2017 Revisions to Part 4 (Work Rules)

NESC WORKSHOP

Sam Stonerock

October 18, 2016

Work Rules for the Operation of Electric Supply and Communications Lines and Equipment

2017 edition– Reconcile existing rules with FED-OSHA revisions

• Rule 410.3 on electric arc exposures / protection- New information addressing hand, head, feet protection

- New information for dc systems

- New information on 480V arc-in-a-box test results

• Rule 420K on fall protection- Fall protection to be used at elevated locations above 4 ft. - Appropriate equipment to limit free fall to 2 ft.

- Anchorages must support 3000 lb-force

- Employees to visually assess anchorages

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Work Rules for the Operation of Electric Supply and Communications Lines and Equipment

2017 edition (continued)• Minimum Approach Distances (MAD)

- Revise Table 431-1 (Communication)

- Revise Rule 441

- Adds rule specific definition for “reach”/”extended reach”

- Revise rules for voltages above 72.5kV

- Revise default Table 441-1 (Supply)

- Add new Tables 441-2, 441-3, 441-4 (‘T’ has been calc’d)

- Retain/renumber existing Tables 441-2, 441-3, 441-4

• Minimum clearances for open air gap - New Table 444-1 for supply stations and OH lines

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New / Revised Exceptions – EXCEPTION 2: Arc-rated equipment is not necessary for the

employee’s hands when the employee is wearing rubber

insulating gloves with protectors. Heavy-duty leather work

gloves with a weight of at least 407 gm/m2 (12 oz/yd2) may

be worn if the estimated incident energy is no more than 14

cal/cm2.

– EXCEPTION 3: Arc-rated equipment is not necessary for the

employee’s feet when the employee is wearing heavy-duty

work shoes or boots.

Rule 410A3

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New / Revised Exceptions EXCEPTION 4: Arc-rated equipment is not necessary for the employee’s head or face when the employee is wearing head protection meeting 29 CFR 1910.135 if the estimated incident

energy is less than OSHA 9 cal/cm2 for exposures involving single phase arcs in open air less

than or 5 cal/cm2 for other exposures. Arc-rated equipment is necessary for the protection of

the employee’s head and face and may consist of head protection meeting OSHA 29 CFR

1910.135 and a face shield with a minimum arc rating of 8 cal/cm2 if the estimated incident-energy exposure is greater than 9 cal/cm2 and less than 13 cal/cm2 for exposures involving

single-phase arcs in open air or greater than 5 cal/cm2 and less than 13 cal/cm2 for

exposures involving single-phase arcs in open air or greater than 5 cal/cm2 and less than 9

cal/cm2 for other exposures. For exposures involving single phase arcs in open air, the arc

rating for the employee’s head and face protection may be 4 cal/cm2 less than the estimated incident energy.

Rule 410A3

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Antennas410A6

The employer shall provide training to all employees who work in the vicinity of antennas

operating in the range of 3 kHz to 300 GHz to recognize and mitigate exposure to

radiofrequency sources that exceed exposure levels set forth by the regulatory authority having

jurisdiction. NOTE: See OSHA 29 CFR 1910.97, Subpart G [B67]; OSHA 29 CFR 1910.268, Subpart R [B68]; FCC Bulletin No.

65 [B32]; IEEE Std C95.1-2005 [B61].

420Q

Employees working in the vicinity of antennas operating in the range of 3 kHz to 300 GHz shall

use controls to mitigate exposure to radio-frequency sources that exceeds permissible exposure

levels.NOTE: See Rule 410A6.

New Rule 410A6 / Revised Rule 420Q

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1. Employees shall use appropriate fall protection equipment while climbing,

transferring, or transitioning across obstacles on poles or structures, unless doing so

not feasible or creates a greater hazard than doing so unattached.

a. When work positioning is used, it shall be rigged in a manner in which the

employee cannot free fall more than 0.60 m (2 ft).

b. Anchorages for work-positioning equipment shall be capable of supporting at least

twice the potential impact load of an employee’s fall, or 13.3 kN (3000 lb-force),

whichever is greater.

Rule 420K (Fall Protection)

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NOTE 1: Wood-pole fall-restriction devices meeting American Society of Testing and Materials Standard

Specifications for Personal Climbing Equipment, ASTM F887-04 [Bx] or later versions, are deemed to meet the anchorage-strength requirement when they are used in accordance with manufacturers’ instructions.

