Incidental line clearance: what a non-utility arborist must not assume

Incidental line-clearance tree trimming is OSHA's preamble term for tree work inside the 29 CFR 1910.269(x) distances that is not directly associated with the line. It falls outside 1910.269, which covers only trimming done for the purpose of clearing the line and on behalf of its operator. Subpart S applies instead, and California's 8 CCR 2950 triggers on proximity alone.

A homeowner calls on a Tuesday about a valley oak limb over the driveway. The limb is dead, it is about eight feet long, and the nearest thing above it is a 12 kV primary running the length of the back fence. Two people show up: one is an ISA Certified Arborist, and one carries a 40-hour line clearance card from two years on a utility contract crew. Nobody from the utility ordered this work. Nobody from the utility knows it is happening.

That job has a name in OSHA's vocabulary. It is incidental line-clearance tree trimming, and almost everything a crew assumes about the phrase is wrong in one direction or the other. It does not mean the work is minor. It does not mean the federal line clearance rules protect you. It does not mean you are free of them either. And in California it does not do the one thing most people reach for it to do.

The phrase is OSHA's own, and it lives in a footnote

"Incidental line clearance" is not a defined term in the Code of Federal Regulations. The word incidental appears nowhere in the regulatory text of 1910.269, 1910.331, 1910.332 or 1910.333. It comes from a preamble, and specifically from footnote 7 of a correcting amendment OSHA published at 80 FR 60033 on October 5, 2015, signed at Washington, DC on September 28, 2015 by Assistant Secretary David Michaels and effective on the day it published.

The footnote says what OSHA meant by it:

Throughout this preamble, OSHA refers to any tree trimming activities performed on a tree or brush that is closer to an electric power generation, transmission, or distribution line or equipment than the distances specified in the definition of "line-clearance tree trimming" in existing Sec. 1910.269(x) as "incidental line-clearance tree trimming" when the tree trimming activities are not directly associated with the lines or equipment.

Read that twice, because it is doing two things at once. It concedes that the work is inside the distances. Then it says the work is not directly associated with the line. The phrase exists to name that gap, nothing more.

It is an explanation of a scope limit, not a tier, not a status, and not a qualification anybody can hold. A course, a card or a contract that describes itself with the phrase is describing where the standard stops applying, which is a different thing from describing what its holder is allowed to do.

The definition catches you; the scope does not

Two provisions, ten lines apart, disagree about the oak limb, and the disagreement is deliberate.

The definition in 1910.269(x) is measured in feet. It captures pruning, trimming, repairing, maintaining, removing or clearing of trees within 10 feet of supply lines at voltages to ground of 50 kV or less, with the distance growing above that. OSHA said plainly in the 2015 preamble what follows from writing a definition that way:

any trimming or other maintenance of any tree or brush that is within the specified distances of an electric power line is line-clearance tree trimming, irrespective of the purpose of the activity or the occupation of the worker.

By that definition, the dead limb over the driveway is line-clearance tree trimming. So is a fruit tree pruned under a service drop.

The scope provision is measured in relationships. The introductory text of 1910.269(a)(1)(i)(E) reaches only line-clearance tree trimming of this description:

performed for the purpose of clearing space around electric power generation, transmission, or distribution lines or equipment and on behalf of an organization that operates, or that controls the operating procedures for, those lines or equipment.

Two conditions, joined by "and," and the homeowner's removal satisfies neither one. The note OSHA added to the definition in 2015 spells the result out: trimming performed on behalf of a homeowner or commercial entity other than such an organization "is outside the scope of this section."

So the crew in the backyard is doing line-clearance tree trimming that 1910.269 does not cover. What the standard does to a crew once the work is inside its scope, including the tier that paragraph (r)(1) was written for, is a different page and a different day.

One piece of history is worth carrying, because a lot of training material predates it. OSHA announced this reading in a memorandum dated February 18, 2015 to its Regional Administrators, signed by Deputy Assistant Secretary Dorothy Dougherty and Directorate of Enforcement Programs Director Thomas Galassi, seven months before the regulatory text caught up.

That memo announced an interim enforcement policy: no citations under 1910.269 for trimming that fails either condition, but citations still available "under any other standards that apply," naming 1910.268 and 1910.331 through 1910.335. The memo is still on OSHA's site, and it now carries the banner "NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy," because the October 2015 amendment made it unnecessary. Cite the rule, not the memo.

