Installation Of Fire Alarm System Dreamstime Xxl 137109928

National Electrical Code

The NEC and Fire Alarm Systems — Part 3

Dec. 1, 2020

Summarizing Part III of Art. 760

Part III of Art. 760 of the National Electrical Code (NEC) provides the requirements for power-limited fire alarm (PLFA) circuits. The power sources must be one of three types (all listed) [760.121(A)]:

PLFA or Class 3 transformer.
PLFA or Class 3 power supply.
Equipment marked to identify the PLFA power source.

Other highlights include:

The branch circuit supplying the fire alarm equipment can’t supply other loads [760.121(B)].
Conductors and equipment on the supply side of the PLFA power source must be installed per the appropriate requirements of Part II of 760 and of Chapters 1 through 4 [760.127].
On the load side of the PLFA power source, use wiring methods and materials that comply with 760.130.
PLFA cables installed in buildings must comply with 760.135(A) through (J). Most of the requirements are location specific. For example, risers in vertical runs must be Type FPLP or FPLR cable [760.135(D)(1)].
You must keep PLFA conductors separate from other kinds of conductors using the methods described in 760.136(A) through (G).
You can use the cable substitutions provided in 760.154(A).

About the Author

Mark Lamendola

Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.

Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.

Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.