California Regulations for Overhead Electrical Utility Vegetation Clearance from Power Lines

This huge stump was a 9 foot diameter California Bay Laurel.  This remarkable heritage tree was growing on the opposite side of the road from a PG&E distribution circuit that followed the road.  It presented little to no threat to that electrical circuit and it grew on public park land.  PG&E began this type of tree destruction about fifteen years ago and has demolished hundreds of thousands of trees, possibly millions. 

This destructive practice accelerated dramatically in 2018 after the CPUC claimed that their rule modification would have no significant impact on our environment.

Equipped with the information in this article, you will be in a stronger position to protect your property and your beautiful trees.

You will have to assert yourself. PG&E contractors are trained to be polite, most are. Walk out and ask the tree company employees what they’re doing. Speak to the crew leader. Tell them to be specific about what trees they intend to cut down or trim. If they say “trim” ask where and how much.

If you disagree, tell them so. Remember, a utility Right of Way is probably land that belongs to you. A utility company has an easement to use your land. But they only have the right to use your land for a specific and limited purpose. Their easement is probably no more than 20 feet wide for overhead power lines. This width varies by county and the year the easement was recorded, if that easement was ever actually recorded.

If you do not receive clear answers to your questions from the contractor, you would not be the first person to tell these people to leave. These are all your decisions to make, of course. Negotiations will likely follow.

[Unfortunately this website cannot offer informed legal advice.] We suspect that many of the legal questions involved have not been tested in a court of law.

You can tell the contractor to send a PG&E representative to talk to you about what PG&E intends to cut.  However you will likely be told by PG&E’s contractor that they, the contractor, are who you need to discuss the issue with.  Nevertheless, tell either PG&E or their contractor that if they want to cut trees on your land,  they need an appointment with you, so you can be present when the contractor is cutting trees.

This is crucial.  It’s a mistake to expect PG&E contractors to be reliable with you. They are under pressure from PG&E, and they certainly do not work for you.  Many people have returned home after time away to find their property mangled and strewn with logs from live destroyed trees.

PG&E has destroyed thousands of people’s trees, that in years past were not regarded as a problem. PG&E is huge, but it is also a company in jeopardy. Pacific Gas & Electric has been criminally convicted of multiple crimes. As of December 2021 the company is facing additional prosecution by the Shasta County District Attorney.

Vegetation Clearance Regulations

The rules for vegetation clearance between trees and overhead utility circuits are primarily the responsibility of the CA Public Utilities Commission (CPUC). However CalFire/CDF (CA Department of Forestry and Fire Protection) has some PRC (Public Resources Code) regulations that also apply.

At your home the utility circuit will usually be a Distribution Circuit operating at less than 60,000 volts (60kV). The average such circuit is often 12,000 volts. Distribution circuits are the lines of power poles that connect directly to homes and businesses. Transmission circuits operate at 60,000 volts to 500,000 volts, generally speaking. Some transmission circuits are hung from wooden power poles by PG&E. These circuits do not connect directly to houses. But they may run across your back yard or be suspended from tall steel lattice towers that cross large scale terrains leading from energy generation sites like hydropower dams and connecting to sub-stations. Occasionally a line of power poles contains both distribution and transmission cables on the same poles.

Most often the rules you need to understand, as a home or landowner, are those that apply to distribution voltage circuits. If you know these CA regulations, you will be in a much better position to protect your land and your trees from PG&E and its contractors. PG&E has chosen to focus on tree removals. Their plans, generally referred to as “system hardening”, for upgrading their old equipment to make it fire-safe, are unconvincing to us. 

You need not be the victim of PG&E’s choice to use outdated and worn out equipment.

Synopsis of CPUC and CalFire Rules for Tree Clearances

Here is a brief synopsis of the CPUC and CalFire rules for the tree clearances applying to the circuit on your street or road. Remember, this is a synopsis. There may be small errors in these numbered paragraphs because the point here is to keep this as simple as we can. This is not the entirety of the regulations that apply in every situation. That will be available later in this article.

