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 word(s) used in the NEC.)

The Questions

1. Access and _____­ shall be provided and maintained about all electrical equipment to permit ready and safe operation and maintenance of such equipment.

A. Clearance

B. Clear space

C. Working space

D. Dedicated space

2. The purpose of this Code is the _____­ safeguarding of persons and property from hazards arising from the use of electricity.

A. Practical

B. Effective

C. Complete

D. Necessary

3. Industrial machinery with safety _____­ circuits shall have surge protection installed.

A. Stop

B. Control

C. Interlock

D. Disconnect

4. Where the highest continuous current trip setting for which the actual overcurrent device installed in a circuit breaker is rated or can be adjusted is 1,000 A or higher, arc energy reduction means must be provided.

A. True

B. False

5. Permanent safety signs are required to be installed to give notice of electrical shock hazard risks to persons using or swimming near a boat dock or marina.

A. True

B. False

6. Entrances to rooms and other guarded locations that contain exposed live parts shall be marked with conspicuous warning signs forbidding _____­ persons to enter.

A. Qualified

B. Untrained

C. Unqualified

D. Management

7. External surfaces of pipeline and vessel heating equipment that operate at temperatures exceeding _____­ shall be physically guarded, isolated, or thermally insulated to protect against contact by personnel in the area.

A. 45°C (113°F)

B. 60°C (140°F)

C. 75°C (167°F)

D. 90°C (194°F)

8. Equipment that performs the rapid shutdown functions, other than _____­ devices such as listed disconnect switches, circuit breakers, or control switches, shall be listed for providing rapid shutdown protection.

A. Active

B. Passive

C. Control

D. Initiation

9. Emergency system(s) overcurrent devices shall be selectively coordinated with all _____­ overcurrent protective devices.

A. Load-side

B. Emergency

C. Supply-side

D. Inverse-time

10.Cutouts shall be located so that they may be readily and safely operated and re-fused, and so that the _____­ of the fuses does not endanger persons.

A. Exhaust

B. Location

C. Operation

D. Explosion

BONUS Question

Q: Is illumination required for working spaces containing battery systems? See for the answer beginning in April.


1. C, Working space. Section 110.26 requires that access and working space be provided and maintained for all electrical equipment. If the equipment is likely to require examination, adjustment, servicing, or maintenance while energized, there are specific working space depth, width, and height requirements based on the equipment voltage and the surrounding conditions.

2. A, Practical. Section 90.1(A) tells us that the purpose of the National Electrical Code is provide practical safeguarding of persons and property from the hazards of electricity. It goes on to say that the NEC is not intended as a design specification or an instruction manual for untrained persons. NEC requirements are considered to be the minimum for safety, and additional design considerations are likely to be required to satisfy needs for efficiency, convenience, and good service.

3. C, Interlock. This requirement is new for the 2017 NEC and is found in 670.6 Surge Protection for industrial machinery. Safety interlock circuits are used to shut off power to machinery, control worker access to moving parts, or prevent a machine from starting or operating when a guard or other safety component is open or disengaged. Safety interlock devices often have electronic components that can be damaged by power surges.

4. B, False. Section 240.87 requires arc energy reduction means be provided for circuit breakers with a trip rating of 1,200 A or higher. Methods include zone-selective interlocking, energy-reducing maintenance switching, and several other options. A new section 240.67 was added in the 2017 NEC with an effective date of January 1, 2020, to provide similar requirements for fuses.

5. A, True. In section 555.24, a new signage requirement was added to the 2017 NEC to warn people that electrical currents may be present in the water around boat docks and marinas. Electric shock drowning is a serious risk for people swimming around these locations, and the signs are required to be clearly visible from all approaches to a marina or boatyard facility.

6. C, Unqualified. Section 110.27(C) requires signs warning unqualified persons to stay out of rooms with exposed live parts, and these signs must warn of the hazards using effective words, colors, symbols, or any combination thereof; be permanently affixed and not handwritten; and be of sufficient durability to withstand the environment involved.

7. B, 60°C (140°F). This requirement is found in section 427.12 Thermal Protection. Article 427 contains requirements for Fixed Electric Heating Equipment for Pipelines and Vessels. The equipment must also be protected from physical damage and be identified by appropriate caution signs or markings.

8. D, Initiation. Section 690.12(D) is new for the 2017 NEC and is part of the requirements for rapid shutdown of PV systems on buildings. The requirement for rapid shutdown first appeared in the 2014 NEC, and it is intended to de-energize the PV circuits in order to reduce the shock hazard for emergency responders.

9. C, Supply-side. Section 700.32 requires that overcurrent devices on emergency systems be selectively coordinated with all overcurrent devices on the supply side, including those on the normal and alternate power source systems. Selective coordination limits outages to the smallest possible area of the electrical system.

10. A, Exhaust. This requirement is found in 490.21(C)(1) Distribution Cutouts and Fuse Links—Expulsion Type—Installation. Article 490 contains requirements for Equipment Over 1,000 volts, Nominal. The language in 490.21(C)(1) goes on to say that distribution cutouts are not to be used indoors, underground, or in metal enclosures.

BONUS Answer

Yes. Section 480.10(G) requires illumination be provided for battery system working spaces. The illumination is not allowed to be controlled by automatic means only, but it is allowed to be provided by an adjacent light source.

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, the IEEE Standards Association Standards Board, and the Las Vegas Section of IEEE. Chris also serves on NEC CMP-6. Chris is a Certified Standards Professional, Master Electrician, and LEED Accredited Professional.

Randy Hunter is an instructor and consultant specializing in electrical Code and installations, and co-owner of Hunter Technical Services. He holds ten inspections certifications from IAEI and ICC. He is the IAEI Southern Nevada Chapter president and 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.


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