NOTE 2: Recognized and generally accepted good engineering practices, with consideration given to such

factors as design specifications and maintenance procedures, may be used in determining whether potential

anchorages meet the strength requirements in 420K1b provided the employee performs a visual inspection

before use that reveals nothing about the appearance of the anchorage (for example, corrosion around

support-member connections or bent support members) suggests that the applicable strength criteria would

not be met.

NOTE 3: On poles, when the employee is transitioning or at the work location and the work positioning strap

is positioned above a bolted attachment, step bolt, or other equipment, these attachments may serve as the

anchorage. It is not necessary to determine the strength of the attachment provided the employee performs a visual inspection before use that reveals nothing about the appearance of the anchorage (for example,

corrosion or cracks) suggests that the applicable strength criteria would not be met.

Rule 420K (continued)

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Rule 431 / Table 431-1

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441A1aA. Minimum approach distance to energized lines or parts1. General

Employees shall not approach or bring any conductive object within the minimum approach

distance listed in Table 441-1 or Table 441-5 or distances as determined by an engineering

analysis to exposed energized lines or parts unless one of the following is met:

a. The line or part is de-energized and grounded per Rule 444D.EXCEPTION: For voltages less than 600 V where the making of the ground is impractical, the

line or part may be isolated in lieu of installing temporary protective grounds provided the

following conditions are met: (a) the lines and equipment are isolated from all sources and

tested to be de-energized, (b) there is no possibility of contact with another energized source,

and (c) the hazard of induced voltage is not present.

Rule 441

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441A1d d. The employee is performing barehand live-line work according to Rule 446.NOTE 1: Minimum approach distances calculated under this rule for 0.301 kV to 0.750 kV contain

the electrical component plus 0.31 m (1 ft) for inadvertent movement. Voltages 0.751 kV to 72.5

kV contain the electrical component plus 0.61 m (2 ft) for inadvertent movement. Voltages above

72.5 kV contain the electrical component plus 0.31 m (1 ft) for inadvertent movement.

NOTE 2: Methodology for calculating minimum approach distances were taken from 29 CFR 1910.269 Appendix B [B66].

NOTE 3: The voltage ranges are contained in ANSI C84.1-1995, Table 1.

NOTE 4: For the purpose of Section 44, reach is defined as the range of anticipated motion of an

employee while performing a task, and extended reach is defined as the range of anticipated

motion of a conductive object being held by an employee while performing a task.

Rule 441

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441A4

When performing live line work, employees shall position themselves so that they are

not within the reach or extended reach of the applicable minimum approach distance.

In lieu of using the minimum approach distances in Table 441-1, the minimum

approach distance in Table 441-2 through Table 441-4 may be used provided the per

unit transient overvoltage value (T) has been determined through an engineering

analysis considering the system design, expected operating conditions, and control

measures.NOTE 1: Control measures include blocking reclosing, prohibiting switching during live line work, using protective air

gaps, use of closing resistors and surge arrestors, etc.

NOTE 2: IEEE Std 516-2009 [B37] and OSHA 29 CFR 1910.269 Appendix B [B66] contain information that may be

used to perform an engineering analysis to determine maximum transient overvoltage factors. The engineering

analysis may be performed on a system basis or a per-line basis.

Rule 441 (Tables)

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Rule 444 / New Table 444-1

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Subcommittee 8 Working Group(s) / 2022 Code Cycle

Working Group 8.14 – Part 4 – Generation FacilitiesWorking Group 8.14 was formed to address possible gaps in Part 4 rules regarding significance to work in

generating stations. The kick-off meeting for this WG was held in late August to perform a thorough review of

existing rules specifically to assess their relevance to that work. Additionally, a former member of Subcommittee

developed a draft Part 5, designed to specifically address work in generating stations. Also, the intent is to

deliver the WG’s new/revised draft rules to the full Subcommittee for consideration as new (SC8) Change

Proposal(s)

Working Group 8.XX – Part 4 / Part 1 – Storage batteries

Working Group 8.XX – Part 4 / Table 410-1

Working Group 8.XX – Part 4 / New Medium Voltage Arc Flash Table

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