1. National Electrical Safety Code 2017
SWEDE – Horseshoe Bay
2017

2. Accredited Standards Committee C2
NESC
Accredited Standards Committee C2
Secretariat – IEEE–SA
Main Committee
Executive Subcommittee
Interpretations Subcommittee
“Numbered” Subcommittees

3. Subcommittees
SC1: Sec 1-3 (Definitions, gen. rules, etc.) SC2: Section 9 – Grounding Methods SC3: Sections – Supply Stations SC4: Sections – OH Lines & Clearances SC5: Sections – Strength & Loading SC7: Sections – Underground Lines SC8: Sections – Work Rules

4. NESC Zone at http://standards.ieee.org
Change Proposals
SC1: 75 SC2: 39 SC3: 45 SC4: 300 SC5: 175 SC7: 68 SC8: 74
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Total 686
Comments
SC1: 84 SC2: 38 SC3: 52 SC4: 199 SC5: 262 SC7: 57 SC8: 54
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Total 634

5. National Electrical Safety Code
SC1 – General Rules
013. Application
B. Existing installations
3. Where conductors or equipment are added, altered, or replaced on an existing structure, the structure or the facilities on the structure need not be modified or replaced if the resulting installation will be in compliance with either (a) the rules that were in effect at the time of the original installation, or (b) the rules in effect in a subsequent edition to which the installation has been previously brought into compliance, or (c) the rules of this edition in accordance with Rule 13B1. When an existing installation is brought into compliance with a subsequent edition, earlier editions no longer apply.

6. National Electrical Safety Code
SC1 – General Rules
013. Application
B. Existing installations
3. For structures that currently do not comply with Rule B3, if adding a new item, or replacing or rearranging existing items would not in itself, either (1) create a structural, clearance, or grounding non-conformance, or (2) worsen an existing non-conformance, then the addition,
replacement, or alteration may be performed prior to correcting existing non-compliance items.
For existing non-compliance items, see Rules 214A4 and A (See IR 548)

7. National Electrical Safety Code SC2 - Grounding
Rule 092C – Message Wires and Guys
Exception added for 4 grounds in each mile in areas of extreme terrain
Messenger must be “sufficient size and ampacity”
Messenger must be grounded at all structures in that portion of the line

8. National Electrical Safety Code SC2 - Grounding
Rule 096C – Multi-grounded Systems
Exceptions to 4 grounds/mile rule allowed for inaccessible facilities and extreme terrain
Grounds required where personnel can access facilities

9. National Electrical Safety Code SC2 - Grounding
Rule 094B1
Stainless steel ground rods now included in non- ferrous metal category

10. National Electrical Safety Code SC2 - Grounding
Rule 094B2
Driven rods, buried wire, strips, and plates (>2 ft2) are considered to be equivalent.
Butt wraps and small plates are ½ electrodes.
There is a new Working Group to look at materials and dimensions of ground rods.

11. NESC 2017 Significant Changes SC3 - Electric Supply Stations
Rule 110A1 - No other fences may be located within 6 feet of the substation fence without concurrence of the substation owner.
Photo submitted with NESC CP 4572 by Allen Clapp

12. NESC 2017 Significant Changes SC3 - Electric Supply Stations
NESC Section 12 – Installation and Maintenance of Equipment
For Rules 110A and 124A, there is an altitude correction requirement for altitudes above 3300 feet for substation clearances. No specifics given but the following reference:
NOTE: For additional information, see IEEE Std C [Bx] and IEEE Std [Bx].

13. NESC 2017 Significant Changes SC3 - Electric Supply Stations
Fig Example of how to apply the safety clearance zone to an impenetrable fence per NESC Table and NESC Fig (Rule 110A2b).
Use R for gap
Figure from McGraw Hill’s NESC 2012 Handbook used with permission of Marne and Associates, Inc. and the McGraw-Hill Companies, Inc. © 2012

14. SC4 – OH Lines and Clearances
NESC
SC4 – OH Lines and Clearances
Guy Insulator
Energized lines
or parts area
A Performance Rule
Guy insulator shall be positioned such that no portion of the anchor guy, including any conductive components of the guy insulator, can become energized within 8 ft of the ground level when the anchor guy becomes slack or breaks below the lowest guy insulator
Anchor Guy
Provided by Mickey Gunter
Rule 215C4a
2012 Code

15. NESC SC4 – OH Lines and Clearances Guy Insulators
Rule 215C2a for 2017 NESC Requires Anchor Guys to be Effectively Grounded
Not a new Code requirement
The installation of guy insulators is an exception to the grounding rule
Exception 2 to Rule 215C2a:
Guy insulators shall be positioned so as to limit the likelihood of any portion of an anchor guy becoming energized within 2.45 m (8 ft) of the ground level in the event that the anchor guy becomes slack or breaks.

