Incident Prevention Magazine

10 minutes reading time (2073 words)

April-May 2019 Q&A

Q: OSHA’s digger derrick exception – found at 29 CFR 1926.1400(c)(4) – includes digger derricks when they are used for augering holes for poles carrying electric or telecommunication lines, for placing and removing the poles, and for handling associated materials for installation on, or removal from, the poles, or when used for any other work subject to 1926 Subpart V. Substations are included in Subpart V, so why do some people say setting steel or regulators is not covered by the exception?

A: You might try to justify substations as being in Subpart V – except for what the substation rules cover in Subpart V. OSHA 1926.966, “Substations,” is not about construction of substations. It is about working in substations. The rule covers minimum approach distances, guarding of live parts, switching and electrical safety. Steel erection, just like concrete work, falls under horizontal standards. 

The logical thinking of very reasonable people regarding this issue often is challenged for sensibility, mostly because of their perspective. For instance, if I can hang a capacitor on a wood pole with a digger derrick, why can’t I hang a beam and capacitor in a substation with a digger derrick? It’s the same thing, it’s a capacitor. The right perspective is that all construction-related lifting of loads by cranes is regulated under 1926.1400, except lifting poles and pole-mounted equipment that are installed using a truck specifically designed for digging and setting poles. 

It’s this easy: If it is not augering holes for poles with a digger derrick, or setting poles with a digger derrick, or hanging equipment on poles with a digger derrick, the piece of equipment is a crane. You can read OSHA’s justification of and limitations on the exemption on page 67315 of Volume 77, No. 218 of the Federal Register, published November 9, 2012 (see www.govinfo.gov/content/pkg/FR-2012-11-09/pdf/FR-2012-11-09.pdf). The section states that “employers cannot use digger derricks within this exemption to perform unrelated tasks such as the construction of a building or the foundation or structural components of a substation … A digger derrick used for this type of construction will still be subject to the requirements in 29 CFR 1926, subpart CC, and operators will have to be certified in accordance with 1926.1427.”

To further frustrate the issue, consider this: Loading a tensioner on a trailer for transport to a job site using a digger derrick is regulated by the crane rules, and the operator is required to be third-party licensed. Loading a 6,000-pound steel pole to do a like-for-like replacement of the same kind of pole is maintenance covered under General Industry rules – not the cranes and derricks rule.

Here is another reason you want to understand and operate true to the exemption. If an operator working under the exemption violates 1910.269’s safe operator expectations, OSHA will void the exemption for that employer and cite unsafe operations under the applicable rules of 1926.1400, including rules found in 1926.1427, “Operator qualification and certification.” To be compliant, employers need to understand the limits of the exemption and effectively evaluate and train their operators. If they are crane operators, they must be properly licensed in compliance with 1926.1427, and they must be evaluated on paper. Records must be kept for all operator evaluations, both for non-certified digger derrick operators and for certified crane operators.

Q: With regard to aerial lifts, can a worker legally transfer from the platform to a steel pole or tower or even the top of a transformer in a substation?

A: The answer is yes, a worker can transfer, but there are certain safety expectations. As to lineworkers in buckets transferring onto poles or towers, there is no prohibition in any rule that we know of. We are aware of a letter from OSHA regarding transferring procedure that clearly does not prohibit transferring. The February 2004 letter is an opinion in response to a query from Michael Kurtgis of USA Airmobile (see www.osha.gov/laws-regs/standardinterpretations/2004-02-02). That question was about using a particular three-legged device to make a tethered transfer from basket to tower; it was determined by OSHA to be a de minimis violation. The transfer was not the issue but rather using the device that tied the worker to both the basket and the tower at the same time, in violation of rule 1926.453(b)(2)(iii).

The cranes and derricks standard both allows and regulates exiting a hoisted platform, which applies to cable-suspended platforms and crane-mounted platforms. Rule 1926.1431(k)(3) requires the following: “Before employees exit or enter a hoisted personnel platform that is not landed, the platform must be secured to the structure where the work is to be performed, unless the employer can demonstrate that securing to the structure would create a greater hazard.” OSHA’s scaffold rules generally cover all personnel lifts and do not address or prohibit transferring off an elevated lift.

Most companies, as well as OSHA, expect fall protection above 4 feet, and OSHA prohibits a worker from being tethered to both a tower and a basket at the same time. If the goal is to prevent falls, tethering to both structures makes sense, and OSHA agrees under its de minimis policy. The purpose of OSHA’s de minimis policy is to satisfy the record recognizing that there is a rule, that the rule was violated but the violation was justified, and that no increased risk was present in violating the rule.

