ELECTRICAL HAZARDS

4.1 General

4.1.1

All applicable requirements in Section 3, General Safety Requirements, shall apply to this section.

4.1.2

The employer shall train each employee that all overhead and underground electrical conductors, guy wires, pole grounds, and communication wires and cables shall be considered energized with potentially fatal voltages.

4.1.3

Arborists’ training and degree of training in electrical hazards shall be determined by the risk to the employee for hazard(s) involved.

4.1.4

All arborists and other workers shall be instructed that:

  1. the human body is conductive and poses little resistance to electric current and will provide a path for the flow of electricity to a grounded object or to the ground itself;
  2. direct contact or indirect contact (phase-to-ground contact) with an electrical conductor, energized tree limb, tool, or equipment, or other energized object may lead to electric shock, significant injury, or death;
  3. the woody parts of trees, leaves, branches, needles, palm fronds, etc., are conductive;
  4. simultaneous contact with two separate energized conductors (phase-to-phase contact) will cause electric shock that may result in serious or fatal injury;
  5. electrical shock may occur as a result of ground fault when a person stands near a grounded object that becomes energized (e.g., an uninsulated part of an aerial device comes into contact with a conductor); and
  6. in the event of a downed energized electrical conductor or energized grounded object (e.g., guy wires or pole grounds), there exists the hazard of touch and step potential.

4.1.5

An inspection shall be made by a qualified arborist to determine whether an electrical hazard exists before climbing, otherwise entering, or performing work in or on a tree.

4.1.6

When determining the presence of an electrical hazard, consideration shall be given to the potential movement of an electrical supply line due to wind, load sag, or other factors that affect the line’s position in relation to the work.

Tab1

4.1.7

Arborists not qualified by training and experience to work within 10 feet (3.05 m) of electrical conductors shall maintain at all times the minimum approach distances (MAD) shown in Table 1, measured radially.

4.1.8

Arborists should climb on the side of the tree that is away from energized electrical conductors.

4.1.9

Climbers’ body, gear, and their conductive equipment shall be maintained at the required minimum approach distance (MAD) or greater, shown in Tables 1, 2, or 3, as applicable.

4.1.10

The climber’s tie-in point should be above the climber’s work position and located in such a way that a slip would swing the arborist away from any energized electrical conductor or other identified hazard.

4.1.11

A conductive rope may not be used within the minimum approach distances (MAD) shown in Tables 1, 2, or 3, as applicable.

4.1.12

Portable ladders shall not have conductive side rails if they are used where the employee or the ladder could contact exposed energized parts.

4.1.13

Ladders, platforms, and aerial devices, including insulated aerial devices, shall be subject to minimum approach distances in accordance with Tables 1, 2, or 3, as applicable.

4.1.14

Due to the hazards of step and touch potential, if the distance between the aerial device and energized conductor(s) is unintentionally less than the required minimum approach distance (MAD), workers on the ground shall move away and remain clear of the aerial-device vehicle and attached equipment (e.g., chipper) until the required MAD is re-established.

4.1.15

Emergency response to an electric contact shall be performed in accordance with Section 3.2, Emergency Procedures and Readiness.

4.1.16

Arboricultural operations in proximity to energized electrical conductors shall not be performed during adverse weather conditions, such as thunderstorms, high winds, snow storms, or ice storms.

4.2 Working in Proximity to Electrical Hazards – Incidental Line Clearance (29 CFR 1910, Subpart S)

4.2.1

The items contained in Section 4.1, General, shall always be included in the review of this section.

4.2.2

Workers shall be trained on safety-related work practices that protect employees against the voltage level to which they are exposed.

4.2.3

Safety-related work practices shall be employed to prevent electric shock or other injuries resulting from either direct or indirect electrical contacts and shall be consistent with the nature and extent of the electrical hazards present.

4.2.4

Training for qualification of qualified incidental line clearance arborists requires a minimum of:

  1. the skills and techniques necessary to distinguish exposed live parts from other parts of electric equipment;
  2. the skills and techniques necessary to determine the nominal voltage of exposed live parts; and
  3. the minimum approach distances (MAD) specified in Table 2 and the corresponding voltages to which the qualified person will be exposed.
Tab2

4.2.5

Before work is performed within the minimum approach distance (MAD) without insulated tools, overhead energized lines shall be de-energized. It shall be the responsibility of the system owner/operator of the electrical system to make the system safe.

4.2.6

When a qualified incidental line-clearance arborist is working in the vicinity of overhead lines, whether in an elevated position or on the ground, the person shall not approach or take any conductive object closer to exposed energized parts than shown in Table 2.

4.2.7

Branches and other parts of trees within the minimum approach distances (MAD) which have been browned or charred by past electrical arcing or contact should be considered likely to become re-energized without warning and thus should be treated as energized. Climbing of trees in such condition should be avoided.

4.2.8

Tools that are not rated as insulated for the voltage to which they are exposed shall be considered conductive.

4.3 Working in Proximity to Electrical Hazards – Utility Line Clearance (29 CFR 1910.269)

4.3.1

The items contained in Section 4.1, General, shall always be included in the review of this section.

