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Don’t Abuse OSHA’s Digger Derrick Exemption

This isn’t the first time – and I suspect it won’t be the last time – that I have addressed the question of what work can be done under the digger derrick exemption found in OSHA’s Cranes and Derricks in Construction standard (29 CFR 1926 Subpart CC). The issue has come up constantly since the matter of the digger derrick exemption was resolved, and just recently I once again received considerable pushback to an answer I provided on the topic for Incident Prevention magazine’s Q&A section.

Before we go any further, I want to define some terms I will use in this article for brevity’s sake. “Subpart CC” or “CC” refers to OSHA’s Cranes and Derricks in Construction standard. “CDAC” refers to the rulemaking committee that established the proposed standard in collaboration with OSHA’s Directorate of Construction. “DD” refers to a digger derrick, which is a truck-mounted extendable hydraulic boom equipped with an auger, a transferable pole grabber, a winch and typically a fiberglass insulating end extension.

An important aspect of the DD as far as OSHA is concerned is that the DD was purpose-designed by the utility industry to set wood poles. As a boom truck typically lift-rated in the 10- to 30-ton range, the winch and boom can be used to perform other lifts. However, according to utility industry research, over 90% of lifts performed by a DD are for setting electric utility poles and the apparatus typically mounted on those poles.

Subpart CC History
It has now been more than 15 years since the original Subpart CC standard was published, so a review of the subpart’s history and resulting utility litigation is probably useful. Until the Subpart CC standard was published, operating rules for cranes and DDs were spread across the OSHA General Industry and Construction standards. No specific training or licensing requirements existed for crane operators. There were rules but no detailed safety procedures for operating a crane in or near an energized environment, and there were no specific actions or activities required to establish stable ground under a loaded crane for effective support. No doubt, the Subpart CC rules were needed because the lifting industry as a whole – outside the utility sector – had a pretty poor safety record.

The issues with the CC rules for the power-line industry were significant. In the construction lifting industry at large, formal licensing under the CC rules found at 1926.1427 only affected one worker, the crane operator, among the 200 or more various craftspeople on some larger construction sites. In the utility industry, because journeymen lineworkers are skilled equipment operators, the original licensing requirements applied to every journeyman craft worker; that’s about four in six field personnel covering some 120,000 lineworkers in the U.S. to the tune of about $21 million annually. So, initially, OSHA did offer a narrow exception for setting poles, but it wasn’t enough.

The industry turned to our very effective industry support partners as well as Edison Electric Institute, a lobby organization, which was then under the leadership of Chuck Kelly. EEI was effective in demonstrating that the industry had a significantly disproportionate burden in complying with the new Subpart CC rules. They also demonstrated that the disproportionate burden was unnecessary considering the utility industry’s very good record of safety when using DDs. EEI and the utility industry were successful, and the exceptions contained within Subpart CC were defined and established. Here is where the problems began.

Understanding the Exemption
As to the exemption, I recommend that you read the preamble discussion OSHA published with the DD exemption revision in Subpart CC; it is available at

As readers will see, in a specific discussion about transformers, OSHA limited use of the DD exemption to transformers and related equipment that is mounted/hung on the pole. In the revision to the exemption, after negotiations with EEI, OSHA very narrowly added padmount transformers as an exemption. A key part of the EEI/OSHA negotiation lies in the very specific terms discussed. The persuasion for OSHA was in EEI’s comments that a padmount transformer weighs the same as an aerial transformer, is often set in the same vicinity of the pole and is installed by the same crew.

Now the question is, what constitutes a padmount transformer in the exemption? That is answered by framing the discussion as to the weight of an aerial transformer being near the same as a padmount. That would seem to limit the DD exemption expansion to single-phase pads. When we set an aerial three-phase bank, we typically hang three single-phase transformers. We can bank two of the three single-phase URD padmount transformers together, and I have, but it is more common to install a three-phase padmount, which is three times heavier than an aerial transformer. Considering the terms of the EEI/OSHA negotiation and the preamble discussion, a three-phase pad would exceed the DD exemption.

Would you get caught using a competent, qualified operator who is not Subpart CC licensed to set a three-phase pad? That’s not likely under present conditions. OSHA has not established targeted enforcement of the Subpart CC digger derrick exemption – yet. The agency would only initiate an investigation of an operator’s license status if they were called to do an inspection related to a fatal incident or a complaint, or they may self-initiate an inspection if they were driving by and observed a condition that presented an immediate danger to life or health. But being unlikely to get caught is not justification for exceeding the provisions of the DD exemption. The rule is very narrowly written and defined. Decision-makers who read the preamble should heed the warning included in OSHA’s comments about arbitrarily expanding the DD exception. The agency did not want to create nor expand the exemption. In doing so, they issued a warning to the industry not to try to expand the exemption beyond those terms found in the preamble. Failure to heed that warning could inspire OSHA to revisit the exemption and eliminate it altogether.

Clarifying OSHA’s Language
Another question I regularly receive from readers is about this sentence from the preamble: “OSHA is revising the exemption in existing 29 CFR 1926.1400(c)(4) to include within the exemption the phrase ‘any other work subject to subpart V of 29 CFR part 1926’ as proposed.”

