20 CSR 4240-23.030
Electrical Corporation Vegetation Man
agement Standards and Reporting Requirements
PURPOSE: This rule sets forth requirements that electrical corpo
rations shall follow in managing vegetation in proximity to an
energized distribution conductor and sets reporting requirements
for transmission line vegetation management in order to pro
mote a safe, efficient and reliable supply of electric power. The
requirements in this rule provide the minimum standards for
the vegetation management programs of electrical corporations.
Each electrical corporation must have a vegetation management
plan and keep appropriate records to ensure that timely vegeta
tion management is accomplished. These records must be made
available to the Missouri Public Service Commission (commission)
upon request.
PUBLISHER’S NOTE: The secretary of state has determined that the
publication of the entire text of the material which is incorporated
by reference as a portion of this rule would be unduly cumbersome
or expensive. This material as incorporated by reference in this
rule shall be maintained by the agency at its headquarters and
shall be made available to the public for inspection and copying
at no more than the actual cost of reproduction. This note applies
only to the reference material. The entire text of the rule is printed
here.
(1) Definitions. The following words and terms, when used in
this rule, shall have the following meaning unless the context
clearly indicates otherwise.
(A) Arboriculture means the cultivation of trees, shrubs and
other woody plants.
(B) Contractor means a person or entity, other than the
commission, with which electrical corporation contracts to
perform work, furnish information and/or material. This term
includes all subcontractors engaged by a contractor to perform
any of the obligations required by a contract.
(C) Distribution line means a primary electric voltage line,
wire or cable, energized at less than two hundred thousand
(200,000) volts. However, any distribution line subject to this
rule shall thereafter be exempt from this rule at such time
the electrical corporation provides the commission written
proof that such distribution line has been deemed “critical to
the reliability of the region” by the Federal Energy Regulatory
Commission (FERC), a regional reliability organization or the
North American Electric Reliability Council (NERC).
(D) Energized conductor means an electric circuit or equip
ment through which electricity is flowing or usually flows
within the transmission or distribution system.
(E) Electrical corporation means electrical corporation as
defined in section 386.020(15), RSMo Supp. 2007.
(F) Right-of-way means less than fee interest in property,
which gives a public utility a limited right to use land owned
by another person or entity for the purpose of transmitting or
distributing electricity. This right is typically memorialized in
an easement.
(G) Rural means those areas in which there are fewer than
thirty-five (35) customers per circuit mile.
(H) Transmission line means an electrical line, wire or cable
(including the supporting structures), and appurtenant facili
ties which transmits electricity from a generating plant to elec
tric distribution lines, and is operated at or above two hundred
thousand (200,000) volts.
(I) Tree means a woody plant at least twelve feet (12') tall at
maturity with one (1) main stem and having a distinct head in
most cases.
(J) Urban means those areas in which there are thirty-five (35)
or more customers per circuit mile.
(K) Vegetation means trees, shrubs and other woody plants.
(L) Vegetation management means the removal of vegeta
tion or the prevention of vegetative growth to maintain safe
conditions around energized conductor(s) and ensure reliable
electric service. Vegetation management consists of biological,
chemical, cultural, manual and mechanical methods to control
vegetation in order to prevent hazards caused by the encroach
ment of vegetation on energized conductor(s), and to provide
utility access to the conductor.
(M) Volts means nominal voltage levels, measured phase-tophase.
(N) Woody plant means any vascular plant that has a peren
nial woody stem and supports continued vegetative growth
above ground from year-to-year and includes trees.
(2) General Provisions.
(A) An electrical corporation shall ensure that vegetation
management is conducted in accordance with this rule along
energized distribution line conductors of six hundred (600)
volts and higher, that the electrical corporation owns, in whole
or in part.
(B) Each electrical corporation shall obtain for its own em
ployees, and shall contractually require that its contractors ob
tain, all required permits and licenses prior to commencement
of vegetation management.
(C) Each electrical corporation and its contractors using
chemical or biological agents in vegetation management shall
comply with any laws or regulations governing the use of those
biological and chemical agents.
(D) Each electrical corporation shall employ a vegetation
manager. The vegetation manager shall supervise all aspects of
the electrical corporation’s vegetation management program,
and shall ensure that the electrical corporation complies with
this rule. The vegetation manager’s name and contact informa
tion shall be posted on the electrical corporation’s website and
shall be included on all notifications provided pursuant to the
notice requirements of section (7) of this rule.
(E) Each electrical corporation and its contractors shall in
form workers hired to perform vegetation management of all
applicable federal, state, county, and municipal laws, rules or
regulations that apply to the work performed under this rule.
The electrical corporation shall also ensure that all contractors
comply with each applicable requirement of this rule.
