NFPA 70-2023 Changes
(C) Identification of Ungrounded Conductors
(1) Branch Circuits Supplied from More Than One Nominal Voltage System.
Changes were made to add clarity and not change the intent of this section.
The term “voltage class” was removed and replaced with “nominal system voltage”. The submitter of the public input pointed out that the language that was added in NEC 2020 made this requirement more confusing. NEC 2020 added “voltage class” but there is no definition of what this term means. The submitter suggested replacing this with “nominal voltage” as it is a defined term in Article 100. The submitter also noted that taken literally, the language found in NEC 2020 can be interpreted as meaning that it is needed to identify each ungrounded conductor of each separately derived system on a premise. The changes made add clarity that this is not the case when the nominal system voltages from each separately derived system are the same.
From Article 100, the definition of Nominal Voltage is as follows:
“A nominal value assigned to a circuit or system for the purpose of conveniently designating its voltage class (e.g., 120/240 volts, 480Y/277 volts, 600 volts).”
Keep in mind that the actual voltage at which a circuit operates can vary from the nominal voltage of that system within a range that permits satisfactory operation of equipment.