Code Hunter – Tables, 2017 NEC

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Code Hunter

To play this game, you need a sharp eye, a quick mind and a 2017 National Electrical Code book.

Questions

1) Which table list minimum cover requirements for underground wiring methods 1000 volts or less?

A) Table 300.5
B) Table 300.50
C) Table 310.104(A)
D) Table 312.6(A)

2) Which table lists the volume allowances required per conductor for outlet, device and junction boxes?

A) Table 312.6(A)
B) Table 312.6(B)
C) Table 314.16(A)
D) Table 314.16(B)

3) Which table lists the minimum size equipment grounding conductors for grounding equipment?

A) Table 250.66
B) Table 250.102(C)
C) Table 250.122
D) Table 310.15(B)(16)

4) Which table lists the percent of cross sectional fill permitted in conduit and tubing for conductors and cables?

A) Chapter 9, Table 1
B) Chapter 9, Table 2
C) Chapter 9, Table 4
D) Chapter 9, Table 10

5) Which table lists the maximum rating or setting of motor branch-circuit short circuit and ground fault protective devices?

A) Table 430.22(E)
B) Table 430.37
C) Table 430.52
D) Table 430.250

Answers

1) A, Table 300.5. With five columns and seven rows, this table is a comprehensive guide to the required amount of cover over raceways, cables and direct burial conductors. Be sure to read the notes under the table, as they contain mandatory requirements.

2) D, Table 314.16(B). This table assigns the required free space within a box for each conductor sized 18 AWG to 6 AWG. These space requirements are also used for the required volume for devices, equipment, clamps, supports, etc. as described in the text of 314.16(B).

3) C, Table 250.122. The minimum size equipment grounding conductors are chosen based on the rating or setting (in amperes) of the overcurrent device in the circuit ahead of the equipment, conduit, etc.

4) A, Chapter 9, Table 1. This table is referenced in the Chapter 3 articles for conduits and tubing. The reference is found in each article in the “.22” section. For example, for rigid metal conduit (RMC) the permissible number of conductors reference is found in 344.22.

5) C, Table 430.52. This table contains the percentage multipliers used to select nontime delay fuses, dual element time delay fuses, instantaneous trip breakers, and inverse time breakers used for motor circuit protection. The value in the table is multiplied by the full load current to determine the maximum allowable size of the overcurrent protective device.

Bonus question

Q: Field-installed grounding and bonding terminals for swimming pool installation connections in a wet or corrosive location are required to be made of copper, copper alloy, or stainless steel?

A: True. Section 680.7 requires that all grounding and bonding terminations for swimming pools be identified for use in wet and corrosive environments, and if field-installed, must be one of the specified metals. These connectors must also be listed for direct burial.


Christel Hunter is director of codes and standards for Cerro Wire. Chris is a senior associate member of IAEI and serves as a board member for the Southern Nevada Chapter of IAEI and the Las Vegas Section of IEEE. Chris also serves on NEC CMP-6, and the CE Code Part I committee, Sections 4 and Section 12.

Randy Hunter is an instructor and consultant specializing in electrical code and installations, and co-owner of Hunter Technical Services. He holds twelve inspections certifications from IAEI, ICC and IAPMO. He is the IAEI Southwestern Section secretary and Southern Nevada IAEI Chapter president. Randy has been a master electrician since 1988.

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Christel Hunter is director of codes and standards for Cerro Wire. Chris is a senior associate member of IAEI and serves as a board member for the Southern Nevada Chapter of IAEI and the Las Vegas Section of IEEE. Chris also serves on NEC CMP-6 and CMP-7, the CE Code Part I committee and Sections 4 and 12 subcommittees, and many other industry committees. She is a certified standards professional, master electrician, and LEED accredited professional. Randy Hunter has over thirty years’ experience in the electrical industry including working in the government, contracting and manufacturing sectors. He is an instructor and consultant specializing in electrical code and installations, and co-owner of Hunter Technical Services. He holds twelve inspections certifications from IAEI, ICC and IAPMO. He is the IAEI Southwestern Section secretary, Southern Nevada IAEI Chapter president, former principal member on NEC CMP-6 and CMP-17, voting member of UL 1563 (Electric Spas, Equipment Assemblies, and Associated Equipment), and a former member of the IAPMO Product Certification Committee and Standards Review Committee. Randy has served on several Southern Nevada local code committees and electrical licensing committees and has been a master electrician since 1988. Prior to that, he designed and built computer numerically controlled (CNC) machine tools.