The two conditions, and the jobs that cross them

The conditions are easy to state and easy to misapply, so here they are against real work.

A removal ordered by a property owner is out, even if the tree is touching the primary and even if you prune the conductor side first to get the piece off safely. Your purpose is removing the tree.

A subcontract for the utility is in, all of it. If a line clearance contractor hands your crew two spans during a storm restoration, the work is for the purpose of clearing the line and on behalf of the organization that operates it. Both conditions close, and the whole of paragraph (r) arrives with them, along with the training, host and contract employer information transfer, medical services, job briefing, personal protective equipment and mechanical equipment paragraphs listed in (a)(1)(i)(E)(2). Nobody gets to take the parts of 1910.269 they like.

The other line on the pole decides its own regime. OSHA's preamble uses the case directly. An employee trimming away from telephone or cable television lines that happen to be near a power line is doing work "directly associated with communications lines, not electric power lines, and is covered by Sec. 1910.268, not Sec. 1910.269."

Footnote 6 of the same document adds that under 1910.331(c)(2), clearing space around communications lines is exempt from 1910.331 through 1910.335 when performed by qualified persons. One pole with a primary at the top, a neutral, secondaries and a cable drop at the bottom can therefore sit under three different standards depending on whose space you were hired to clear. The conductor does not care, and neither will the compliance officer if you guessed.

What governs instead, and the paragraph written to say so

The same October 2015 amendment that closed the 1910.269 door opened the other one explicitly. It revised 1910.331(b) to name two kinds of work that 1910.331 through 1910.335 also cover:

(1) Work performed by unqualified persons on, near, or with the installations listed in paragraphs (c)(1) through (4) of this section; and (2) Work performed by qualified persons near the installations listed in paragraphs (c)(1) through (c)(4) of this section when that work is not on or directly associated with those installations.

Distribution lines are installations under (c)(1). That is the whole answer to "what applies instead," and OSHA wrote subparagraph (2) because the previous text left it to be inferred. In the same stroke Note 3 to (c)(1) was rewritten so that line-clearance tree trimming counts as directly associated work only "when that work is covered by § 1910.269."

Then comes the part that surprises employers. 1910.332 requires electrical safety training for employees facing a risk of shock, and it points at Table S-4. That table is a list of twelve occupational categories written in 1990:

• Blue collar supervisors

• Electrical and electronic engineers

• Electrical and electronic equipment assemblers

• Electrical and electronic technicians

• Electricians

• Industrial machine operators

• Material handling equipment operators

• Mechanics and repairers

• Painters

• Riggers and roustabouts

• Stationary engineers

• Welders

Tree work is not on it. Arborist is not on it. Neither is line clearance.

The duty arrives through the sentence after the table instead: "Other employees who also may reasonably be expected to face a comparable risk of injury due to electric shock or other electrical hazards must also be trained." An employer who reads the table as a list and stops has just concluded that a climber ascending into a canopy with a 12 kV primary in it needs no electrical training at all. A painter on a ladder is named; the climber is not.

For anyone the employer intends to treat as a qualified person, 1910.332(b)(3) sets three items: telling exposed live parts from the rest of the equipment, working out the nominal voltage of those parts, and knowing which 1910.333(c) clearance distance goes with which voltage.

Note 1 makes the list constitutive rather than advisory, so a person without that training is not a qualified person for these sections whatever the job title says. Paragraph (c) allows classroom or on-the-job training and pegs the degree of it to the risk, and says nothing at all about a certificate. What the file has to hold to make a qualification stand up is the other half of that sentence.

There is no OSHA standard for tree care as a trade. OSHA's June 30, 2021 inspection guidance for tree care and tree removal operations says as much in its own way. The hazards are addressed by scattered general industry standards in 29 CFR 1910, with the General Duty Clause held in reserve for what those standards miss. Falling outside 1910.269 does not land you somewhere with fewer rules. It lands you somewhere with less organized ones.

Deenergized and grounded, or other protective measures, before work is started

The operative sentence for the backyard oak is the first one in 1910.333(c)(3):

If work is to be performed near overhead lines, the lines shall be deenergized and grounded, or other protective measures shall be provided before work is started. If the lines are to be deenergized, arrangements shall be made with the person or organization that operates or controls the electric circuits involved to deenergize and ground them.