Q: We recently broke a grabber arm while pulling a pole. The arm fell about 25 feet and struck and hospitalized a laborer. His hard hat saved his skull, but the grabber arm fractured his collarbone, shoulder and jaw. OSHA cited us under the General Duty Clause for using the digger derrick boom in a way that the employer knew had a risk of mechanical failure. What is the General Duty Clause?

A: You didn’t mention it for certain, but whenever we hear of such an incident, we generally assume that the crew was rocking the pole to loosen it from the ground for pulling.

In response to your question, the general duty of the employer is to provide a place of employment that is free from recognized hazards that are causing or likely to cause death or serious physical harm to employees. Where OSHA has no particular rule that addresses a workplace condition that resulted in an injury, the agency typically examines how the employer performed hazard analysis of work tasks and reviews the employer’s safety rules, consensus standards and operator manuals to see if the hazard was recognizable and avoidable.

Your issue is not unusual, and both utilities and contractors use booms to rock poles free, which can turn out to be a lot more expensive – if not riskier – than they think. We hear from consultants who often find stacks of pole-pullers stored in warehouses at utilities and contractors. If the companies are not using pole-pullers, they typically rock poles with digger derrick booms to loosen them, which is clearly prohibited by every boom manufacturer. Rocking a pole stresses the boom, the grabbers, the turntable and the turning gear in ways they are not designed to handle. In addition, that also means these companies are forcing the unknown load weight of the pole butt on rigging and a boom that have posted weight load limits, thereby violating very clear OSHA standards on load estimating and planning before lifting.

The solution – reissued policy and accountability – sounds simple. If pole-pullers are not being used, the only option is to dig out the pole butt to completely free it before lifting. We know it’s not that simple, but there are some very good reasons to solve this problem. 

The issue is not just risk to workers who are endangered by the bad practice, nor is it the cost of failures or the premature wear of digger derrick components and the cost of repairs. This practice is a violation of OSHA’s General Duty Clause because the action knowingly violates the manufacturer’s safe operating instructions and standards. Rocking poles and lifting unknown weights also violate OSHA rigging standards for use of slings as well as material-handling standards. The greater issue is the possibility that the employer could have violations assessed under the OSHA 1926.1400 standard regarding operator qualification, rigger qualification, rigging qualification and rigging standards. The reason is that the utility exemption from the 1926.1400 standard relies on compliance with 1910.269 and 1926 Subpart V. If the employer violates the rules of either while operating a digger derrick under the exemption, the exemption will be voided for that employer, and the violations associated with the actions will be assessed under the cranes and derricks standard.

Here are a couple solutions. Use the digger derrick to handle the pole-puller; pole-pullers typically come mounted on digger derrick trucks. Using the digger derrick to handle the pole-puller means the heaviest work the crew will do is hooking up the two hoses and wrapping the chain around the pole. Crews will find that with a little practice, using pole-pullers is an effective method of pulling poles. Keep in mind that poles over 45 to 50 feet usually do have to have some post-hole digger pot-holing to help free the butt.

Thanks for directing your question our way. We hope for the best in your co-worker’s recovery and appreciate the opportunity to share this lesson learned.

Q: We had pulling ropes in the air overnight on a distribution build parallel to a 345-kV transmission line. During the night, two of the ropes came down across a highway and caused a mess. We were told of various solutions, from grounding the rope to grounding the travelers. What do you think the problem was? Is there a solution?

A: There is a solution – and it’s probably not grounding the rope or travelers. In the photo you sent along with your inquiry, we can see that melting of the rope caused it to fail. It appears the rope melted because it was grounded to the steel structure through a traveler that was suspended on a steel sling. The most likely scenario is that induction from the 345-kV line flowed from the rope to ground through the traveler. The rope is high-resistance, so arcing and/or heating at the rope-to-traveler contact point melted the rope.

The problem with synthetic rope is that it is not necessarily insulating, particularly when contaminated by being pulled through aluminum sheaves. If the induction load is high enough, especially with induced current, synthetic rope will ground through the traveler and can cause the rope to burn through, especially if the run stops for any duration in a grounded sheave. Even if you keep the pull moving, an arc can occur along the length of the rope as it runs through the sheave, ultimately resulting in rope failure. We generally hear that 138 kV is borderline for serious induction issues, but it depends on the length of the parallel run and the distance between the rope and the energized line. It’s not very easy to determine how much risk there is.

Some people don’t believe it can happen, but that’s the reason for IEC standard 61328, section 6.2.4, which states: “Where a synthetic rope is used as a pulling rope or as a pilot rope, the use of running earths or stringing block earths is not recommended where it is known there will be induction from adjacent energized lines.” 

In addition, the sheaves don’t have to be intentionally earthed to cause the problem. Simply attaching the sheave to the structure instead of an insulator or allowing the sheave to ride against the structure can have the same effect. The solution is to either use steel rope where grounding is required or isolate the synthetic rope by insulating the travelers, not grounding them.

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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