2023 National Electrical Safety Code

✍ Scribed by IEEE

• Publisher: IEEE
• Year: 2023
• Tongue: English
• Leaves: 412
• Series: C2
• Category: Library

✦ Table of Contents

2023 National Electrical Safety Code® (NESC®) Front cover
Title page
Important Notices and Disclaimers Concerning the NESC®
Foreword
Committee Membership
Procedure for revising the NESC
Time schedule for the next revision of the NESC
Contents
Figures
Tables
Section 1. Introduction to the National Electrical Safety Code®
010. Purpose
011. Scope
012. General rules
013. Application
014. Waiver for emergency and temporary installations
015. Intent
016. Effective date
017. Units of measure
018. Method of calculation
Section 2. Definitions of special terms
Section 3. References
Section 9. Grounding methods for electric supply and communications facilities
090. Purpose
091. Scope
092. Point of connection of grounding conductor
093. Grounding conductor and means of connection
094. Grounding electrodes
095. Method of connection to electrode
096. Ground resistance requirements
097. Separation of grounding conductors
098. Number 098 not used in this edition.
099. Additional requirements for grounding and bonding of communication apparatus
Part 1. Safety Rules for the Installation and Maintenance of Electric Supply Stations and Equipment
Section 10. Purpose and scope of rules
100. Purpose
101. Scope
102. Application of rules
103. Referenced sections
Section 11. Protective arrangements in electric supply stations
110. General requirements
111. Illumination
112. Floors, floor openings, passageways, and stairs
113. Exits
Section 12. Installation and maintenance of equipment
120. General requirements
121. Inspections
122. Guarding shaft ends, pulleys, belts, and suddenly moving parts
123. Protective grounding
124. Guarding live parts
125. Working space about electric equipment
126. Equipment for work on energized parts
127. Classified locations
128. Identification
129. Mobile hydrogen equipment
Section 13. Rotating equipment
130. Speed control and stopping devices
131. Motor control
132. Number 132 not used in this edition.
133. Short-circuit protection
Section 14. Storage batteries
140. General
141. Switchgear and plant batteries
142. Grid storage batteries
Section 15. Transformers and regulators
150. Current-transformer secondary circuits protection when exceeding 600 V
151. Grounding secondary circuits of instrument transformers
152. Location and arrangement of power transformers and regulators
153. Short-circuit protection of power transformers
Section 16. Conductors
160. Application
161. Electrical protection
162. Mechanical protection and support
163. Isolation
164. Conductor terminations
Section 17. Circuit breakers, reclosers, switches, fuses, and other equipment
170. General
171. Arrangement
172. Application
173. Circuit breakers, reclosers, and switches containing oil
174. Switches and disconnecting devices
175. Disconnection of fuses
176. Open gaps and breaks
177. Arresters
Section 18. Switchgear and metal-enclosed bus
180. Switchgear assemblies
181. Metal-enclosed bus
Section 19. Photovoltaic generating stations
190. General
191. Location
192. Grounding configurations
193. Vegetation management
194. DC overcurrent protection
195. DC conductors
Part 2. Safety Rules for the Installation and Maintenance of Overhead Electric Supply and Communication Lines
Section 20. Purpose, scope, and application of rules
200. Purpose
201. Scope
202. Application of rules
Section 21. General requirements
210. Referenced sections
211. Number 211 not used in this edition.
212. Induced voltages
213. Accessibility
214. Inspection and tests of lines and equipment
215. Grounding and bonding
216. Arrangement of switches
217. General
218. Vegetation management
Section 22. Relations between various classes of lines and equipment
220. Relative levels
221. Avoidance of conflict
222. Joint use of structures
223. Communications protective requirements
224. Communication circuits located within the supply space and supply circuits located within the communication space
225. Electric railway construction
Section 23. Clearances
230. General
231. Clearances of supporting structures from other objects
232. Vertical clearances of wires, conductors, cables, and equipment aboveground, roadway, rail, or water surfaces
233. Clearances between wires, conductors, and cables carried on different supporting structures
234. Clearance of wires, conductors, cables, and equipment from buildings, bridges, rail cars, swimming pools, supporting structures, and other installations
235. Clearance for wires, conductors, or cables carried on the same supporting structure
236. Climbing space
237. Working space