Three things are decided by that paragraph, and none of them is decided by the crew alone.

You cannot make the line safe yourself. The note immediately after it says that installing insulating devices on overhead transmission or distribution lines is 1910.269 work, not Subpart S work, and that under 1910.333(c)(2) unqualified persons are prohibited from performing it. Rubber line hose bought online and thrown over a primary is not "other protective measures." It is an unqualified person working on an energized line.

Your pole saw counts. The note to 1910.333(c)(3)(i)(B) is one sentence: "For voltages normally encountered with overhead power lines, objects which do not have an insulating rating for the voltage involved are considered to be conductive." A fiberglass pole pruner with no dielectric rating and no test history is a conductive object, and the distance is measured from its tip, not from your hands.

The truck has its own number. Under 1910.333(c)(3)(iii)(A), any vehicle or mechanical equipment capable of having part of its structure elevated near energized overhead lines is operated so that 10 feet is maintained. In transit with the structure lowered, that drops to 4 feet.

It drops to the Table S-5 distance only where the equipment is an aerial lift insulated for the voltage involved and the work is performed by a qualified person, which is two conditions, not one. A knuckleboom grapple truck parked under a span is inside this paragraph whether or not anyone is in a bucket.

In practice the first call is short. PG&E's tree safety page says that only trained, line clearance-qualified personnel with the right tools should do tree work near powerlines, and tells customers to keep the body and tools at least 10 feet away.

It points them to Start/Stop Service for a free temporary service disconnect, with 1-800-564-5080 and treesafety@pge.com for tree safety work. For a service drop, a temporary disconnect is a real and cheap answer. For the primary above it, a disconnect is not on the menu and the conversation is about a planned outage, a cover-up crew, or the utility's own contractor taking the tree.

California never wrote the gate

Here is the assumption that actually hurts people, and it is the one this page exists to break.

The federal analysis above turns entirely on who ordered the work. California's tree trimming article turns on nothing but distance. 8 CCR 2950(a) switches Article 38 on by proximity and by nothing else:

This article shall apply to all line clearance tree trimming operations performed in the vicinity of exposed energized overhead conductors and equipment where any part of the employee's body, tools or equipment being used, or parts of trees being worked upon, is likely to come within the distances specified in Table 1 of this section.

There is no purpose condition in that sentence. There is no on-behalf-of condition. There is no homeowner note, no residential carve-out, and nothing corresponding to footnote 7.

And 8 CCR 2951(b) closes it: only qualified line clearance tree trimmers, or trainees under their direct supervision and instruction, may perform line clearance tree trimming operations as described in section 2950. In California that is a staffing rule, not a permission slip, and it reaches the residential crew in the backyard exactly as it reaches the utility contractor two streets over.

What Table 1 requires, who it binds, and the three exceptions printed underneath it is the page to read next, along with which credential a residential company can realistically hold and what the rest of section 2951 requires of the operation.

California operates an approved state plan, so a Cal/OSHA inspector writes Title 8 and not Part 1910. The upshot is blunt: the federal carve-out is real, and it is not a defense at a California job site. A crew that tells an inspector the work was incidental line clearance has said something true about 1910.269 and nothing at all about Article 38.

The call you owe before anyone ties in

Article 37 of the same High-Voltage Electrical Safety Orders carries a duty that has nothing to do with tree work in particular and everything to do with this job. 8 CCR 2948 is one sentence long:

When any operations are to be performed, tools or materials handled, or equipment is to be moved or operated within the specified clearances of any energized high-voltage lines, the person or persons responsible for the work to be done shall promptly notify the operator of the high-voltage line of the work to be performed and shall be responsible for the completion of the safety measures as required by Section 2946 (b) before proceeding with any work which would impair the aforesaid clearance.

Two duties, not one. Notify the operator, and be responsible for the completion of the safeguards. The second is the one that catches people. Leaving a voicemail is not a safeguard. The obligation to see the measures completed sits on the person responsible for the work, which on a residential job is the tree company, not the utility and not the homeowner who signed the estimate.

8 CCR 2946 supplies the measures and the arithmetic. Its subsection (b)(2) prohibits handling tools, machinery, materials, structures or scaffolds, "or any other activity where any parts of the above or any part of an employee's body" comes closer than Table 1, which is 6 feet at 600 to 50,000 volts.