(F) An electrical corporation that agrees to perform vegeta
tion management at the request of a municipality or govern
ment agency, other than vegetation management required
under this rule, may require the requesting party to pay any
cost above the electrical corporation’s cost to perform the
vegetation management required by this rule. An electrical
corporation shall not perform such additional vegetation
management if the additional vegetation management would
decrease the reliability or safety of an energized conductor.
AND INSURANCE
(G) Upon an electrical corporation’s receiving notice of, or
having actual knowledge of, vegetation conditions that pose
an imminent threat to the reliable or safe function of electrical
facilities, the electrical corporation shall promptly remove or
remedy the potential threat. If, pursuant to the first sentence
of this section, removal of the vegetation requires the electrical
corporation to access or cross property for which it does not
hold an easement or other legal authorization, the electrical
corporation shall make reasonable efforts to obtain any nec
essary permission from the property owner and remove or
remedy the potential safety concern as promptly as possible.
(3) Maintenance Cycle.
(A) An electrical corporation shall perform a visual inspec
tion at least once every two (2) years of all urban energized
distribution conductors and at least once every three (3) years
of all rural energized distribution conductors, to determine
whether vegetation management is needed. Where needed,
the electrical corporation shall perform vegetation manage
ment in a timely manner. Vegetation management performed
along a circuit in compliance with this rule shall meet this two
(2)- or three (3)-year visual inspection requirement, accordingly.
(B) In addition to the maintenance required in subsection
(3)(A) above, if an electrical corporation becomes aware either
through notification or during the inspections required under
subsection (3)(A) above or at any other time, of any vegetation
close enough to pose a threat to its energized conductor, which
is likely to affect reliability or safety prior to the next required
vegetation management, the electrical corporation shall en
sure that necessary vegetation management is promptly per
formed as required under section (4) of this rule.
(4) Technical Standards for Vegetation Management.
(A) Each electrical corporation shall ensure that vegetation
management conducted on its energized distribution conduc
tors is performed in accordance with the following applicable
standards, which are hereby incorporated by reference, include
no later amendments or additions, are on file with the commis
sion’s data center and available for inspection:
1. “Pruning, Trimming, Repairing, Maintaining, and
Removing Trees, and Cutting Brush—Safety Requirements,
2006.” This document, also known as ANSI Z133.1-2006, is pub
lished by the American National Standards Institute, 1819 L
Street, N.W., Suite 600, Washington, DC 20036;
2. Part 1 of the document entitled “Tree, Shrub, and Other
Woody Plant Maintenance—Standard Practices, 2001.” This
document, also known as ANSI A300-2001, is published by the
American National Standards Institute, 1819 L Street, N.W., Suite
600, Washington, DC 20036; and
(B) Each electrical corporation shall develop its own veg
etation management standards, guidelines and procedures,
which shall be consistent with this rule. In developing these
standards, guidelines and procedures, an electrical corporation
shall prioritize its vegetation management based upon:
1. The extent of the potential for vegetation to interfere
with the energized conductor;
2. The voltage of the affected energized conductor; and
3. The relative importance of the affected energized con
ductor in maintaining safety and reliability.
(C) Each electrical corporation shall file a copy of its vege
tation management standards, guidelines and procedures at
the commission by July 1, 2008, with verification by affidavit
of an officer who has knowledge of the matters stated therein.
If an electrical corporation makes a change in its vegetation
management standards, guidelines or procedures, it shall file
a copy of the change at the commission no later than thirty
(30) days prior to implementing the change, with verification
by affidavit of an officer who has knowledge of the matters
stated therein.
(D) Each electrical corporation’s vegetation management
standards, guidelines and procedures shall cover, at a mini
mum, all of the following activities:
1. Tree pruning and removal;
2. Vegetation management around poles, substations and
energized conductors;
3. Manual, mechanical, biological or chemical vegetation
management along rights-of-way;
4. Inspection of areas where vegetation management is
performed, both before and after the vegetation management;
5. Research and development of improved vegetation
management; and
6. Public education.
(E) Among the factors the electrical corporation shall con
sider in determining the extent of vegetation management to
be performed at a particular site are:
1. The rate at which each species of vegetation is likely to
grow back;
2. The voltage of the energized conductor, with higher
voltages requiring larger clearances;
3. Sag of conductors at elevated temperatures and under
wind and ice loading, and growth habit, strength, and health
of vegetation growing adjacent to the conductor with the
combined displacement of the vegetation, supporting struc
tures, and conductors under adverse weather or routine wind
conditions; and
4. The electrical corporation’s legal rights to access the
area where vegetation management is to be performed.
