Re-using the shell of a fire panel is a conundrum that recently struck this integrator, who was replacing an existing, outdated control with a new addressable panel in a nursing facility. This old panel was very large and had a lot of circuit wiring piped into it.
Q: “I’d like to locate the new panel, enclosure and all, inside this space. Do you know of any reason I cannot install the new fire alarm control panel inside the empty cabinet of the old control panel?”
A. Let’s think this through logically: First, don’t be tempted to remove the circuit board from the new addressable control panel and mount it in the existing cabinet, no matter what model or manufacturer. The metal enclosure with the addressable panel was put through the listing process with the electronics mounted inside it and was tested for lightning suppression with the conduit knockouts installed in locations approved by the manufacturer. These wiring entry locations help maintain a separation from non-power limited wiring. The listed panel must be treated as the single assembly described in the installation instructions.
Next, look at the new panel’s instructions and how NFPA 72 limits your choices of indoor locations. NFPA 72 will set the basic ambient conditions under which it may be installed — for example, you should not install the panel where the temperature will exceed 100° or 32° F, nor in damp, dirty or corrosive environments. Even areas where the temperature fluctuates wildly within the allowable range or where it may be subject to vibration can shorten the panel’s reliable lifespan; so, unless the manufacturer’s written instructions provided with the panel allow different ambient conditions other than these provided by NFPA 72, you will not be permitted to get too creative.
Next, consider the National Electrical Code (NEC) generic rules for boxes and raceways. You will not make any splices that are not within the new addressable panel or in electrical junction boxes with their covers attached. Maintaining a code-compliant installation should be your goal, even if the larger panel’s door is removed.
Finally, is there anything similar already permitted by the codes? What if your addressable panel’s location was subject to occasional water spray, say during weekly clean-ups. To protect it, the NEC would specify protecting your panel with a special water resistant (i.e. NEMA-4) rated enclosure that is sealed with a gasketed door. Your effort to provide less downtime (and better protect the system against tampering) is no less valid than using a NEMA-4 rated enclosure to protect your panel from occasional splashed water.
Since this project is not a replacement of like equipment, you will have to submit plans to the local authority having jurisdiction for approval. In the documentation you provide the local code authority, simply explain how you are going to use the existing cabinet space to install the new control panel. It is better to have this discussion out of the way before the final inspection.
Elevator Smoke Detector Compliance
My second question comes from an installer with a long-time customer who has added a new wing with a second floor to an existing single-story office building. An elevator was installed in the new wing to serve the second floor. Since the existing fire alarm system was not addressable, the installer used four-wire, relay-based smoke detectors to provide elevator recall, with an end-of-line power supervision relay after each recall detector. Obviously, the two elevator lobby smoke detectors’ relays are not going to be within three feet of the elevator equipment.