Inside The Panelboard: Does This Installation Comply With the NEC?

By Mark C. Ode | Dec 15, 2017

A friend recently sent me an email with this picture (right) of a manual fire alarm pull station mounted on the side of an electrical panelboard. My friend was inspecting the fire alarm system and was accompanied by the electrician who had installed both the fire alarm and electrical systems. The electrician stated that the power-limited fire alarm circuit had been installed in electrical metallic tubing (EMT), inside the panelboard, to supply the manual pull station. He stated that there was no other mounting option for the pull station within 5 feet of the exit door. My friend wanted my thoughts on the installation and whether it complied with the National Electrical Code (NEC).

To answer the question, I accessed the 2016 NFPA National Fire Alarm Code 
( to determine the requirements for manual fire alarm pull stations. Section requires manual pull stations to be located within 5 feet of each exit doorway on each floor of a building. Section also requires additional manual fire alarm boxes to be installed so the travel distance to the nearest manual fire alarm box will not exceed 200 feet, measured horizontally on the same floor.

No exceptions to the section within the National Fire Alarm Code required a manual pull station within 5 feet of exit doors. The picture shows the panelboard on a block wall located immediately adjacent to an exit door, and there wasn’t enough wall space to mount the pull station adjacent to the door; thus, the pull station was mounted to the side of the panelboard. The power-limited fire alarm circuit conductors or cables were installed in EMT in the conductor pull area of the panelboard. The installation pictured would certainly comply with the National Fire Alarm Code requirements.

The next part of the equation was to determine if the installation complied with the NEC. Two sections of the Code came to mind immediately. The first is 760.136, covering separation from electric light, power, Class 1, nonpower-limited fire alarm circuits, and medium-power network-powered broadband communications circuit conductors from power-limited fire alarm systems. The intent is to ensure power-limited fire alarm circuit cable and conductors are “not installed in any cable, cable tray, compartment, enclosure, manhole, outlet box, device box, raceway, or similar fitting with conductors of electric light, power, Class 1, non–power-limited fire alarm circuits, and medium-power network-powered broadband communications circuits, unless permitted by 760.136(B) through (G).”

Keeping these power-limited fire alarm conductors and cables separated from power circuits will ensure that a short circuit between the two systems will not result in higher voltage and current being imposed on the power limited circuits.

Section 760.136(C) permits raceways to be installed within enclosures as follows: “In enclosures, power-limited fire alarm circuits shall be permitted to be installed in a raceway within the enclosure to separate them from Class 1, non–power-limited fire alarm, and medium-power network-powered broadband communications circuits.”

Installing a raceway inside of a panelboard is acceptable in 725.136(C); however, there are additional issues for the panelboard enclosure. Panelboards are covered in and consist of busbars (buses), conductor terminals, and automatic overcurrent protective devices, such as circuit breakers, as covered in Article 100 for definitions. They are designed to be installed in dead-front cabinets, cutout boxes or identified enclosures as covered in 408.38.

Article 312 covers cabinets, cutout boxes and meter socket enclosures. The wiring space within the enclosure consists of side-wiring spaces, side gutters or side-wiring compartments designed to provide enough room for the conductors and to terminate on the overcurrent protective devices. The wiring spaces in the enclosures can contain splices, taps or feed-through conductors as well as power monitoring equipment, as long as the installation complies with 312.8.

The section states: “The wiring space of enclosures for switches or overcurrent devices shall be permitted for conductors feeding through, spliced, or tapping off to other enclosures, switches, or overcurrent devices where all of the following conditions are met: (1) The total of all conductors installed at any cross section of the wiring space does not exceed 40 percent of the cross-sectional area of that space. (2) The total area of all conductors, splices, and taps installed at any cross section of the wiring space does not exceed 75 percent of the cross-sectional area of that space.”

While the text doesn’t specifically address a raceway, if the raceway doesn’t exceed the area requirement in 312.8(A) and the inspector permits the installation, there shouldn’t be an issue with the installation in question.

About The Author

ODE is a retired lead engineering instructor at Underwriters Laboratories and is owner of Southwest Electrical Training and Consulting. Contact him at 919.949.2576 and [email protected]





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