(F) The electrical corporation shall remove all trimmings and
cut vegetation resulting from vegetation management that
are part of the electrical corporation’s regular maintenance
cycle, within five (5) business days after the vegetation was
cut, except if:
1. The electrical corporation obtains consent from the
owner of the property upon which the trimmings or cut vege
tation are located to leave the trimmings or cut vegetation; or
2. The vegetation management is performed as a direct
result of an outage caused by a storm as described in the elec
trical corporation’s standard procedures. The electrical corpo
ration shall include a copy of its standard procedures regard
ing removal of trimmings or cut vegetation during outages
caused by a storm in its annual vegetation management filing.
If the electrical corporation proposes to change its standard
procedures regarding removal of trimmings or cut vegetation
during outages caused by a storm, the electrical corporation
shall file the proposed changes with the commission, and other
parties shall have thirty (30) days to comment on the proposed
changes.
(5) Transmission Line Vegetation Management. Every electrical
corporation shall send the commission’s energy department a
copy of every filing it makes on vegetation management of its
transmission lines with the FERC, a regional reliability organi
zation, or the NERC.
(6) Training, Record Keeping and Reporting.
(A) Each electrical corporation shall adopt standards to be
used by all persons who perform vegetation management for
the electrical corporation, whether employees or contractors,
for the proper care of trees and other woody plants, including
safety practices and line clearance techniques.
(B) The electrical corporation shall monitor and document
all scheduled vegetation management and related activities it
or its contractors performs. Documentation shall include, but
shall not be limited to:
1. Identification of each circuit and substation where veg
etation management was performed;
2. The type of vegetation management performed includ
ing removal, trimming and spraying and methods used;
3. The crew size and supervisor’s name;
4. The date of activity;
5. Any safety hazards encountered; and
6. Any unexpected occurrence or accident resulting in
death, life-threatening or serious injury to a person assigned to
perform vegetation management activities or the public;
(C) Each electrical corporation shall include a summary of
the information required in subsection (6)(B) above about its
vegetation management during the past year, and vegetation
management planned for the following year in an annual re
port to be filed with the commission by April 1 each year, with
verification by affidavit of an officer who has knowledge of the
matters stated therein. The report shall also include:
1. Expenditures for vegetation management in the preced
ing year;
2. Vegetation management budget for the current year;
3. Circuits, completion dates and miles trimmed in the
preceding year;
4. Circuits, completion dates and miles scheduled for the
current year; and
5. Total distribution miles for the system and correspond
ing classification between rural and urban.
(D) Each electrical corporation shall report its own violations
of this rule to the commission within thirty (30) days of discov
ery and include its plan for correcting the violation.
(E) The staff of the commission shall review each electrical
corporation’s vegetation management annual report for com
pliance with the provisions of this rule. The staff shall identify
any deficiencies in the annual report of each electrical corpo
ration and file its analysis and recommendations for each elec
trical corporation complying with the provisions of this rule.
(7) Public Notice of Planned Vegetation Management.
(A) Each electrical corporation shall make a diligent attempt
to notify all property owners or occupants that may be affected
by planned vegetation management. This requirement will be
satisfied if the electrical corporation provides notice to affected
property owners or occupants at least seven (7) days, but not
more than ninety (90) days, prior to performing planned vege
tation management activity. Notice shall be provided by direct
mailing, door hanger, postcard, bill insert, personal contact or
any other commission-approved method.
(B) Each electrical corporation shall maintain a record of the
dates, content, and addresses to which all notices provided
under subsection (7)(A) were given until the subsequent vege
tation management cycle has occurred for each affected prop
erty owner or occupant.
(C) Each electrical corporation or its contractor shall provide
written notice of any pending vegetation management activ
ities to a primary contact for each county and municipality
affected. The primary contact shall be selected by mutual
agreement between the electrical corporation and the highest
elected official, or if no elected official, then the highest ap
pointed official, of the county and municipality.
(D) An electrical corporation shall notify counties and mu
nicipalities that may be affected by vegetation management
activities. The notice shall be made in writing to the primary
contact designated under subsection (7)(C) above, at least two
(2) months in advance of the planned vegetation management.
This notice shall include the planned dates and locations of the
vegetation management. In addition, the notice of vegetation
management shall be in a form appropriate to each electrical
corporation’s procedures and easement rights.
(8) Outreach Programs.
(A) Each electrical corporation shall conduct an annual
public education program to inform its customers, as well as
the political subdivisions in the electrical corporation’s service
territory, of the importance of vegetation management, and of
the electrical corporation’s role and responsibility in managing
vegetation near electric lines.
(B) The public education program required under this sec
tion shall be implemented by direct mail or another method
approved by the commission.
(C) Each electrical corporation shall post its public education
materials on its website.
(9) Specific Requirements.
