What is Class 4 Fault Managed Power?

Class 4 is a new circuit term defined in the 2023 edition of the NFPA 70, commonly referred to as the National Electrical Code (NEC). Class 4 is defined in a new Article 726 that is part of chapter 7 which deals with special conditions. Class 4 systems are referred to as “Fault Managed Power Systems” (FMPS). These systems are not power limited and can deliver hundreds or thousands of watts of power. The voltage can be up to 450V AC or DC which sounds dangerous. However, these systems intelligently limit the amount of energy that can go into a fault. Limiting the fault energy mitigates the risk of shock or fire and allows the installation of Class 4 circuits using methods like power-limited circuits. Attendees will learn how Class 2 and Class 4 circuits can be used to deliver more than 100W at distances above 100m. How a DC based power infrastructure can save on CapEx (material and labor costs), control their energy use to reduce OpEx, and use less materials for less embodied carbon per project. VoltServer is the pioneer of fault managed power systems and has thousands of installations using this technology under existing electrical codes supporting applications in wireless communications, intelligent buildings, and controlled environment agriculture (CEA).

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