Code Hunter — Ratings (2017 NEC)


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

(Fill-in-the-blank questions are looking for the exact words) used in the NEC).

1. Branch circuits recognized by this article shall be rated in accordance with the maximum permitted ampere rating or _________________ of the overcurrent device.
2. The maximum current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature ______________.
3. Separately installed pressure connectors shall be used with conductors at the ampacities not exceeding the ampacity at the listed and identified temperature rating of the _________.
4. Throughout this Code, the voltage considered shall be that at which the circuit operates.  The __________ rating of electrical equipment shall not be less than the nominal voltage of a circuit to which it is connected.
5. The feeder or branch-circuit disconnecting means shall have a rating of not less than the __________ load to be supplied, …
6. Standard ampere ratings for fuses and inverse time circuit breakers are found in:
7. The __________ number of branch circuits shall be determined from the total calculated load and the size or rating of the circuits used.
8. For ground-fault protection of equipment, the rating of the service disconnect shall be considered to be the rating of the largest fuse that can be installed or the highest continuous current trip setting for which the actual overcurrent device installed in a circuit breaker is rated or can be adjusted.
9. Where conductors of higher ampacity are used for any reason, the ampere rating or setting of the specified overcurrent device determines the circuit rating.
10. The ampere rating of a range receptacle is permitted to be based on the demand load of a single range as specified in Table 220.55.

Bonus Question

Interrupting rating is defined as the highest current at rated voltage that a device is identified to interrupt under actual operating conditions.


Previous articleDealing with Currents in PV Systems — Just a little more math
Next articleNew Guides for NFPA 78 and 1078
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.