Incident Prevention Magazine

7 minutes reading time (1450 words)

June 2016 Q&A

Q: Is a transmission tower leg considered a lower level? And is there an exception for hitting a lower level when someone is ascending in the bucket truck to the work area? Our concern is that the shock cord and lanyard could be long enough that the person could hit the truck if they fell out of the bucket prior to it being above 15 feet.

A: The February 2015 settlement agreement between EEI and OSHA addresses both of your questions, which, by the way, were contentious for several years until this agreement. The settlement agreement includes Exhibit B (see www.osha.gov/dsg/power_generation/SubpartV-Fall-protection.html), which explains how the new fall protection rules will be enforced or cited by OSHA. Employers should review the entire document.

Section A of Exhibit B states that no citation will be issued because a fall arrest system could permit the employee to contact a lower level while the bucket is ascending from the cradle or to the cradle position, provided that the fall protection is compliant in all other respects, the bucket is parked with brakes set and outriggers extended, and there are no other ejection hazards present.

The document goes on to address falls from a bucket during which an employee may strike a structure. In this case, too, OSHA will not issue a citation if fall protection is compliant, the bucket is parked with brakes set and outriggers extended, and there are no other ejection hazards.

Instruction in Exhibit B also addresses climbers who climb past an arm on a tower, recognizing the impracticality of protecting a climber from striking a lower level if he or she should fall while climbing past. Readers will notice in the instruction that OSHA has reaffirmed an earlier opinion that tree limbs and conductors below the worker are not considered lower levels for the purposes of fall protection for climbers or in aerial lifts.

Q: We heard that OSHA cited a contractor for a Cranes in Construction violation for work involving a bucket truck equipped with a jib and material-handling winch. If the jib can lift, lower and move horizontally – which is the definition of a crane in OSHA 29 CFR 1926.1400(a) – can OSHA cite it under the crane rules? For that matter, would a lineworker in a bucket truck with a jib have to be a certified crane operator?

A: Bucket trucks are exempt from 1926 Subpart CC, “Cranes & Derricks in Construction” (see 1926.1400(c)(5) for the very clear exemption). OSHA may often cite a horizontal standard that is directly related to a vertical standard rule, but in our experience it is rare that the agency would cite a vertical standard rule to apply it against another vertical standard exposure or horizontal rule exposure. That may need some explanation. Horizontal standards are those rules that apply to all areas, such as PPE, ladders, scaffolds, trenching, confined space, electrical safety, material storage and so on. Vertical standards are those rules that only apply to a certain industry, like those found in 1910 Subpart R, “Special Industries,” including pulp, paper and paperboard mills; sawmills; telecommunications; and, of course, electric power generation, transmission and distribution. For instance, if a commercial building contractor was using a manlift and was not tied off, OSHA would not cite them under the aerial lift/bucket truck rules of 1910.269(g)(2)(iv)(C)(1). Vertical standards take into account special conditions that require hazard remediation specific to those conditions. Those special conditions are not appropriate to places of employment outside of those particular workplaces. However, those workplaces under vertical standards have to comply with those horizontal standards not specifically addressed in the particular rules of the vertical standards. For example, let’s say a substation crew decides to use scaffolds in their workplace; they won’t find scaffolds in 1910.269, but they are subject to the scaffold rules in the horizontal standard 1910.28, “Safety requirements for scaffolding.” This would also be the case with General Industry and Construction. Plant maintenance workers would not be held to a Construction standard even if the work they were doing was not addressed in the General Industry standard. If OSHA discovers a condition that cannot be appropriately cited under the General Industry standard, the agency would most likely cite the condition under the General Duty Clause.

Q: A question recently came up about truck grounding. Specifically, when grounded to the system neutral, should the truck be considered hot like we treat the neutral any time we are handling it? And should we install ground matting around the truck, wear removable rubber boots or use gloves when in proximity to the truck when the system neutral is used?

A: In the past, the industry norm was not to realize there was an intrinsic risk by connecting a truck to the system neutral. In fact, many utilities would not allow working a neutral in leather gloves because it was considered an energized conductor, but they would connect their trucks to the neutral and then bare-hand the truck. Your workers should be commended for recognizing this issue. The risk is to workers in contact with the truck, and the risk is greatest if a local fault – within four to five spans – occurs. Current on the neutral could be high enough to create a potential difference between the truck and the ground around it that could penetrate a worker’s leather gloves, boots and skin resistance, resulting in a shock. Some protection is provided by the neutral itself, and other pole grounds help to dissipate available current into the path of the truck. However, as most authorities will tell you, it may be that the path through the truck has the highest resistance, but it is the path itself that must be considered. There is no way to assure that random connections and resistive paths will not conduct a hazardous current into the truck if it is connected to the system neutral during a fault.

Now, let’s talk about the other side of the issue. Yes, it is unlikely – possible but unlikely – that a fault current from a distance away can put a dangerous current onto the truck. On the other hand, the current on the truck from a boom strike of an energized line could benefit from a system neutral grounding connection. Studies have shown that a well-grounded truck, in particular one grounded to a low-resistance system neutral, does conduct a significant amount of current into the neutral, affording protection to those higher-resistance paths on the earth or persons in contact with the truck. Still, there is no assurance when you cannot effectively predetermine the fault current and resistance of all the paths involved. Therefore we should have a system of protection like those required by OSHA 29 CFR 1910.269(p)(4)(iii)(C): bonding, equipotential mats and barricades.

The risk is a good reason to set criteria for grounding a truck. If a truck cannot become energized, there is no reason to ground it to the operating system creating the risk.

Q: We are having some difficulty understanding the difference between test voltages for hot-line tools. OSHA 29 CFR 1926.957(a)(1) states 100,000 volts per foot, but 1926.957(b)(3)(v)(A) states 75,000 volts per foot. Why is there a difference?

A: You are looking at the design factor for manufacturing of the hot-line tool at 100,000 volts per foot and the in-service testing voltage. In the U.S., OSHA has adopted both the ASTM design standard for fiberglass tools (100,000 volts) and part 5.6 – “Typical tests for insulating tools” – of the IEEE 516 standard (75,000 volts). By the way, 1926.957(b)(3)(v)(C) states that tools can be tested using “other tests that the employer can demonstrate are equivalent.” That is what you are doing if you use portable stick testers. Those portable testers test at about 1800 volts and then apply an algorithm to the measured leakage, indicating the condition of the stick. It seems to be a reliable method – at least, we are not aware of any issues – but most employers don’t know they are using a permitted other method that is equivalent to the 75,000-volt test.

Do you have a question regarding best practices, work procedures or other utility safety-related topics? If so, please send your inquiries directly to This email address is being protected from spambots. You need JavaScript enabled to view it.. Questions submitted are reviewed and answered by the iP editorial advisory board and other subject matter experts.

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