This article reviews changes in Chapter 4, Equipment for General Use, in the 2017 edition of the National Electrical Code (NEC). Visit www.ecmag.com/2017-NEC-significant-changes for this full series.
422.16(B)(2) Built-in Dishwashers and Trash Compactors
Flexible cords supplying trash compactors are permitted to be between 3–4 feet long. A longer, flexible cord to facilitate connection for dishwashers in an adjacent space is permitted to be between 3–6½ feet long. The receptacle for a trash compactor must be located in the space occupied by the appliance or adjacent, and the receptacle for a built-in dishwasher must be located in the space adjacent to the space occupied by the dishwasher.
422.31(A) and (B) Appliance Disconnects
Permanently connected appliances rated at not over 300 volt-amperes or 1/8 horsepower (hp) and motor operated appliances over 1/8 hp now require disconnects within sight or lockable in accordance with 110.25. The provisions for locking shall remain in place with or without the lock installed. This will require an identified accessory for circuit breakers.
424.99(C) Installation Under Floor Covering
A grounding braid or sheath is required for all heating panels and heating panel sets installed under floor covering. Ground-fault circuit interrupter (GFCI)protection is required for all heating panels and heating panel sets installed under floor covering. The combination of a grounding braid or sheath and GFCI increases protection from shock.
Article 425—Industrial Process Heating Equipment
Article 425 is added to cover fixed industrial process heating employing electric resistance or electrode heating technology. Article 425’s requirements are similar to those in existing Article 424. It does not apply to heating and room air conditioning for personnel spaces, fixed heating equipment for pipelines/vessels, and induction and dielectric heating equipment and other special applications.
430.99 CC Available Fault Current Documentation
Section 430.99 is new and requires documentation of the amount of available short-circuit current at a motor control center and the date the calculation was made. This information must be documented and available for the authority having jurisdiction to ensure compliance with 430.98(A). While a label or marking of available short-circuit current is not required on the motor control center, it may be the most feasible method of complying with this new requirement.
430.130(A)(4) Circuits Containing Power Conversion Equipment
New Section 430.130(A)(4) replaces the previous informational note to address the type of protective device for circuits containing power conversion equipment.
Where an instantaneous trip circuit breaker or semiconductor fuses are used, they must be an integral part of a single listed assembly. This revision aligns the NEC with the applicable product standard, UL 508C.
440.9 Grounding and Bonding
Section 440.9 now requires a “wire-type” equipment grounding conductor (EGC) for outdoor portions of metallic raceway systems that use nonthreaded fittings installed on a roof. Physical damage caused by activities on a roof combined with the weather can cause nonthreaded connectors and couplings to open, eliminating the fault return path on the metal raceway.
While this is a significant revision, there will be little impact on the industry because the vast majority of EMT installations include a “wire-type” EGC by specification without regard to where the EMT is installed.
440.65 Protection Devices for Room Air Conditioners
Section 440.65 was retitled “Protection Devices.” The permitted protective devices are a leakage-current detection interrupter (LCDI), an arc-fault circuit interrupter (AFCI) or a heat-detecting circuit interrupter (HDCI). An HDCI incorporates all of the protection functions of an LCDI and includes a thermal detecting function to the air conditioner’s compressor against overheating.
445.13(B) Ampacity of Conductors
New Section 445.13(B) clarifies that generator-supplied conductors on the load side of an overcurrent protective device are not required to be sized at 115 percent of the generator nameplate current. Generator-supplied conductors on the load side of an overcurrent protective device (OCPD) may be applied in accordance with 240.21(B). The 115 percent rule applies only to conductors from the generator output terminals to an OCPD.
445.18 Disconnecting Means and Shutdown or Prime Mover
Section 445.18 has been separated into three first-level subdivisions to provide a more logical layout. Section 445.18(A) requires one or more disconnecting means (110.25) that simultaneously open all ungrounded conductors for all generators other than cord- and plug-connected portable generators. Section 445.18(B) requires a means to shut down the prime mover, disabling all prime mover start control circuits, rendering the prime mover incapable of starting. Section 445.18(C) provides clarity for required disconnects where generators are installed in parallel.
About The Author
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]