By K.D. Aiardo, Hi-Line Utility Supply
Lightning, human error, static electricity, induced voltage, backfeed… all reasons that the line you are working on could become energized. Keeping electricity grounded when work is being performed is critical to avoid electricity seeking your body as the grounding path. Staying safely grounded includes working with the correct equipment, daily inspections, proper cleaning, maintenance and recertification, and proper storage.
Before Beginning – Review Safe Work Practices
Completing a job safely should always begin with the knowledge and understanding of your company’s Safe Work Practices including a hazard assessment prior to work (see OSHA 29 CFR 1910.269(a)(3) & .269(c)). This will guide you through the completion of a job in a safe and efficient manner from beginning to end, and will include proper grounding practices.
Protective grounding should have an electrical impedance low enough to cause the immediate operation of protective devices in case of accidental operation of the lines or equipment (OSHA 29CFR 1910.269(n)(4)). Grounding equipment must be capable of conducting the resulting fault current that could flow at the point of grounding for the time necessary to clear the fault. Utilize a professional testing facility when custom building ground sets, such as Hi-Line Utility Supply, which will be able to build ground sets to your specifications, and to meet your needs on the jobsite.
Installation and removal of protective grounding should always be done with live-line tools, with the Ground-End connection being installed first (and removed last when removing the grounds) (OSHA 29CFR 1910.269(n)(6)). Live-line tools should be properly inspected before use for any damage that could inhibit their protective properties, and equipment that has suspected damage should be removed from use in the field (American Society for Testing and Materials/ASTM 711-02, 8.1) and sent to a professional testing facility. According to John “Grizzy” Grzywacz, Professor Emeritus of the OSHA National Training Institute, “Most utility accidents and fatalities with respect to line contact are a result of lack of either appropriate PPE, insulated line cover up or lack of appropriate grounding.”
The Correct Equipment for the Job
When building sets, you can choose from a variety of grounding components. Since grounding components (cables, ferrules, and clamps) are furnished to meet the needs of various applications, each must meet the maximum current that could flow through the completed set at any time. As a general rule, your equipment is only as strong as the weakest component. For example, if one component is a grade 2 and the rest of the set is equipped to meet the current flow of a grade 4, your grounding equipment is rated at a grade 2.
In addition to ensuring all components meet the fault current requirements for the job at hand, consideration should also be given to the clamp style and cable length. Under fault conditions, grounding cables can whip violently. For this reason, clamps should be selected based on what they will be clamped onto to avoid fly off. Stocking grounding sets of various cable lengths is advised as a cabling too long will create an added hazard (since ground clusters installed with excessive cable length can whip violently under fault conditions) and could cause further injury, additional damage, or worse.
Cable can also be purchased with colored jackets or clear. Colored jackets, such as yellow, can offer better visibility of the ground set and a clear jacket provide better visibility to the copper stranding within, making damage inspection easier. Ground cables are stated in American Wires Gage numbers (AWG), and are also classified by type. Specifications for temporary grounding equipment can be found in ASTM F855-1990.
Regular Cleaning and Storage
Regular cleaning of ground sets can prolong the life and safety of the set. Several factors can contribute to the demise and reduce the effectiveness of a set. For example, dirt and water can actually conduct electricity and the everyday petroleum-based products that grounds come in contact with can damage the integrity of the ground set and can reduce protective properties. Wire brushing of the ground clamps to remove corrosion and dirt, as well as cleaning of the grounding cable with a rubber goods cleaner, should be done immediately before and after each use. Don’t forget to wire brush the cable that the clamps will be attached to- proper cleaning will also allow for a better inspection of the equipment, and may yield damage that would have previously gone unnoticed. When sending in grounds for recertification or repair, a professional facility such as Hi-Line Utility Supply will take the time to remove all corrosion and dirt from the ground set, and the set will look like brand new and will provide peak performance. When storing ground sets, keep them in a protective ground set bag. As with all safety equipment, care should also be taken to ensure sets are stored in a temperature-controlled environment, out of direct sunlight and high humidity.
Inspection of clamps, cables, support studs, shrink tubing, and ferrules to ensure there is no structural damage should occur before each use. Clamps should be free of loose parts, sharp edges, splits, cracks, and should be able to be operated smoothly by hand (see ASTM F855-09, 10, 23, 36). Carefully inspect the area where the cable meets the ferrule for any breakage. Then begin inspecting the cable jacket for any corrosion (indicated by swollen or soft spots), flattened or smashed sections, or any cuts or breakage in the cable jacket. Any damaged ground set should be taken out of use and sent in for repair and recertification. While damage can sometimes be easily identified, regular wear and tear, extreme voltage, and moisture can all cause unseen damage. For this reason, an industry best practice is to establish planned repair and recertification intervals based on the type and frequency of work.
Maintenance and Recertification
Broken and damaged grounds should be sent in for repair and recertification. It is highly recommended that ground sets without seemingly obvious structural damage also be sent in for regular recertification. Certified test labs, like Hi-Line, completely disassemble and clean each component, including ferrules, clamps, and cable, and each are tested separately per ASTM standards. Any necessary repairs or replacement parts are made as the device is being reassembled, then the complete ground set is tested. Once the ground set passes testing, it is then labeled with test dates and due dates for recertification, which will keep crews in the loop about upcoming test interval expiration dates. The complexity of the recertification and repair process requires highly skilled and experienced personnel, and the industry trend is going towards having an experienced testing laboratory, such as Hi-Line, to complete these processes. Hi-Line Utility Supply tests and refurbishes over 22,000 grounds and jumpers per year, and also provides all required testing documentation including the additional certifications needed by most wind farms.
Proper grounding will not only keep you compliant, but will also ensure that you remain safe while working on the line. Remember, a line that is de-energized can easily become energized in the blink of an eye, so stay safe and safely grounded at all times, and remember, “If it’s not grounded, it’s not dead!”
Are your Grounds and Jumpers properly cared for, maintained and certified?
Hi-Line Utility Supply, a division of WESCO Distribution, Inc, is a provider of tools, equipment, and services for the Electrical Industry since 1960. Hi-Line’s two full service testing labs in Illinois and Massachusetts, refurbish over 22,000 grounds and jumpers per year, and test over 250,000 rubber gloves, sleeves, blankets, line hose, hoods and boots each year. Hi-Line also offers tool repair and fiberglass restoration. For additional information on Hi-Line’s Custom Grounds/Jumpers and Refinishing Services, please contact Hi-Line’s Customer Service Team at (800) 323-6606 or via email at email@example.com. www.hilineco.com