2017 NEC: Special Conditions And Communication Systems—Significant Changes in the 2017 NEC, Part 10

By Michael Johnston | May 15, 2017




This is the final part in a series that reviews some of the more significant revisions and new requirements included in the 2017 National Electrical Code (NEC). This article looks at more rule changes for special equipment covered in NEC chapters 7 and 8. Visit for this full series.

700.2 Definitions

A new definition of “directly controlled luminaires” was added to 700.2. Article 700.24 was added during the 2014 revision cycle. It permits directly controlled luminaires as emergency lighting, but the term was not defined. These luminaires may be dimmed but must be driven to full illumination upon loss of normal power.

700.3(C) and 701.3(C) Maintenance

Sections 700.3(C) and 701.3(C) have been revised to require maintenance on all emergency and legally required system equipment. Electrical equipment in these emergency and legally required standby systems must be maintained in accordance with the manufacturer’s instructions and NFPA 70B, Standard for Electrical Equipment Maintenance.

700.10(A) Identification of Emergency System Wiring

Where boxes or enclosures are not encountered, exposed cable or raceway systems must be marked as a component of an emergency circuit or system at intervals not to exceed 25 feet. Receptacles supplied from the emergency system must have a distinctive color or marking on the cover plates or the receptacles themselves. The NEC does not specify a color, but red is often used.

702.12(C) Power Inlets Rated 100 Amperes or Greater

A new Section 702.12(C) requires power inlets rated 100 amperes (A) or greater for portable generators in optional standby systems to be listed for the intended use. Power inlets must be equipped with an interlocked disconnecting means. Exceptions are included for inlet devices that are rated as a disconnecting means and for supervised industrial installations.

Article 706 Energy Storage Systems

Energy storage is becoming essential to meeting load-leveling capabilities along with demand response as it relates to smart grid initiatives and Department of Energy mandates on energy use. Associated and emerging technology coupled with the need for energy storage systems (ESSs) is growing rapidly, and new Article 706 provides requirements for ESSs in the NEC. Article 706’s scope specifically limits application to permanently installed ESSs over 50 volts (V) AC or 60V DC to correlate with existing requirements. This article correlates multiple other energy storage requirements in the NEC.

708.10(A)(2) COPS Receptacle Identification

Nonlocking-type, 125V, 15- and 20A receptacles in buildings with critical operations power systems (COPS) and other power systems must have an illuminated face or an indicator light to signal there is power to the receptacle. All COPS-supplied receptacles installed where other power systems are present must have a distinctive color or marking on the cover plates or receptacles themselves so as to be readily identifiable.

Article 712 DC Microgrids

New Article 712 provides ­installation requirements for DC microgrids. DC microgrids eliminate power conversion resulting in more efficient use of renewable energy sources. DC power sources include AC-DC converters (rectifiers), bidirectional DC-AC inverters/converters, photovoltaic systems, wind generators, ESSs (including batteries) and fuel cells.

725.144 Transmission of Power Over Limited Energy Cables

A new Section 725.144 was added to address requirements for Class 2 and Class 3 circuits that transmit power and data to a powered device. Table 725.144 is new and lists permitted ampacities based on conductor types, sizes, number of cables bundled and ambient temperatures. Conductors that supply power for data circuits must be copper.

728.5(C) Fire-Resistive Cable Installation

Section 725.5(C) has been modified to mandate that raceway fill for each system comply with the listing requirements for the system and not be greater than the fill permitted in Table 1, Chapter 9.

Article 840 Part VI and 840.160

A new Part VI in Article 840 addresses power over ethernet (PoE). Section 840.160 requires compliance with section 725.144 for PoE installations. A new Section 840.170 provides listing requirements for PoE power sources.

NECA and the Electrical Training ALLIANCE authored the 2017 NEC Significant Changes textbook. Obtain a copy at For more information, visit

About The Author

A man, Mike Johnston, in front of a gray background.

Michael Johnston

NECA Executive Director of Codes and Standards

JOHNSTON is NECA’s executive director of codes and standards. He is a member of the NEC Correlating Committee, NFPA Standards Council, IBEW, UL Electrical Council and NFPA’s Electrical Section. Reach him at [email protected].






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