238. Clearances at the support between specified communications and supply facilities located on the same structure
239. Clearance of vertical and lateral facilities from other facilities and surfaces on the same supporting structure
Section 24. Grades of construction
240. General
241. Application of grades of construction to different situations
242. Grades of construction for conductors
243. Grades of construction for line supports
Section 25. Structural loadings for Grades B and C
250. General loading requirements and maps
251. Conductor loading
252. Loads on line supports
253. Load factors for structures, crossarms, support hardware, guys, foundations, and anchors
Section 26. Strength requirements
260. General (see also Section 20)
261. Grades B and C construction
262. Number 262 not used in this edition.
263. Grade N construction
264. Guying and bracing
Section 27. Line insulation
270. Application of rule
271. Material and marking
272. Ratio of flashover to puncture voltage
273. Insulation level
274. Factory tests
275. Special insulator applications
276. Number 276 not used in this edition.
277. Mechanical strength of insulators
278. Aerial cable systems
279. Guy and span insulators
28. Section number 28 not used in this edition.
29. Section number 29 not used in this edition.
Part 3. Safety Rules for the Installation and Maintenance of Underground Electric Supply and Communication Lines
Section 30. Purpose, scope, and application of rules
300. Purpose
301. Scope
302. Application of rules
Section 31. General requirements applying to underground lines
310. Referenced sections
311. Installation and maintenance
312. Accessibility
313. Inspection and tests of lines and equipment
314. Grounding of circuits and equipment
315. Communications protective requirements
316. Induced voltage
Section 32. Underground conduit systems
320. Location
321. Excavation and backfill
322. Conduit, ducts, and joints
323. Manholes, handholes, and vaults
Section 33. Supply cable
330. General
331. Sheaths and jackets
332. Shielding
333. Cable accessories and joints
Section 34. Cable in underground structures
340. General
341. Installation
342. Grounding and bonding
343. Number not used in this edition.
344. Communication cables containing special supply circuits
Section 35. Direct-buried cable and cable in duct not part of a conduit system
350. General
351. Location and routing
352. Installation
353. Deliberate separations—Equal to or greater than 12 in (300 mm) from underground structures or other cables
354. Random separation—Separation less than 12 in (300 mm) from underground structures or other cables
355. Additional rules for duct not part of a conduit system
Section 36. Risers
360. General
361. Installation
362. Pole risers—Additional requirements
363. Pad-mounted installations
Section 37. Supply cable terminations
370. General
371. Support at terminations
372. Identification
373. Clearances in enclosures or vaults
374. Grounding
Section 38. Equipment
380. General
381. Design
382. Location in underground structures
383. Installation
384. Grounding and bonding
385. Identificaiton
Section 39. Installation in tunnels
390. General
391. Environment
Part 4. Work Rules for the Operation of Electric Supply and Communications Lines and Equipment
Section 40. Purpose and scope
400. Purpose
401. Scope
402. Referenced sections
Section 41. Supply and communications systems—Rules for employers
410. General requirements
411. Protective methods and devices
Section 42. General rules for employees
420. General
421. General operating routines
422. Overhead line operating procedures
423. Underground line operating procedures
Section 43. Additional rules for communications employees
430. General
431. Approach to energized conductors or parts
432. Joint-use structures
433. Attendant on surface at joint-use manhole
434. Sheath continuity
Section 44. Additional rules for supply employees
440. General
441. Energized conductors or parts
442. Switching control procedures
443. Work on energized lines and equipment
444. De-energizing equipment or lines to protect employees
445. Protective grounds
446. Live work
447. Protection against arcing and other damage while installing and maintaining insulators and conductors
Appendix A—Uniform system of clearances adopted in the 1990 Edition
Appendix B—Uniform clearance calculations for conductors under ice and wind conditions adopted in the 2007 Edition
Appendix C—Example applications for Rule 250C, Table 250-2, Table 250-3(a), and Table 250-3(b)
Appendix D—Practical Approaches to Reducing Transient Overvoltages Factors for Live Work
Appendix E—Bibliography
Annex 1—Metric tables and figures
Annex 2—Letter symbols for units
Index
A-C
C-D
D-F
F-G
H-I
I-L
L-O
O
O-R
R-S
S-T
T-U
U-W
Back cover