Table 2, for material storage and boom-type lifting or hoisting equipment, is 10 feet across the same band. Subsections (b) and (d) were last amended by a filing of February 27, 2018, operative April 1, 2018. And subsection (d) settles the argument about whether a line is hot:

Any overhead conductor shall be considered to be energized unless and until the person owning or operating such line verifies that the line is not energized, and the line is visibly grounded at the work site.

Verified by the owner, and visibly grounded, at the work site. A dispatcher's assurance over the phone satisfies half of that test.

None of this is knowable from the ground. Two authors writing in Tree Care Industry Magazine on June 1, 2023, Geoff Kempter and Stephen Hilbert, put the practical problem in one line. The facilities are not labeled with the voltage, and "the only way to be certain about voltage in a given location is to contact the utility-system operator." The regulation that requires you to know the voltage and the field condition that prevents you from knowing it resolve at the same phone number.

It is also a misdemeanor

California put a version of this rule in criminal law in 1947 and never took it out. Penal Code section 385 defines high voltage in subdivision (a) as more than 750 volts, and then:

Any person who either personally or through an employee or agent, or as an employee or agent of another, operates, places, erects or moves any tools, machinery, equipment, material, building or structure within six feet of a high voltage overhead conductor is guilty of a misdemeanor.

Any person. Not any employer, and not any employee of a covered industry. A sole proprietor with a saw is inside subdivision (b), and so is the customer who decided to help.

Notice what the list covers and what it does not. Tools, machinery, equipment, material, a building, a structure. A person's own body is not in it, which is precisely the gap 8 CCR 2946(b)(2) fills with "or any part of an employee's body." The Penal Code governs the object; Title 8 governs the worker.

Subdivision (c) requires a durable warning sign legible at 12 feet on any crane, derrick, power shovel, drilling rig, hay loader, hay stacker, pile driver or similar apparatus, reading "Unlawful to operate this equipment within six feet of high voltage lines."

8 CCR 2947 requires a sign on the same list of machines, legible at the same 12 feet, reading "Unlawful To Operate This Equipment Within 10 Feet Of High-Voltage Lines of 50,000 Volts Or Less." Six feet in one, ten feet in the other, both mandatory, both on the same grapple truck. The safety order matches its own Table 2 for boom equipment; the Penal Code has said six since 1947.

And subdivision (d) exempts "the construction, reconstruction, operation or maintenance of any high voltage overhead conductor, or its supporting structures or appurtenances by persons authorized by the owner." That is the on-behalf-of test again, in a criminal statute, seventy years before OSHA wrote it into 1910.269.

8 CCR 2949 ties the two together from the Title 8 side, exempting sections 2946 through 2948 for qualified electrical workers authorized by the owner, and for qualified persons working "in accordance with Penal Code Section 385D." Authorization by the line's owner is what moves you across every one of these lines. Nothing about skill, tenure or a card does it.

Where this is genuinely unsettled, and who decides

Three questions come up on real jobs and the text does not answer them.

Is a tree company's boom truck a "similar apparatus"? Both Penal Code 385(c) and 8 CCR 2947 list cranes, derricks, power shovels, drilling rigs, hay loaders, hay stackers, pile drivers "or similar apparatus." Neither names a knuckleboom log loader or a crane truck used for removals, both of which are capable of vertical, lateral and swinging motion and are the reason those sections exist.

The employer makes the call in the first instance, a Cal/OSHA compliance officer tests it at an inspection, and the Occupational Safety and Health Appeals Board resolves it if the citation is contested. Posting the sign costs less than the argument.

Is a covered service drop "guarded"? The federal distances in 1910.333(c)(3)(i) apply to "unguarded, energized" lines. 1910.399 defines guarded as covered, shielded, fenced or enclosed by suitable covers, casings, barriers, rails, screens, mats or platforms "to remove the likelihood of approach to a point of danger or contact by persons or objects." The same section distinguishes a covered conductor, encased in material not recognized as electrical insulation, from an insulated conductor, which is.