16. NESC SC4 – OH Lines and Clearances
Table 235-6

17. NESC SC4 - OH Lines and Clearances Table 235-6
Questions Surrounding Existing Table:
Application of “parallel to line”
Application of “anchor guys”
And what facilities are included in “all other”
SC4 Felt Table Needs to be Clarified
Discussions and received comments clearly indicate that the application of the existing table is not uniform.
Working Group Formed
Review the clearances between energized parts and down guys. Table Row 2a, b, and c.

18. NESC SC4 – OH Lines and Clearances Street Light Brackets
Revised Table to Require 40” Clearance Between an Ungrounded Street Light Bracket and Communication Facilities Within the Communication Space (CP4139).
Currently, 20” required
Not considered adequate if the street light bracket were to become energized
Clearance can be reduced to 4” if street light bracket grounded.

19. NESC SC4 – OH Lines and Clearances WGs Established
Working Groups Were Assigned to Provide SC4 Direction on Specific Change Proposals
WG 4.1 (CP 4683)
Determine if a new extreme ice loading criteria is required for road crossings
WG 4.2 (CP4468)
Determine if the Code needs to develop clearances to agricultural irrigation systems and water streams

20. NESC SC5 – Strength and Loading Re-format Rule 241.C. At Crossings
241. Application of grades of construction to different situations
2012 version
2017 version

21. NESC SC5 – Strength and Loading Re-format Rule 241.C. At Crossings
241. Application of grades of construction to different situations
2012 version
2017 version
Same Words
Easier to Comprehend

22. NESC SC5 – Strength and Loading Revise Table 242-1 Grades of Construction Applications
CP Intention:
Improve logical layout and format
Columns sequence from low to high voltage
Rows sequence from low to high voltage

23. 2012
Table 242-1

24. 2012
Table 242-1

25. 2017
Table 242-1

26. FN 3 reversed; higher grade in the table
NESC SC5 – Strength and Loading Revise Table Grades of Construction Applications
FN 3 reversed; higher grade in the table
3 Grade B C construction shall may be used if the supply circuits will not be promptly de-energized, both initially and following subsequent breaker operations, in the event of a contact with lower supply conductors or other grounded objects.

27. Add FN 11 – Grade N for dielectric fiber-optic supply cables
NESC SC5 – Strength and Loading Revise Table Grades of Construction Applications
Add FN 11 – Grade N for dielectric fiber-optic
supply cables
For communication, Grade N may be used for entirely dielectric fiber-optic supply cables meeting Rule 230F1b, insulated communication cables located in the supply space and supported by an effectively grounded messenger, and for communication cables supported on messengers that are bonded at intervals specified in Rule 092C to supply messengers supporting cable meeting Rule 230C1, 230C2, or 230C3. These grades of construction apply to communications service drops as well as cables.

28. Dielectric cables per Rule 230F1b
NESC SC5 – Strength and Loading Revise Table Grades of Construction Applications
Dielectric cables per Rule 230F1b
Insulated Comm Cables in Supply Space and supported by messenger that’s effectively grounded Or
messenger bonded at intervals specified in Rule 092C to Supply messengers supporting cable meeting Rule 230C
Add FN 11 – Grade N for dielectric fiber-optic
supply cables
For communication, Grade N may be used for entirely dielectric fiber-optic supply cables meeting Rule 230F1b, insulated communication cables located in the supply space and supported by an effectively grounded messenger, and for communication cables supported on messengers that are bonded at intervals specified in Rule 092C to supply messengers supporting cable meeting Rule 230C1, 230C2, or 230C3. These grades of construction apply to communications service drops as well as cables.

29. NESC SC5 – Strength and Loading Rule 250C, D Exemption - Tall Structures
Fuhgeht about it!!!!

30. NESC SC5 – Strength and Loading Clarify Rule 250D
…………
Add ice to:
Wires
Conductors
Cables
Messengers
Do not add ice to:
Structure
Other supported facilities

31. NESC SC5 – Strength and Loading Add Temperature Map to 250D
To Be Used
With 250D
Extreme Ice &
Concurrent Wind

32. NESC SC5 – Strength and Loading New ASCE Reference Extreme Wind Map
Minimum Design Loads for Buildings and Other Structures
ASCE 74-10
Guidelines for Electrical Transmission Line Structural Loading

33. NESC SC5 – Strength and Loading New ASCE Reference Extreme Ice Map
Minimum Design Loads for Buildings and Other Structures
2017 NESC
ASCE 7-10
Minimum Design Loads for Buildings and Other Structures

34. NESC SC5 Strength and Loading Aeolian Vibration – Rule 261H.1.b

35. NESC SC5 Strength and Loading Aeolian Vibration – Rule 261H.1.b

36. NESC SC5 – Strength and Loading Insulators – New Rating System
Old Line Post ratings:
Rating equal to average
Lowest no less than 85% of average
New Line Post ratings:
Rating = Minimum of all insulators

37. NESC SC5 – Strength and Loading Insulators – New Rating System
Old Transmission Suspension ratings:
1.2 standard deviations
New Transmission Suspension ratings:
3.0 standard deviations

