December 2023-January 2024 Q&A
Q: Our network group employees don’t work anything over 600 volts without working clearance. When working 480 volts, can they wear Class 2 sleeves with Class 0 gloves? We’ve looked through OSHA 29 CFR 1910.269 and are unable to find where it says they can’t.
A: We applaud you for attempting the research. OSHA’s perspective on the standards is to tell employers what they must accomplish (not how to accomplish it) or not to do it. Most of the time, your research begins with OSHA regulations. We look to them first because they are statutory and what we must answer to. When we understand OSHA’s expectation, we can then go to the related consensus standard for best practices.
The answer to your question is that it is not prohibited to don Class 2 sleeves with a lower class of gloves so long as those gloves are properly rated for the exposure. Of course, we wouldn’t want the use of sleeves to be an alternative to good cover-up where there are exposed bus connections. Networks are usually very high current and large copper cable delivering high-energy faults. They often require a system of cover, gloves and sleeves to keep network technicians protected.
Q: On a 34.5-kV subtransmission system, no neutral, is it permissible to rubber-glove with Class 4 gloves, or is it a requirement to use an alternate method (e.g., live-line tools or the barehand technique) if the line cannot be de-energized? Our training in Ontario, Canada, does not allow rubber-gloving this voltage level if it isn’t a grounded wye distribution system.
A: As of press time, we are still looking into the Canadian standards. The different jurisdictions may have different rules. In the U.S., the rubber-gloving you refer to is permitted under IEEE 516-2021, “IEEE Guide for Maintenance Methods on Energized Power Lines.” Following is the text of the rule, found at 7.4.2.1, “General guidelines.”
The following guidelines are recommended for the rubber gloving method:
a) References to voltages in the following subclauses are phase-to-phase on multiphase circuits. When exposure is limited to phase-to-ground voltage only, gloves rated for that voltage can be used with special precautions as listed in Part 4 of NESC [B1].
b) Rubber and synthetic insulating gloves and sleeves are available for use on voltages through 36kV.
Now, here are some practical considerations. Delta systems can be worked phase to ground. However, we need to consider that if we go to ground on any of the other phases in the delta system, the one in our hands could experience a voltage rise up to 36 kV. We expect that this phenomenon is a reason why some jurisdictions might prohibit the practice.
Q: What is the best practice when performing a bucket rescue if (1) the truck is equipped with a bucket elevator, (2) the boom and bucket are above the system neutral, and (3) the bucket is raised by the elevator an additional 2 feet closer to the energized phases? There are no lower controls for the bucket elevator, and getting the bucket and occupant down is much more difficult to do. Obviously, the one performing the rescue would get the lineworker down the best they could. Do you have any thoughts on the matter?
A: Our first concern is that you said the lower operation has no controls for the elevator. We have never seen that. ANSI A92.2, the standard for the design of aerial lifts, states in 4.3.3, “Lower Controls,” that lower controls shall be readily accessible in all boom positions and shall provide a means to override the boom-positioning upper controls provided the upper controls system is intact. We checked with some design and compliance contacts at Altec and Terex regarding that standard. Both suggested contacting the manufacturer of your equipment for verification and solutions that meet ANSI A92.2.
Q: When performing bucket rescue on a digger derrick or backyard machine equipped with a floating bucket with a manual brake, if the manual brake is engaged, how do you lower the boom of the equipment without dumping out the lineworker?
A: This is one of those questions that gets answered by trying the rescue in a safer space to see what the issues might be. We know the answer because several of Incident Prevention’s editorial advisory board members have already done this. But here is something that all rescues must address: If rescue from a boom-tip basket is for a worker who has suffered an electrical contact or burns, you cannot leave them suspended because they might fall out during lowering. If they are wearing a body harness and tied in, they won’t hit the ground. Even if they slide out into a fall protection harness, that would be better than allowing them to expire aloft without first aid for fear of spilling them out during rescue.
One consideration is the size of these backyard machines and digger derrick pin-on baskets. They are single-worker, so they don’t need a 6-foot lanyard. A shorter lanyard will still allow them to perform their work, and it will limit slide-out of the worker if the bucket is tilted during a rescue.
As far as bucket tilt, we did some graphical exercises and found that in most configurations, the angle of the bucket to the telescoping boom is such that lowering the boom would not completely invert the bucket as the boom comes down in reach of rescuers. We performed several boom angle/bucket angle simulations at an average boom working angle, and in every case, when the boom was at ground level, the bucket was not greater than parallel to the ground.
Q: We just had a near-miss where a jumper from the power leg in the panel to the ground was forgotten and left in place. This was caught prior to energization, so there was no fault. The crew was using the jumper to check continuity at the weatherhead to confirm tape marks prior to connection. We are working on corrective actions and wondering, could you share some best practices for verifying the power leg?
A: Well, it was caught, so that is a plus for the procedure, but it sounds like it was barely caught.
This is actually not new to us. It’s not unheard of for a crew to apply 208 volts to the wrong leg because the electrician tape-marked it wrong. We are familiar with a method that dispenses with jumpers entirely. Strip the high leg at the weatherhead and park it in the wedge of the neutral, effectively grounding it at the top. Then ring out the wire down at the meter base. That way, we have checked the two leads that matter: the neutral terminal and the high-leg terminal for both right leg and position in the meter base. The other two don’t matter as far as position, but we can ring those to be clear of grounds from the top.
Q: Is there an OSHA requirement for annual inspection and testing of full-body harnesses used in fall protection?
A: OSHA does not have an annual requirement for fall protection inspection. The agency considers the required daily inspection that the employee is trained to do and inspections by a competent person to be effective.
The agency does expect the employer to consider the manufacturer’s guidelines in inspection protocols, and a few manufacturers do have lifetime limits on the use of their body belts. Just read the labels to see if any lifetime use limits apply.
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