Here is a link to the CPUC map of High Wildfire Threat Districts:

(1) For most Distribution Circuits in High Wildfire Threat Districts operating at less than 60,000 volts, the distance or clear space between the uninsulated conductor cable/wire and a tree or branch must be maintained at a distance of at least 4 feet radial (a clear circle around each of the 3 conductors) to last roughly a year until another vegetation clearance inspection takes place.   

You may have been told this distance is at least 12 feet. This is not true. 12 feet is specifically a “recommendation” or a “guideline” of the CPUC contained in Rule 35 of General Order 95.  [In our opinion, 12 feet of vegetation clearance does not “read” as a state administrative law regulation.  This is a contradiction in General Order 95.  But we cannot provide a legal opinion on this issue.]  

[The following is mere supposition on our part:  We suspect the reason that 12 feet clearance was not written as a regulation into Table 1 by the CPUC is that the utilities did not want to be liable for wildfire ignitions in situations where they had not cut back 12 feet.] Ironic? There’s no lack of dark irony in this story. On a regular subdivision street, not delineated in the CPUC 2017 High Wildfire Threat District map, this clearance distance is 18 inches.

(2) Large tree trunks and large strong branches that do not move in high winds require a minimum of 6 inches clearance from bare wire. Spacer Cable needs no specific vegetation clearance. Spacer Cable systems are fully insulated and very strong. It’s unlikely you will ever see PG&E use this superior conductor cable system. We have only seen PG&E use Spacer Cable over railroad crossings.

(3) If you are lucky enough to have insulated or “covered” main distribution power conductors on your street or road, then the only clearance standard for vegetation is that a branch does not rub against or abrade the conductor’s insulation.  The branch must not touch the conductor cable. 

(4) If a tree shows clear signs of damage or decay that may cause the tree to fall into the power line, and also if a weakened tree leans toward the power line, or if the tree or branch is dead, then that tree or branch should be removed.   

A special problem here is that many California hardwoods grow outward sideways “looking for” sunlight.  This is true of many trees that are healthy and strong.  Large conifers can correct their own lean over time, because these trees always seek to grow vertically.  In fact this ability to correct for balance is inherent with most California conifers.  Old trees can often adjust to landslides in the hillslopes they grow upon.

(5) If you live in a rural area and the power pole near your house is an end pole (end of the circuit) or if the circuit turns direction, then CalFire requires this pole to have a 10 foot cleared area around the pole. This rule also applies to poles with transformers, fuses, switch gear or other extra equipment. This regulation applies to lands where CalFire has primary responsibility for firefighting and is forest, brush or grass covered land. We do not think that this rule applies to a regular subdivision street in a town or city with its own fire department. However this is not made clear in these regulations. CalFire has firefighting responsibility for what are called State Responsibility Areas or SRAs.

Is this a State Regulation or PG&E’s Plan?

These issues have become confused because PG&E makes up its own standards for vegetation clearance. These PG&E specific standards are often not found in CA State Regulations. PG&E’s “standards” may be in their Wildfire Mitigation Plan, or just in a brochure mailed to your home.  

PG&E does not have the authority of a government agency. This problem with PG&E making up its own rules accelerated in 2018 when PG&E began its Enhanced Vegetation Management (EVM) program. EVM is a major part of PG&E’s Wildfire Mitigation Plans produced during a CPUC Proceeding. 

Many thousands of old trees have been destroyed after PG&E began to pressure homeowners to cooperate with their EVM program. A PG&E executive recently acknowledged that vegetation management is not enough to prevent wildfires, because debris blows into their lines from long distances away from the power lines. This is further evidence that upgrades to utility equipment are necessary. This however is not the story you will be told when contractor trucks show up at your house with orders to fell the trees on your land.

Important safety details to understand 

Every home “service drop” has two black insulated conductors and one bare “neutral” wire (a twisted aluminum cable) that connects to your house and is grounded. The black insulated wires in this service drop each carry 125 volts, the same voltage as the wall outlets in your house. However the power potential of this service line is huge. Service drops are dangerous. This “service drop” leads from a transformer on a nearby power pole. Several houses may be supplied from one transformer over what are called “secondaries.” Secondaries are strung below primary voltage cables.  