38. NESC SC5 – Strength and Loading Insulators
CP Intention:
Introduce Load factors (LRFD)
Adjust allowable stresses
Mostly equivalent insulator applications
Introduce Classes: Distribution & Trans
Different allowables for Rule 250B vs 250C, D

39. NESC SC5 – Strength and Loading Insulators: Table 253-1 Load Factors

40. NESC SC5 – Strength and Loading Insulators: Table 253-1 Load Factors

41. NESC SC5 – Strength and Loading Insulators Table 277-1

42. NESC SC5 – Strength and Loading Insulators Table 277-1

43. NESC SC5 – Strength and Loading Insulators Table 277-1

44. NESC SC5 – Strength and Loading Insulators Table 277-1

45. NESC SC5 – Strength and Loading Nonceramic Table 277-1 cont’d

46. NESC SC5 – Strength and Loading Nonceramic Table 277-1 cont’d

47. NESC SC5 – Strength and Loading Nonceramic Table 277-1 cont’d

48. NESC SC5 – Strength and Loading Nonceramic Table 277-1 cont’d

49. NESC SC5 – Strength and Loading Nonceramic Table 277-1 cont’d
FN 3: This percentage shall be supplied by the manufacturer.

50. NESC SC5 – Strength and Loading Insulator Factory Tests Rule 274 Exception Added

51. NESC SC5 – Strength and Loading Insulator Factory Tests Rule 274 Exception Added
Where guy insulators manufactured per designs for which [1] validation tests have been performed, and
[2] a valid quality assurance program is followed,
this rule does not require that dry and wet flashover tests be performed on each guy insulator unit.

52. Random UG Separation (<12” apart)
NESC
SC7 – UG Lines
Random UG Separation (<12” apart)
D3a – Copper concentric neutral must have a conductance not less than one half that of the phase conductor.
This requirement practically eliminates the use of 3 phase cables in direct buried systems.
3-phase cables normally are 1/3 size neutrals
Studies show 1/3 is adequate for device tripping
Rule 354D3a was deleted.

53. NESC
SC7 – UG Lines
Grounding and Bonding
C. Bonding should be provided between all aboveground metallic supply and communications enclosures that are separated by a distance of 1.8 m (6 ft) or less. For the purpose of this rule, pole grounds are not required to be bonded to the communication enclosure.
The rule does not prohibit the practice of bonding between communication pedestals and supply pole grounds but, based on safety issues raised by studies, does not require it.
NOTE: This rule does not prohibit bonding communication metallic enclosures to supply pole grounds, provided all affected parties are in agreement.

54. NESC SC8 Work Rules for the Operation of Electric Supply and Communications Lines and Equipment
2017 edition
Reconcile existing rules with FED-OSHA revisions
Rule on arc hazard
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

55. SC8 Work Rules for the Operation of Electric Supply and Communications Lines and Equipment
2017 edition (continued)
Minimum Approach Distances (MAD)
Revise Table (Communication)
Revise Rule 441
Adds rule specific definition for “reach”/”extended reach”
Revise rules for voltages above 72.5kV
Revise default Table (Supply)
Add new Tables 441-2, 441-3, (‘T’ has been calc’d)
Retain/renumber existing Tables 441-2, 441-3, 441-4
Minimum clearances for open air gap
New Table for supply stations and OH lines

56. Rule 410A3 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.

57. Rule 410A3 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 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 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.

58. New Rule 410A6 / Revised Rule 420Q
Antennas
410A6
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 , Subpart G [B67]; OSHA 29 CFR , Subpart R [B68]; FCC Bulletin No. 65 [B32]; IEEE Std C [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.

59. Rule 420K – Fall Protection
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.

60. Rule 420K (continued)
NOTE 1: Wood-pole fall-restriction devices meeting American Society of Testing and Materials Standard Specifications for Personal Climbing Equipment, ASTM F [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.

61. Rule 431 / Table 431-1

62. Rule 441 New Exception
441A1a
A. Minimum approach distance to energized lines or parts
1. General
Employees shall not approach or bring any conductive object within the minimum approach distance listed in Table or Table 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.

63. Rule 441 Changed Notes
441A1d
d. The employee is performing barehand live-line work according to Rule 446.
NOTE 1: Minimum approach distances calculated under this rule for kV to kV contain the electrical component plus 0.31 m (1 ft) for inadvertent movement. Voltages kV to 72.5 kV contain the electrical component plus 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 Appendix B [B66].
NOTE 3: The voltage ranges are contained in ANSI C , 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.

64. Rule 441 / Tables
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 through Table 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 [B37] and OSHA 29 CFR 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.

65. Rule 444 / New Table 444-1

66. Subcommittee 8 Working Group(s)
Working Group 8.14 – Part 4 – Generation Facilities
Working 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. The next meeting of the working group was cancelled because of Hurricane Sandy and another meeting has not yet been scheduled
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)
Chair: J. Tomaseski; Members:
Working Group X.XX – Part 4 / Part 1 – Storage batteries

67. Questions?