Weatherproof covering on a triplex drop is the first of those, not the second, and nothing in Subpart S says a covered conductor is thereby guarded. Read with the note that unrated objects are considered conductive, the safe reading is that a covered drop is an energized, unguarded conductor. The employer who wants to read it the other way is making a determination that a compliance officer will test, on a line whose voltage the employer cannot verify without calling the operator anyway.

Why does the standard ask less of the crew with less experience? Kempter and Hilbert raise this one directly in the article cited above, noting that a second qualified line-clearance arborist must be on site at all times for utility work. They then ask why that requirement would not apply to incidental line-clearance arborists, "who in general have less experience."

It is a fair question and the answer is jurisdictional rather than technical: 1910.269(r)(1) was written for employers inside a utility's system of job briefings, voltage information and standby, and Subpart S was written for everyone else. Nobody harmonized them. The consensus standard for the trade, ANSI Z133, is where the industry answers the question OSHA left open, and it is not the enforcement document in California. The pre-work brief is where the gap gets closed, or does not.

The oak limb over the driveway is still dead. Removing it is lawful, ordinary work, and none of the above forbids it. What the crew cannot do is start it on the strength of a phrase from a 2015 preamble, a card from a previous employer, and a guess about the conductor.

Further reading

• 29 CFR 1910.269(r): the three tiers, and what each one may approach: What the federal standard does with a crew once the work is inside its scope.

• Table 1 of 8 CCR 2950: the minimum approach distance, and who owes it: The California distance a person who is not a qualified line clearance tree trimmer owes, and the three exceptions to it.

• Qualified line clearance tree trimmer versus qualified tree worker: The two California credentials, and which one a residential crew can realistically hold.

Frequently asked questions

What does incidental line clearance mean?

It is OSHA's phrase for tree work close enough to a power line to meet the definition of line-clearance tree trimming in 29 CFR 1910.269(x), but not directly associated with that line. OSHA defined its own usage in footnote 7 of the correcting amendment published at 80 FR 60033 on October 5, 2015: tree trimming activities on a tree or brush closer to a line than the distances in the definition, when those activities are not directly associated with the lines or equipment. The phrase does not appear in the regulatory text of 1910.269, 1910.331, 1910.332 or 1910.333. It is preamble vocabulary that explains a scope limit, not a category that confers any qualification.

Does 29 CFR 1910.269 apply to a residential tree company working near a power line?

No, provided the work fails either condition in 1910.269(a)(1)(i)(E). That paragraph covers line-clearance tree trimming performed for the purpose of clearing space around the lines and on behalf of an organization that operates, or that controls the operating procedures for, those lines. The note to the definition of line-clearance tree trimming in 1910.269(x) says directly that trimming performed on behalf of a homeowner or commercial entity other than such an organization is outside the scope of the section. The work is then covered by 29 CFR 1910.331 through 1910.335, and possibly 1910.268 if the tree is being cleared from a communications line.

How close can a non-utility arborist get to an energized conductor?

Federally, 29 CFR 1910.333(c)(3)(i)(A) gives an unqualified person 10 feet at voltages to ground of 50 kV or below, measured to the longest conductive object that person may contact, and 1910.333(c)(3)(ii) gives a qualified person the Table S-5 distances, which are 2 feet 0 inches over 2 kV and not over 15 kV. In California the enforced number is Table 1 of 8 CCR 2950, which is 10 feet for everyone who is not a qualified line clearance tree trimmer or trainee from 0.0 kV through 50.0 kV, subject to the three exceptions printed in that section.

Do I have to call the utility before working near its line in California?

Yes. 8 CCR 2948 requires the person or persons responsible for the work to promptly notify the operator of the high-voltage line when operations are to be performed, tools or materials handled, or equipment moved or operated within the specified clearances, and it makes that same person responsible for the completion of the safety measures required by 8 CCR 2946(b) before proceeding. Under 8 CCR 2946(d) the conductor is treated as energized until the person owning or operating the line verifies that it is not and the line is visibly grounded at the work site.

Is working close to a power line a crime in California?

It can be. California Penal Code section 385(b) makes it a misdemeanor for any person to operate, place, erect or move any tools, machinery, equipment, material, building or structure within six feet of a high voltage overhead conductor, with high voltage defined in subdivision (a) as more than 750 volts. Subdivision (d) exempts work on the conductors and their supporting structures by persons authorized by the owner, which is the same on-behalf-of idea that limits 1910.269, written into criminal law in 1947.