(A) Each electrical corporation shall perform vegetation
management in accordance with this rule as follows:
1. On no less than fifteen percent (15%) of its total urban
distribution miles by the twelve (12) month anniversary of the
effective date of this rule, and on no less than fifteen percent
(15%) of its total rural distribution miles by the eighteen (18)
month anniversary of the effective date of this rule;
2. On no less than forty percent (40%) of its total urban
distribution miles by the twenty-four (24) month anniversary of
the effective date of this rule, and on no less than forty percent
(40%) of its total rural distribution miles by the thirty-six (36)
month anniversary of the effective date of this rule;
3. On no less than seventy percent (70%) of its total urban
distribution miles by the thirty-six (36) month anniversary of
the effective date of this rule, and on no less than seventy per
cent (70%) of its total rural distribution miles by the fifty-four
(54) month anniversary of the effective date of this rule;
4. On no less than one hundred percent (100%) of its total
urban distribution miles by the four (4) year anniversary of the
effective date of this rule, and on no less than one hundred
percent (100%) of its total rural distribution miles by the six (6)
year anniversary of the effective date of this rule; and
5. Thereafter, on no less than twenty-five percent (25%) of
its total urban distribution miles each year, and on no less than
twenty-five percent (25%) of its total rural distribution miles
each eighteen (18) months.
(B) To the extent permitted by current easements or other
authority, each electrical corporation must maintain the fol
lowing minimum clearances of vegetation from conductors at
the time vegetation management is conducted:
1. For conductors energized above fifty thousand (50,000)
volts, fifteen feet (15') or the edge of the right of way, whichever
is less;
2. For conductors energized at six hundred (600) through
fifty thousand (50,000) volts, ten feet (10') or the edge of the
right of way, whichever is less;
3. Subtransmission lines and three (3)-phase distribution
feeders/backbone circuits (portion of distribution system di
rectly interconnected with distribution substation and prior
to the first protective device) shall be trimmed vertically to
remove overhanging limbs to the widths prescribed in para
graphs (9)(B)1. and (9)(B)2. above;
4. Notwithstanding any provision to the contrary in this
section (9), for conductors energized at or below thirty-five
AND INSURANCE
thousand (35,000) volts, mature trees whose trunks or limbs
have sufficient strength and rigidity to prevent the trunk or
limbs from damaging the conductor under reasonably foresee
able wind and weather conditions are exempt from the mini
mum clearance requirements in this section (9); and
5. The radial clearances in subsection (9)(B) are minimum
clearances that should be established between the vegetation
and the energized conductors and associated live parts where
practicable. Vegetation management practices may make it
advantageous to obtain greater clearances than those listed. In
the event that the specific trimming conflicts with any other
materials within this chapter the strictest rules shall apply.
(10) In the event an electrical corporation incurs expenses as
a result of this rule in excess of the costs included in current
rates, the corporation may submit a request to the commis
sion for accounting authorization to defer recognition and
possible recovery of these excess expenses until the effective
date of rates resulting from its next general rate case, filed
after the effective date of this rule, using a tracking mecha
nism to record the difference between the actually incurred
expenses as a result of this rule and the amount included in
the corporation’s rates, or if there is no identifiable amount
included in the corporation’s rates, the amount reflected in the
appropriate uniform system of accounts account for vegetation
management on the corporation’s books for the test year (as
updated) from the corporation’s last rate case will be used to
determine the amount included in current rates. In the event
that such authorization is granted, the next general rate case
must be filed no later than five (5) years after the effective date
of this rule. Parties to any electrical corporation request for
accounting authorization pursuant to this rule may ask the
commission to require the electrical corporation to collect and
maintain data (such as actual revenues and actual vegetation
management expenses) until such time as the commission
addresses ratemaking for the deferrals. The commission will
address the ratemaking of any costs deferred under these ac
counting authorizations at the time the electrical corporation
seeks ratemaking in a general rate case.
(11) Variances. A variance from a provision of this rule may be
granted only for good cause shown. Nothing in this rule shall
prevent an electrical corporation from proposing and the com
mission from approving an alternative vegetation manage
ment plan in variance of paragraphs (9)(B)1. and 2., if the elec
trical corporation can establish that the alternative vegetation
management plan has previously produced greater reliability
performance than would be produced under this rule or that
the alternative vegetation management plan shall produce
greater reliability performance in the future than would be
produced under this rule.
AUTHORITY: sections 386.040, 386.250, 386.310 and 393.140,
RSMo 2000 and section 393.130, RSMo Supp. 2007.* This rule orig
inally filed as 4 CSR 240-23.030. Original rule filed Dec. 14, 2007,
effective June 30, 2008. Moved to 20 CSR 4240-23.030, effective
Aug. 28, 2019.
*Original authority: 386.040, RSMo 1939; 386.250, RSMo 1939, amended 1963, 1967,
1977, 1980, 1987, 1988, 1991, 1993, 1995, 1996; 386.310, RSMo 1939, amended 1979,
1989, 1996; 393.130, RSMo 1939, amended 1949, 1967, 1969, 2002; and 393.140, RSMo
1939, amended 1949, 1967.