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100 Definition – Class 4 Circuits

New

Change Summary

  • Definition of Class 4 circuits has been added to the NEC. Class 4 circuits are new, and the definition correlates with new article 726 – Class 4 Power Systems.

NEC®Text

100 Defintions
Class 4 Circuit. The portion of the wiring system between the load side of a Class 4 transmitter and the Class 4 receiver or Class 4 utilization equipment, as appropriate. Due to the active monitoring and control of the voltage and current provided, a Class 4 circuit considers safety from a fire initiation standpoint and provides acceptable protection from electric shock. (726) (CMP-3)
Informational Note: A Class 4 circuit is also commonly referred to as a fault-managed power circuit.

Material taken from the National Electric Code. is reprinted with permission from NFPA 70., 2023 edition. National Electrical Code®, Copyright 2022, National Fire Protection Association, Quincy, MA. All rights reserved.

Expert Analysis

The NEC previously addressed Class 1, 2 and 3 Power systems and now the new Class 4 Power System. There is more info given in the NEC to include Cass 4 Devices, Receivers, Transmitters, etc. If you are involved in this work, please reference Article 726 in this guide and the actual NEC 70.

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