Again, in the preamble, OSHA explained the phrase “any other work” as follows: “This revision expands the exemption to remove from coverage under subpart CC of 29 CFR part 1926 the types of non-pole, digger-derrick work described by EEI.” In other words, “any other work” as described by EEI in the negotiations. That described work was strictly limited to single-phase padmount transformers.

Here’s one more thought regarding how OSHA preceded their warning using the phrase “OSHA acknowledges.” Some have lobbied that the statement means OSHA “knows” we can use the DD exemption for other tasks, but that is incorrect. What that reference addresses is OSHA’s concern acknowledging random expansion of the exemption by utilities justifying additional uses of DDs outside the narrow exemption. When OSHA brought up the concern, EEI convinced them that the industry could employ DDs for lifting in substation construction, but it was not likely because most substation construction lifting required use of conventional truck cranes for the necessary reach and capacity. That satisfied OSHA, but they added the following warning at the end of the record to keep us honest:

“OSHA acknowledges that revising the exemption would extend the digger-derrick exemption to include some work at substations. However, EEI indicated that the employers in the electric-utility industry limit such uses to assembly or arrangement of substation components, and that these employers use other types of cranes instead of digger derricks to perform lifting and installation work at substations (see OSHA-2012-0025-0005: Jan. 2011 EEI letter). If OSHA finds that employers are using digger derricks increasingly for other tasks, the Agency may revisit this issue and adjust the exemption accordingly.”

In the final part of OSHA’s warning, the agency clarified post-incident investigation citations for a utility that was found violating the DD exemption, stating the following: “If an employer uses a
digger derrick for subpart V or telecommunications work without complying with all of the requirements in subpart V or Sec. 1910.268, then the work is not exempt and the employer must comply with all of the requirements of subpart CC of 29 CFR part 1926. This clarification is consistent with OSHA’s explanation of the exemption in the preamble of the final rule (see 75 FR 47925-47926).”

In simple terms, if a utility is found noncompliant with the rules for DD operation, the exemption is invalidated, and the operation being cited by OSHA will be cited under all of the applicable rules of Subpart CC.

Why an Exemption Expansion?
OSHA uses the preamble text to support its citations. The preamble is pretty clear in this case. So, if OSHA didn’t really want to expand the exemption, why did they do it? There were likely several reasons, including avoiding another round of legal actions after failing against EEI in the minimum approach distance and transient overvoltage legal challenges to the 2014 final rule changes.

It is also reasonable to assume that OSHA’s intent was tight control over the entire lifting community. OSHA never wanted to establish an exemption and considered a crane to be a crane to be a crane, and that all crane operators should be specifically licensed to establish safety in lifting.

Based on EEI’s petition, OSHA found that the CDAC was very poorly represented by the utility and communications industry. The agency also discovered that the CDAC studies failed to recognize that utility industry incidents were nowhere near the level of incidents in the general lifting community. Further, OSHA found out that the financial obligation for utilities to license DD operators, who had an impressive safety record, was disproportionate to the general lifting community. And OSHA realized that 95% of the lifts performed by DDs – a number contributed by the IBEW – were very narrowly related to poles and pole-mounted equipment.

Hence, OSHA and EEI agreed to narrowly limit the exemption to the 95% of work for which DDs were specifically designed: poles and associated equipment mounted on those poles. There is no justification to assume that anything other than a transformer fits into the exemption.

In judging the issue of what is permitted in the DD exemption, it’s simply comparing the activities: flying a rack or bundle of travelers to a pole-top; flying in a 20-foot laminated transmission crossarm; hanging a three-phase transmission isolation switch or distribution regulators; setting rebar or steel in a substation; and comparing that activity to hanging a single-phase transformer. That is how compliance officers were instructed to look at it. If it’s not as simple as hanging a pot, it’s not allowed. That was the basis for adding padmounts to the exemption. Readers will notice that in the discussion of padmounts, nobody in the preamble record ever discussed their size/type. However, they did discuss weights, using the comparison of a single-phase transformer. So, from that perspective, we can correctly apply single-phase padmounts within the exemption. And using that logic, we can also assume a weight of fewer than 500 to 700 pounds, even though those particular values are not debated.

Final Note
A final note: The DD exemption only applies to construction qualified by OSHA as new installations or upgrading of strength or capacity of existing facilities. If a utility is merely replacing like-for-like facilities or performing maintenance on a structure using a DD, the work is not covered by Subpart CC, and the operator only needs to be qualified by the employer.

I doubt there will ever be a test case because as an industry we have an exceptionally good record with DD use. The issue is that if the industry wants to cheat, they should do it with a clear understanding of what the rules are and what the consequences could be – not just for the employer but for the whole industry.

About the Author: After 25 years as a transmission-distribution lineman and foreman, Jim Vaughn, CUSP, has devoted the last 27 years to safety and training. A noted author, trainer and lecturer, he is a senior consultant for the Institute for Safety in Powerline Construction. He can be reached at


Jim Vaughn, CUSP

After 25 years as a transmission-distribution lineman and foreman, Jim Vaughn, CUSP, has devoted the last 24 years to safety and training. A noted author, trainer and lecturer, he is a senior consultant for the Institute for Safety in Powerline Construction. He can be reached at