Code Change Summary: A new definition of Fault-Managed Power has been added to Article 100.
In the 2023 NEC®, Fault-Managed Power (FMP) is defined in Article 100 as a powering system that monitors for faults and controls current delivered to ensure fault energy is limited.
This new definition aligns with new Article 726 which covers Class 4 Fault-Managed Power Systems.
In the electrical industry, “Fault-Managed Power” has also been referred to as Packet Energy Transfer (PET), Digital Electricity (DE), Pulsed Power, and Smart Transfer Systems. A fault-managed power circuit is also referred to as a Class 4 circuit.
According to informational note No. 1 in new Article 726, Section 726.1, Class 4 fault-managed power systems consist of a Class 4 power transmitter and a Class 4 power receiver connected by a Class 4 cabling system. These systems are characterized by monitoring the circuit for faults and controlling the source current to ensure the energy delivered into any fault is limited.
Instead of limiting the power source output to a certain threshold such as in Class 2 and Class 3 systems, the Fault-Managed Power system monitors the circuit in real time and limits the power available during a fault event. Communication occurs between the receiver and the transmitter and if all conditions are safe, power is delivered to the load. If a fault is detected, the FMP system will halt transmission within a fraction of a second.
Since power is only limited when a fault is detected, the FMP system is ideal for powering higher loads across extremely long distances.
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 definition did not exist.
2023 Code Language:
N Fault-Managed Power (FMP). A powering system that monitors for faults and controls current delivered to ensure fault energy is limited. (726)
Based on the 2023 NEC, which of the following is true?
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