4.3.2

The employer shall verify that each line-clearance arborist is qualified to work within proximity to electrical hazards that the arborist is exposed to and has been trained in the following topics:

  1. To be familiar with safety-related work practices, procedures, and other requirements that pertain to his or her job assignments.
  2. On emergency and work-related rescue procedures that are related to his or her work and are necessary for the safety of the worker.

4.3.3

Qualified line-clearance arborists shall also be trained and competent in:

  1. The skills and techniques necessary to distinguish exposed, energized parts from other parts of electric equipment.
  2. The skills and techniques necessary to determine the nominal voltage of exposed energized parts.
  3. The MAD specified in Table 3 and the corresponding voltages to which the qualified line-clearance arborist will be exposed and the skills and techniques necessary to maintain those distances, for the nominal voltage present.
Tab3

4.3.4

The employer shall ensure that each employee has demonstrated proficiency in the work practices involved before that employee is considered as having completed the training.

4.3.5

When qualified line-clearance arborist trainees are assigned to work where an electrical hazard exists, the qualified line-clearance arborist trainees shall be under the direct supervision of qualified line-clearance arborists.

4.3.6

Qualified line-clearance arborists and qualified line-clearance arborist trainees performing line clearance after a storm or under similar conditions shall be trained in the hazards associated with this type of work and in the recognition of the hazards of step potential.

4.3.7

Line-clearance operations shall be suspended when adverse weather conditions or emergency conditions develop involving energized electrical conductors. Electrical system owners/operators shall be notified immediately.

4.3.8

When performing line-clearance work for the electrical system owner/operator (host employer) – it shall be the responsibility of the contract employer receiving host utility information to communicate it and any hazardous conditions relevant to the affected workers performing the affected work.

  1. Before work begins, the contract employer and the host employer shall coordinate their work rules and procedures so that each employee of the contract employer and the host employer is protected.
  2. Before work begins, the contract employer shall advise the host employer of any unique hazardous conditions presented by the contract employer’s work.
  3. The contract employer shall advise the host utility/employer of any unanticipated hazardous conditions of the electrical system found during the contract employer’s work. This information shall be provided to the host utility within two working days after discovering the hazardous condition.

4.3.9

A second qualified line-clearance arborist or line-clearance arborist trainee (with a minimum of training in emergency procedures), shall be within unassisted voice communication and should be within visual contact during line-clearance operations aloft when a qualified line-clearance arborist or line-clearance arborist trainee must approach closer than 10 feet (3.05 m) to any energized electrical conductor in excess of 750 volts (primary conductor) or when:

  1. branches or limbs are being removed, which cannot first be cut (with an insulated pole pruner/pole saw) to sufficiently clear electrical conductors, so as to avoid contact; and/or
  2. roping is required to remove branches or limbs from such electrical conductors.

4.3.10

Insulating pruning tools shall be designed and constructed to withstand the minimum testing, as outlined in Annex J, Live-Line Tools.

4.3.11

Qualified line-clearance arborists and line-clearance arborist trainees shall maintain minimum approach distances from energized electrical conductors in accordance with Table 3.

4.3.12

If the minimum approach distance (shown in Table 3) cannot be maintained during the arboricultural operations, the qualified line-clearance arborist shall request that the electrical system owner/operator’s designated supervisor in charge coordinate communications and operations between the electrical system owner/operator and the qualified line-clearance arborist to mitigate the electrical hazard. Mitigation options should include all safe, OSHA-compliant, and practical work methods, and, where necessary, de-energizing, testing, isolating, and grounding the electrical conductors by the electrical system owner/operator (see Annex H, Electrical Hazard Abatement). The designated electrical system owner/operator employee and the designated qualified line-clearance arborist in charge shall confirm that protective ground(s) have been installed as close as is practical to the line-clearance work to be performed to prevent hazardous differences in electrical potential.

4.3.13

Branches that are contacting exposed energized conductors or equipment, or that are within the distances specified in Table 3, may be removed only through the use of insulating equipment and/or tools.

4.3.14

Branches and other parts of trees within the minimum approach distances (MAD) which have been browned or charred by past electrical arcing or contact, should be treated with caution. The following steps should be followed when this condition is present:

  1. Climbing of trees in such condition should be assessed by a qualified line-clearance arborist and supervisor to determine whether or not an electrical hazard exists and mitigation is necessary before performing arboricultural operations.
  2. The arborist in charge shall establish a plan to safely manage the work.
  3. Work strategies, in accordance with contract employer and host utility work rules, shall be employed so that each employee of the contract employer and the host employer is protected (see Subsection 4.3.12 and Annex H, Electrical Hazard Abatement, on determining an electric hazard mitigation plan).

4.3.15

Rubber gloves, with or without leather or other protective covering, shall not be considered as providing any measure of safety from electrical hazards.

4.3.16

Footwear, including lineman’s overshoes or those with electrical-resistant soles, shall not be considered as providing any measure of safety from electrical hazards.