The main power conductors run from pole to pole only. They are usually bare, uninsulated, and they carry far higher voltages than the “service drop” to your house. These main conductors are very dangerous. Never approach a downed powerline. Many fallen power lines will remain energized “hot”. We have not witnessed PG&E using readily available equipment to protect against the problem of downed energized wires (unless they have instituted Fast Trip or EPSS; however we don’t know if Fast Trip settings will de-energize fallen wires). 

Call 911, stand back and wait for the fire department. PG&E will eventually arrive to de-energize the circuit. Try to keep other people and vehicles away from this downed power line until the fire department is on site to handle the risks. If you see this line flash arcing like fireworks, it can kill you. This is called a high impedance arc fault. Even if you don’t see arcing, stay away! That line could still be hot.

Below are what we understand to be the full rules for overhead powerline vegetation clearances in California

CPUC General Order 95

The main regulations are contained in CPUC General Order 95.
The entire rule set is available as a PDF here.

Below is Table 1 (page III-23) from General Order 95 – click the image to enlarge to a downloadable pdf. These CPUC Tables are complex and take time to understand. The point here is that no circuit operating at less than 60,000 volts must have a vegetation clearance of more than 48 inches. At 60,000 volts clearance rises to 6 feet.

Below is some excerpted text from Table 1 (and accompanying footnotes) to draw to your attention. Text in blue italics are comments from us.

Case No.E Supply Conductors and Supply Cables, 750-22,500 VoltsF Supply Conductors and Supply Cables 22.5-300kV
13. Radial clearance of bare line conductors from tree branches or foliage (aaa) (ddd)18 inches (bbb)1/4 pin spacing show in Table 2 Case 15 (bbb) (ccc)
Not a vegetation clearance prescription.
14. Radial clearance of bare line conductors from vegetation in the Fire-Threat District (aaa) (ddd) (hhh) (jjj)48 inches (bbb) (iii)48 inches (fff) (60kV or less)

(aaa) Special requirements for communication and supply circuits energized at 0-750 volts (see Rule 35) Note: clearance is less at 750 volts or less.

(bbb) May be reduced for conductor of less than 60,000 volts when protected from abrasion and grounding by contact with tree  (see Rule 35)      

(ddd) Clearances in this case shall be maintained for normal annual weather variations, rather than at 60 degrees, no wind.

(fff) Clearances in this case shall be increased for conductors operating above 72 kV, to the following:
1. Conductors operating between 72kV and a 110 kV shall maintain a 72 inch clearance
2. Conductors operating above 110 kV shall maintain a 120 inch clearance.  
Note: 72,000 or 72kV volts is transmission, true high voltage, and is not found connected to houses.

(hhh) The High Fire-Threat District is defined in GO 95, Rule 21.2-D.

(iii) May be reduced to 18 inches for conductors operating less than 2.4 kV.

Excerpt from General Order 95 – Rule 35 (page III-19)

35 Vegetation Management

Guidelines to Rule 35 (Appendix E)


[Interpretation of this distinction is a legal question that the authors of this website do not claim qualification to address. You will have to draw your own conclusions or consult a qualified attorney.  However it is striking that these two sections are in direct contradiction with each other.] 

Our understanding is that a “Guideline” is not an administrative law regulation.  For example if the Commission had concluded that 12 feet of clearance was necessary in High Fire Threat Districts, the Commission could have changed Table 1. They did not.  In December of 2017 and January of 2018, the Commission issued a “Record of Decision” adopting a utility ignition wildfire threat map for all of California.  This map defines what are High Fire Threat Districts or HFTD.

This is also when this “Guideline” was added to Rule 35, the Commission claimed that this change in General Order 95 would have no significant impact on the environment and that it was exempt from review under the CA Environmental Quality Act or CEQA.  In 2018 PG&E started EVM with the massive destruction of trees along its powerlines.

CalFire’s additional vegetation clearance rules, separate from those of the CPUC

We think these regulations apply to lands where CalFire has a responsibility for firefighting and the land is forest, brush or grass covered.

