Code Change Summary: New Article covers Class 1 Power-Limited Circuits and Class 1 Power-Limited Remote-Control and Signaling Circuits.
In the 2023 NEC®, previous requirements for Class 1 circuits were removed from Article 725 and relocated to new Article 724.
A Class 1 circuit is the portion of the wiring system between the load side of the Class 1 power source and the connected equipment.
According to new Section 724.40, Class 1 circuits are limited to 30 volts and 1000 volt-amperes. Previous editions of the NEC® described Non-power limited Class 1 remote-control and signaling circuits in Article 725. Technically, these circuits are actually “branch circuits”. Since the requirements for branch circuits are covered in NEC® Chapters 1-4, they are not covered in new Article 724.
This change warranted the need to revise the definition of a Class 1 Circuit during the 2023 code cycle.
The previous definition described wiring between the load side of an overcurrent device or power-limited supply and the connected equipment. The new definition eliminates “overcurrent device” from the description since the wiring from the load side of an overcurrent device to the outlet where equipment is connected is technically a “branch circuit” which is also defined in Article 100.
Some highlights from new Article 724 include:
(A) Point of Supply. Overcurrent devices shall be located at the point where the conductor to be protected receives its supply.
(B) Feeder Taps. Class 1 circuit conductors shall be permitted to be tapped, without overcurrent protection at the tap, where the overcurrent device protecting the circuit conductor is sized to protect the tap conductor.
(C) Branch-Circuit Taps. Class 1 circuit conductors 14 AWG and larger that are tapped from the load side of the overcurrent protective device(s) of a controlled light and power circuit shall require only short-circuit and ground-fault protection and shall be permitted to be protected by the branch-circuit overcurrent protective device(s) where the rating of the protective device(s) is not more than 300 percent of the ampacity of the Class 1 circuit conductor.
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 2023 NEC® edition of NFPA 70.
2020 Code Language:
This article did not exist.
2023 Code Language:
724.1 Scope. This article covers Class 1 circuits, including power-limited Class 1 remote-control and signaling circuits, that are not an integral part of a device or utilization equipment.
724.45 Class 1 Circuit Overcurrent Device Location. Overcurrent devices shall be located as specified in 724.45(A) through (E).
(A) Point of Supply. Overcurrent devices shall be located at the point where the conductor to be protected receives its supply.
(B) Feeder Taps. Class 1 circuit conductors shall be permitted to be tapped, without overcurrent protection at the tap, where the overcurrent device protecting the circuit conductor is sized to protect the tap conductor.
(C) Branch-Circuit Taps. Class 1 circuit conductors 14 AWG and larger that are tapped from the load side of the overcurrent protective device(s) of a controlled light and power circuit shall require only short-circuit and ground-fault protection and shall be permitted to be protected by the branch-circuit overcurrent protective device(s) where the rating of the protective device(s) is not more than 300 percent of the ampacity of the Class 1 circuit conductor.
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