210.6(C) 277 Volts to Ground.
Code Change Summary: Revised code language regarding equipment permitted to be supplied from 277-volt circuits.
In the 2020 NEC®, Section 210.6(C) was basically cleaned up and modernized to improve its usability. This section provides a list of items that are permitted to be supplied by circuits exceeding 120 volts between conductors but not exceeding 277 volts to ground which in most cases will be the typical 277-volt branch circuit.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2020 NEC® edition of NFPA 70.
2017 Code Language:
210.6(C) 277 Volts to Ground. Circuits exceeding 120 volts, nominal, between conductors and not exceeding 277 volts, nominal, to ground shall be permitted to supply the following:
(1) Listed electric-discharge or listed light-emitting diode type luminaires
(2) Listed incandescent luminaires, where supplied at 120 volts or less from the output of a stepdown autotransformer that is an integral component of the luminaire and the outer shell terminal is electrically connected to a grounded conductor of the branch circuit
(3) Luminaires equipped with mogul-base screw shell lampholders
(4) Lampholders, other than the screw shell type, applied within their voltage ratings
(5) Auxiliary equipment of electric-discharge lamps
Informational Note: See 410.137 for auxiliary equipment limitations.
(6) Cord-and-plug-connected or permanently connected utilization equipment
2020 Code Language:
210.6(C) 277 Volts to Ground. Circuits exceeding 120 volts, nominal, between conductors but not exceeding 277 volts, nominal, to ground shall be permitted to supply cord-and-plug-connected or permanently connected utilization equipment, or the following types of listed luminaires:
(1) Electric-discharge luminaires with integral ballasts
(2) LED luminaires with LED drivers between the branch circuit and the lampholders
(3) Incandescent or LED luminaires, equipped with medium-base or smaller screw shell lampholders, where the lampholders are supplied at 120 volts or less from the output of a stepdown autotransformer, LED driver, or other type of power supply that is an integral component of the luminaire
Informational Note: See 410.90 for requirements regarding the connection of screw shell lampholders to grounded conductors.
(4) Luminaires equipped with mogul-base screw shell lampholders
(5) Luminaires equipped with lampholders, other than the screw shell type, when used within their voltage ratings of their lampholders
(6) Luminaires without lampholders
Informational Note: Luminaires with nonserviceable LEDs are examples of luminaires without lampholders.
(7) Auxiliary equipment of electric-discharge or LED-type lamps
Informational Note: See 410.137 for auxiliary equipment limitations.
(8) Luminaires converted with listed retrofit kits incorporating integral LED light sources or accepting LED lamps that also conforms with 210.6(C)(1), (C)(2), (C)(3), (C)(4), or (C)(5)