Public Resources Code – PRC

CHAPTER 3. Mountainous, Forest-, Brush- and Grass-Covered Lands [4291 – 4299]   ( Chapter 3 added by Stats. 1965, Ch. 1144. )

PRC §4292  Except as otherwise provided in Section 4296, any person that owns, controls, operates, or maintains any electrical transmission or distribution line upon any mountainous land, or forest-covered land, brush-covered land, or grass-covered land shall, during such times and in such areas as are determined to be necessary by the director or the agency which has primary responsibility for fire protection of such areas, maintain around and adjacent to any pole or tower which supports a switch, fuse, transformer, lightning arrester, line junction, or dead end or corner pole, a firebreak which consists of a clearing of not less than 10 feet in each direction from the outer circumference of such pole or tower. This section does not, however, apply to any line which is used exclusively as telephone, telegraph, telephone or telegraph messenger call, fire or alarm line, or other line which is classed as a communication circuit by the Public Utilities Commission. The director or the agency which has primary fire protection responsibility for the protection of such areas may permit exceptions from the requirements of this section which are based upon the specific circumstances involved.

PRC §4293  Except as otherwise provided in Sections 4294 to 4296, inclusive, any person that owns, controls, operates, or maintains any electrical transmission or distribution line upon any mountainous land, or in forest-covered land, brush-covered land, or grass-covered land shall, during such times and in such areas as are determined to be necessary by the director or the agency which has primary responsibility for the fire protection of such areas, maintain a clearance of the respective distances which are specified in this section in all directions between all vegetation and all conductors which are carrying electric current:
(a) For any line which is operating at 2,400 or more volts, but less than 72,000 volts, four feet.
(b) For any line which is operating at 72,000 or more volts, but less than 110,000 volts, six feet.
(c) For any line which is operating at 110,000 or more volts, 10 feet.
In every case, such distance shall be sufficiently great to furnish the required clearance at any position of the wire, or conductor when the adjacent air temperature is 120 degrees Fahrenheit, or less. Dead trees, old decadent or rotten trees, trees weakened by decay or disease and trees or portions thereof that are leaning toward the line which may contact the line from the side or may fall on the line shall be felled, cut, or trimmed so as to remove such hazard. The director or the agency which has primary responsibility for the fire protection of such areas may permit exceptions from the requirements of this section which are based upon the specific circumstances involved.

PRC §4294  A clearing to obtain line clearance is not required if self-supporting aerial cable [spacer cable] is used. Forked trees, leaning trees, and any other growth which may fall across the line and break it shall, however, be removed. (Added by Stats. 1965, Ch. 1144.)

PRC §4295  A person is not required by Section 4292 or 4293 to maintain any clearing on any land if such person does not have the legal right to maintain such clearing, nor do such sections require any person to enter upon or to damage property which is owned by any other person without the consent of the owner of the property. (Added by Stats. 1965, Ch. 1144.)

PRC §4295.5
(a) Notwithstanding any other law, including Section 4295, a person who owns, controls, operates, or maintains an electrical transmission or distribution line may traverse land as necessary, regardless of land ownership or express permission to traverse land from the landowner, after providing notice and an opportunity to be heard to the landowner, to prune trees to maintain clearances pursuant to Section 4293, and to abate, by pruning or removal, any hazardous, dead, rotten, diseased, or structurally defective live trees. The clearances obtained when the pruning is performed shall be at the full discretion of the person that owns, controls, operates, or maintains any electrical transmission or distribution line, but shall be no less than what is required in Section 4293. This section shall apply to both high fire threat districts, as determined by the California Public Utilities Commission pursuant to its rulemaking authority, and to state responsibility areas.

(b) Subdivision (a) does not exempt a person who owns, controls, operates, or maintains an electrical transmission or distribution line from liability for damages for the removal of vegetation that is not covered by an easement granted to the person for the electrical transmission or distribution line. (Amended by Stats. 2021, Ch. 133, Sec. 69. (SB 272) Effective July 23, 2021.)

Click here for a downloadable copy of CPUC General Order 95