October-November 2025 Q&A

Q: We hear lots of opinions about whether a lineworker can lift a hot-line clamp that has a load on it. There is a rule that says disconnects must be rated for the load they are to break. We’ve been doing it forever. Are we breaking an OSHA rule or not?

A: We have answered this question before, but it won’t hurt to revisit it and use this opportunity to explain how OSHA analyzes a scenario to determine if it’s a regulatory violation. Most objections to operating a hot-line clamp (HLC) under load are based on 29 CFR 1910.269(l)(12)(i), which states that the “employer shall ensure that devices used by employees to open circuits under load conditions are designed to interrupt the current involved.” Some utilities prohibit operating HLCs energized, and there’s nothing wrong with that. Incident Prevention’s objective is to enlighten and educate the industry, not to judge an employer’s operational rules.

On its face, the rule seems to prohibit the use of an HLC to break load. Anyone could argue, then, that any operation of an HLC must be dead-break since HLC manufacturers offer no load-break value. However, when analyzing the intent of the rule, there are a couple points to consider.

First, if a non-rated HLC can’t be lifted under load, what about a dropout switch? We operate those thousands of times a day without employee injury, although sometimes an ill-advised operation does smoke a pole top. There is nothing in the rules that prohibits an employer or employee from making an informed and experience-based decision. The employer can – and should – establish criteria or protocols for operating HLCs or dropouts under certain load conditions. Primarily, the employer’s determination would be based on risk to the equipment and the employee. OSHA’s primary consideration is risk to the employee. As with the working-alone rule, there would be no violation if the device were operated by a hot stick from a position that prevented employee injury.

Second, what would be the solution to this scenario? If it required jumping out a jumper and installing a load-break switch, would that operation create additional risk exposure for the crew? Further, would adding the switch truly enhance the safety of the operation? In the very worst case, this scenario (i.e., operating the HLC under load) could be ruled a de minimis violation. Such a violation indicates that although OSHA recognizes a direct rule was broken, there was no other way – or no safer way – to execute the task, nor was there any risk to the employee. Regarding equipment damage, we try to operate without burning anything down, but OSHA’s bottom line is employee safety. The agency is not concerned with pole-top fires or system relays so long as no one is at risk of being injured.

Q: Setting up bucket trucks on slopes is a common issue, so why doesn’t OSHA provide any guidance about it?

A: Part of the answer is that OSHA doesn’t tell employers how to perform tasks. Though the most recent rulemaking has occasionally leaned toward dictating procedures, historically the rules have been written to tell the employer what must be accomplished in certain scenarios – not how to accomplish it. OSHA resorts to appendices when they want to tell us how to do something. The appendices contain procedural language, such as this statement found in Appendix C to 1910.269: “The Occupational Safety and Health Administration will consider employers that comply with the criteria in this appendix as meeting § 1910.269(n)(3).” There is no specific OSHA guidance about truck setups on slopes. In the absence of a specific rule, under the General Duty Clause, the employer is expected to ensure safe equipment operation in the workplace under all conceivable conditions. The manufacturer is the employer’s most obvious resource for information about safe operation.

Regarding equipment and tool use, OSHA frequently references manufacturer design specifications throughout the rules. In any equipment incident, the manufacturer is the first place OSHA compliance officers will go. Employers may have competent engineers making determinations, but an employer’s policy for setting up a piece of equipment should be strictly governed by the manufacturer’s operator manual. It will list the maximum safe slope angle and the recommended orientation of the vehicle to the slope. And while it isn’t as common in utilities, many construction crews have a dozer on-site; provided there are no environmental considerations, an operator can cut a flat on which to set-lift equipment.

Q: We were recently discussing whether to ground equipment operating in a substation. If the station rock bed is good, how much electrical isolation does it provide? Is that reliable as protection from step and touch?

