OSHA’s 29 CFR 1910.269(a)(2)(ii) standard states that qualified employees shall be trained and competent in:
• The skills and techniques necessary to distinguish exposed live parts from other parts of electric equipment;
• The skills and techniques necessary to determine the nominal voltage of exposed live parts;
• The minimum approach distances specified in this section corresponding to the voltages to which the qualified employee will be exposed; and
• The proper use of the special precautionary techniques, personal protective equipment, insulating and shielding materials, and insulated tools for working on or near exposed energized parts of electric equipment.
These requirements are the basis for the entire spectrum of safety in this trade. Each one of these points builds on the previous one, and each rule is then built upon a complete understanding of the four points combined. Identifying energized surfaces is necessary to our work, but we can quickly get into trouble if we don’t understand what nominal voltage means. If one refers his work only to a phase-to-ground voltage like 7,200 or 14,400 volts, the PPE he uses can be totally wrong if he is working on a three-phase system. This may seem elementary to a utility lineworker, but when a contract crew is brought onto the property, it can mean the difference between working safe and being electrocuted.
The Importance of “What Ifs”
Knowing the nominal voltage affects the minimum approach distance (MAD) as well. Take the difference between a voltage of 14.4kV and 25kV – the difference in the MAD is 5 inches. This is a significant distance, especially when it comes to stringing new conductor and the placement of the travelers. It is important to ask yourself the “what ifs.” What if the traveler moves on the arm because it wasn’t tightened enough? What if the wind is blowing and the conductors are swaying at different levels, which would be the case if they were different sizes? We would want all the clearance we could get and 5 inches could make a difference. Remember, most accidents don’t occur just because of one error, but because of several.
Years ago, shortly after entering the trade, a foreman for our contracting utility was killed. They were running new conductor. On a rather tight corner, they had put up an angle block on the crossarm. They had adequate clearance and as they were starting up the pull, the foreman reached up to test the tension on the running ground. At that time the angle block slid, contact was made with the energized conductor and he was killed. It was a freak accident, but a situation where a little more clearance could have made a difference. Also, the fact that he wasn’t wearing rubber gloves was definitely a contributing factor.
The selection of PPE is always based on the nominal voltage and not on the phase-to-ground voltage, unless the line spacing is such that a person working on the line is always in a phase-to-ground situation.
Not as Simple as They Seem
These four points identifying the requirements of a qualified employee may seem simple for one procedure. However, when you consider the many operations that a journeyman lineworker must learn, it is easy to understand why an apprentice must work 6,000 to 8,000 hours to become a journeyman. Once the apprentice understands the importance of these four points, he is well on his way to having a safe career.
After being responsible for apprentice lineworkers and apprentice wireworkers for the last 15 years, I want to emphasize the importance of these four points, especially to people in the safety field. In teaching 29 CFR 1910.269 classes since the inception of the regulation, I have found that when you say “nominal voltage,” most people don’t know what you’re talking about. Perhaps OSHA could have phrased it differently so it would be easier to understand, but they didn’t. For the safety of new people entering the field, we have to teach them what nominal voltage means and its relationship to the other three qualification requirements.
About the Author: Chuck Woodings has worked in the electric utility trade since 1964, and has been a safety instructor and safety and training director for the last 20 years. As a job training and safety instructor, he helped develop a 29 CFR 1910.269 training program used to train employees of more than 100 utilities on the West Coast. Woodings worked all around the country throughout his career, finally settling in Boise, Idaho, in 1997. He became a Certified Utility Safety Professional in May 2011.