System Sensor SSM24-6 6-Inch 24VDC Signal Bell
Overview
The System Sensor SSM24-6 is a 6-inch electromechanical signal bell built for 24VDC fire alarm notification circuits — the kind of straightforward, mechanically reliable audible appliance still specified in commercial and institutional buildings where a loud, distinctive alarm tone is the requirement rather than a synchronized strobe pattern. The SSM24-6 (often searched as SSM24 6) fits into conventional or addressable fire alarm control panel circuits and is rated for a wide operating temperature range, making it viable in unconditioned mechanical rooms, stairwells, and covered outdoor areas as well as standard office space.
Key Features
- 24VDC Operation: Matches the standard notification appliance circuit (NAC) voltage used on most commercial fire alarm control panels, so the SSM24-6 wires directly into existing NAC wiring runs without a separate power supply or voltage conversion.
- 6-Inch Bell Size: A larger gong diameter than compact 4-inch signal bells, delivering a lower-pitched, more penetrating tone that carries further in large open areas like warehouses, gymnasiums, and assembly halls.
- Wide Operating Temperature Range (–31°F to 140°F): Rated for installation in spaces without climate control — parking structures, loading docks, unconditioned mechanical rooms — where standard indoor-only notification devices would be out of spec.
- Wall, Ceiling, or Rack Mount: The SSM24-6 is not locked into a single mounting orientation, giving installers flexibility to match existing box locations or code-driven placement requirements without swapping hardware families.
- 3-Year Warranty: A defined coverage term on the electromechanical bell assembly, relevant when budgeting lifecycle costs on a notification circuit that may run continuously for years between test cycles.
Integration & Compatibility
The SSM24-6 is designed to operate on standard 24VDC notification appliance circuits alongside other System Sensor notification and detection products, including the 100 Series Plug-In Smoke Detectors and Bases referenced in the same product family documentation. Because it runs on the same NAC voltage as strobes and horn-strobes common to commercial fire alarm systems, it integrates into mixed notification circuits where a distinct bell tone is required in specific zones — mechanical rooms, kitchens, or areas where ambient noise demands a different acoustic signature than horns or speakers. Circuit designers should account for the bell's current draw against attached detector and end-of-line (EOL) relay current draw when calculating total NAC loading, and note that the rated draw does not include reverse polarity current draw from attached detectors — a detail that matters when a circuit runs in reverse polarity supervision mode common on many conventional panels.
What's in the Box
Package contents documented for the SSM24-6 reference compatibility with 100 Series Plug-In Smoke Detectors and Bases; consult the wiring diagram supplied with the unit for exact mounting hardware included.
Frequently Asked Questions
Q: What voltage does the SSM24-6 run on?
A: The SSM24-6 is rated for 24VDC, matching standard notification appliance circuits on commercial fire alarm control panels.
Q: What size is the SSM24-6 bell?
A: It's a 6-inch signal bell, sized for a lower-pitched, longer-carrying tone than compact 4-inch bells.
Q: Can the SSM24-6 be installed outdoors or in unconditioned spaces?
A: It's rated for an operating temperature range of –31°F to 140°F, which covers most unconditioned mechanical rooms, stairwells, and covered outdoor locations.
Q: What mounting options does the SSM24-6 support?
A: Wall, ceiling, or rack mounting, depending on the installation location and existing box placement.
Q: What's the warranty on the SSM24-6?
A: The SSM24-6 carries a 3-year warranty.
Q: Does the SSM24-6 work with other System Sensor detection devices on the same circuit?
A: Yes — it's designed to operate on the same 24VDC notification circuits as System Sensor's 100 Series Plug-In Smoke Detectors and Bases.
The SSM24-6 is a 6-inch, 24VDC signal bell, and the spec that matters most here is the voltage match to standard notification appliance circuits — no separate power supply, no conversion hardware, just a direct tie-in to the NAC output most commercial panels already provide.
Technical Highlights:
- 24VDC NAC compatibility: drops onto existing notification circuits without additional power conditioning.
- 6-inch gong: larger than compact 4-inch bells, producing a lower, longer-carrying tone suited to bigger open floor areas.
- Operating range –31°F to 140°F: covers unconditioned mechanical spaces and covered outdoor mounting locations most indoor-rated appliances can't handle.
Deployment Considerations:
- When sizing NAC circuit load, account for current draw from attached detectors or the EOL relay — the bell's rated draw does not include reverse polarity current draw from attached detectors, which trips up load calculations on reverse-polarity supervised circuits.
- Mounting is flexible (wall, ceiling, or rack), but confirm box placement matches code-required audibility levels for the space before finalizing rough-in.
Specify the SSM24-6 where a zone needs a distinct mechanical bell tone instead of an electronic horn — mechanical rooms, kitchens, and industrial floors with high ambient noise are the classic call for this device over a standard horn-strobe.
