard make the use of rubber insulting products mandatory when even the smallest probability of contact with 50 volts AC or higher exists. Regardless of the heavy fines, serious injuries, and deaths that occur from arc flash and electrical incidents, compliance continues to remain an issue. What’s even more shocking is that many workers are not using rubber insulating equipment because they simply don’t know they need it.
Electrical Safety PPE
While the best way to prevent arc or electrical incidents from happening is to de-energize equipment before beginning work, there are instances where turning off the power could create an even greater hazard. As such, employers and facility owners must establish safe practices to protect their workers against arc flash incidents, including guidelines for the proper use of personal protective equipment (PPE).
Rubber insulating products, such as the gloves, blankets, sleeves, line hoses, and hoods used by electrical workers today, are manufactured in accordance with industry consensus specifications under the auspices of the American Society for Testing and Materials (ASTM). These ASTM standard specifications are referenced in the OSHA regulations dealing with electrical safety, specifically 29CFR1910.137 covering Electrical Protective Devices, and 29CFR1910.269 covering Electric Power Generation, Transmission, and Distribution.
Bear in mind that rubber gloves are the only protective gear designed for constant contact with, and protection from, energized conductors and equipment. All of the other items are designed for protection from accidental, incidental, or brush contact.
Choosing the Right Rubber Insulating Gloves
Take care to choose the correct rubber insulating glove for the task at hand and level of electrical exposure. Rubber insulating gloves are typically manufactured in sizes 8 to 12 (often in half sizes), although options in sizes 7 and 13 are available from some manufactures. In addition, rubber insulating gloves are available in different cuff lengths of 11, 14, 16 and 18 inches depending on the glove class.
Rubber insulating gloves are available in six specific voltage classes (Class 00 to Class 4). Other rubber insulating products are available in different voltage classes as well.
|Proof Test VoltageAC / DC
|Max. Use VoltageAC / DC
|2,500 / 10,000
|500 / 750
|5,000 / 20,000
|1,000 / 1,500
|10,000 / 40,000
|7,500 / 11,250
|20,000 / 50,000
|17,000 / 25,500
|30,000 / 60,000
|26,500 / 39,750
There is a significant margin of safety between the proof test voltages and the maximum working voltage. Gloves\a and other rubber insulating products must be permanently marked to indicate the voltage class, and the gloves and sleeves must also have a color-coded label identifying the voltage class.
Verifying Product Integrity with Visual Inspections
OSHA and ASTM standards also require regular inspection of in-service electrical protective equipment in order to maintain compliance and ensure the products’ safety and integrity when exposed to a wide range of voltages.
Visually inspecting rubber gloves and sleeves identifies physical, chemical, or ozone damage. Inspecting under direct light is recommended because it enhances the ability to see surface imperfections on the rubber. Inflating the gloves with air or otherwise stretching the surface helps identify age and ozone damage as well as other physical damage such as snags, rope burns, deep cuts, and punctures.
Expand the gloves no more than 1.25 to 1.50 times their normal size. Listen for escaping air to detect holes. If a portable inflator is not available, use a rubber glove inspection tool or roll the glove cuff tightly to trap air inside. Then, apply pressure to areas of the glove to inspect for escaping air. Repeat the procedure again with the rubber gloves turned inside out.
All rubber insulating equipment should be thoroughly inspected prior to use. Common problems to look for include the following:
- CRACKING AND CUTTING– PROLONGED FOLDING OR COMPRESSING CAN CAUSE THIS TYPE OF RUBBER DAMAGE.
- UV CHECKING– STORING IN AREAS EXPOSED TO PROLONGED SUNLIGHT CAUSES UV CHECKING.
- CHEMICAL ATTACK– OILS AND PETROLEUM COMPOUNDS CAN CAUSE SWELLING OF THE RUBBER.
- AVOID FOLDING– THE STRAIN ON RUBBER AT A FOLDED POINT IS EQUAL TO STRETCHING THE RUBBER TO TWICE ITS LENGTH.
- SNAGS– WOOD, METAL SPLINTERS AND OTHER SHARP OBJECTS CAN SNAG OR TEAR RUBBER.
- PHYSICAL DAMAGE– ROPE BURNS, DEEP CUTS, AND PUNCTURE HAZARDS ARE CAUSE FOR REJECTION.
Perform Electrical Testing for Continued Compliance and Cost Savings
Various ASTM Manufacturing and Acceptance standards mandate the testing of the rubber insulating products by the manufacturer or supplier prior to the first delivery to the end user.
Users also have the option of performing or requiring an acceptance test upon receipt of the goods and prior to placing rubber insulating products into service. Once placed in service, there are periodic re-test intervals specified in the following ASTM standards:
- ASTM F496 Rubber Insulating Gloves– 6 months (under very limited conditions this can increase to 9 months)
- ASTM F496 Rubber Insulating Sleeves– 12 months
- ASTM F479 Rubber Insulating Blankets– 12 months
- ASTM F478 Line Hose & Covers– when field inspection or company policy warrant
Note that these in-service re-test intervals are the maximum permitted and must be performed in addition to daily field care and inspection. It is quite common for users, including power utilities and contractors, to specify shorter intervals. Do not, however, place rubber insulating products into service unless they have been electrically tested within the previous 12 months.
Rubber goods should be electrically tested at their rated test voltage using specialized equipment designed to gradually increase the voltage to the desired test level. The dielectric test is two-fold:
- Pass/failon the ability to withstand the rated test voltage
- For gloves, quantitativeon the ability to prevent electric current from passing through the rubber gloves above the maximum listed in the specifications
Products that pass the inspection and test procedures can then be returned to service.
Testing is a critical component to electrical safety – not only does it help maintain compliance, but it also increases savings. Rubber insulating products are costly, and these costs are often unnecessarily increased by purchasing replacements for products that could have remained in service with the proper testing and re-certification.
If you don’t have the equipment required to perform these electrical tests, there are independent testing facilities that can perform the acceptance and in-service testing on behalf of end users. ASTM standards recommend that the inspection and testing process include the following steps:
- CHECK IN
- REMOVING PREVIOUS TESTING MARKINGS
- WASHING WITH CLEANING AGENTS THAT WILL NOT DEGRADE THE INSULATING PROPERTIES
- VISUAL INSPECTION (INSIDE AND OUT)
- ELECTRICAL TEST
- FINAL INSPECTION
- PACKING IN APPROPRIATE CONTAINERS (TO PREVENT FOLDING, CREASING, OR SIMILAR STRESS ON THE RUBBER) FOR STORAGE OR SHIPMENT
When selecting a test lab for use, make sure it is NAIL (National Association of Independent Laboratories for Protective Equipment Testing) accredited. NAIL provides the only Laboratory Accreditation for electrical equipment test labs in North America.
Nearly all industrial workplaces have a need for electrical safety, and failure to comply can result in heavy fines, serious injuries, and even death.
OSHA and ASTM standards also require regular inspection and testing of in-service equipment in order to maintain compliance and ensure the products’ safety and integrity when exposed to a wide range of voltages.
Fortunately, there are practices that you can easily implement into your electrical safety program to help you prevent injuries, avoid citations and penalties, and curb superfluous spending. It starts with awareness of the need for electrical safety, and includes visual inspection as the first line of defense for your electrical safety products with periodical re-testing for continued confirmation of the equipment’s effectiveness.