A: Understanding the purpose of the rock bed and how grids are designed will give you a good basis for developing your safe work plans. The resistivity of crushed rock used in substations is about 3000Ω-m depending on material, sieve size and condition. That crushed rock is part of a system of protection devised to conduct faults to earth, limit voltage rise across the station, and control potential gradients across the surface of the earth inside the station. In one sense, the ground grid acts like a large equipotential mat except that unlike the mat – which is a floating plane parallel connected to a conductive circuit – the substation grid is grounded at numerous points and serves as a series-conducting electrode, passing fault current into the earth. The grid itself is designed to meet grounding and fault-conducting duty and, in conjunction with earth’s resistance, an equipotential plane.

Still, at the speed of light, there are instantaneous differences across the mat that can create voltage rises between any two points. The three functions mentioned above are mostly accomplished by the grounds and grid installed and the layer of compressed earth over the grid. The rock layer’s resistivity is another buffer intended to keep the voltage gradient at a tolerable level in the event of a fault in the station. The risk of step potential depends on a worker’s proximity to the current source and the magnitude of the fault. A well-designed system has very low resistance to earth. The isolating rock layer provides resistance between the grid and walking surface, further reducing voltage rise between the worker’s feet. The design calculations are complex and based on relatively reliable assumptions, as evidenced by the thousands of hours personnel have spent in stations without incidents related to step potential.

However, grids do sustain damage, and rock decomposes and becomes contaminated. We cannot recommend using the rock layer as a principal means of protection since it can’t be tested to ensure it is providing isolation. The grid can protect against step potentials, but if your equipment contacts an energized bus in the station, touch potentials between your truck and the grid still exist. We advise treating the equipment operating in the station just as you would in the field. Use barricades to denote clearances, and keep your equipment isolated from touch while booms are in the air.

Q: We are a contractor that performs substation and transmission construction in the eastern U.S. Several of our clients have asked about our lockout/tagout program. We are exempt from LOTO in terms of overhead lines, but what about in substations?

A: We are not exempt from the requirements of hazardous energy control. “Lockout/tagout” is part of the issue; the term is somewhat foreign to the transmission and distribution side of the utility industry. OSHA’s 1910.269 standard has energy control requirements in parts (d) and (m) that are especially designed for the peculiarities of the industry, but that doesn’t mean we are exempt from 1910.147, “The control of hazardous energy (lockout/tagout),” common to all other industries. For every workplace, there is a basic requirement that the employer must perform analysis and create compliant, workplace-specific procedures to implement hazardous energy control. Transmission and distribution equipment in the field does not have lockable switches except where a switch’s mechanical or motor operators are at ground level.

In generation and substations, many devices are equipped and must meet the locking or tagging provisions of 1910.269(d), “Hazardous energy control (lockout/tagout) procedures.” Notice the term “lockout/tagout” in parentheses.

Lastly, the note to 1910.269(d)(1) states the following: “Installations in electric power generation facilities that are not an integral part of, or inextricably commingled with, power generation processes or equipment are covered under §1910.147 and Subpart S of this part.” OSHA 1910.147 is the old General Industry lockout/tagout standard, and Subpart S is the General Industry electrical standard. Appendix A to 1910.147 includes the minimal requirements for a typical program.

On a related note, by most interpretations, those parts of the plant not inextricably linked to the generation of electricity are shops, warehouses, meeting/training/office spaces and maintenance areas.

To recap, all employers must identify hazardous sources of energy and then provide means to isolate and control them. Once the hazards and control methods are established, the employer communicates the procedures and, as necessary, provides training on how to install the control devices. If an energy source can be locked out, it must have a lock installed unless the employer can ensure that tagging alone is an effective alternative. In the field, controls must be implemented so that system operations and employee safeguards are as reliable as installing locks.

Do you have a question regarding best practices, work procedures or other utility safety-related topics? If so, please send your inquiries directly to kwade@utilitybusinessmedia.com. Questions submitted are reviewed and answered by the iP editorial advisory board and other subject matter experts.