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Kidde | 302 Series All-Weather Rate Compensation Heat Detector - 135F, 1/2" NPT Box Mount, FM & UL | 302-ET-135

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SKU:
KD-302-ET-135

The Kidde 302-ET-135 is an all-weather rate compensation heat detector rated at 135F (57.2C), built for moisture-proof and dust-proof installations where conventional detectors fall short. Its 1/2" NPT threaded base mounts directly to any standard outlet box or threaded hub cover - no special back box required for indoor work. For outdoor or watertight applications, pair it with a STONCO27 or equivalent weatherproof box.

Built for the commercial fire installer

Rate compensation technology offsets thermal lag, giving the 302-ET faster and more reliable response than conventional fixed-temperature detectors in both slow-building and fast-developing fire conditions. The detector is hermetically sealed, shock and corrosion resistant, tamperproof, and self-restoring - it resets automatically when ambient temperature drops below the rated threshold. FM and UL listed with MEA acceptance.

Key features

  • Rate compensation offsets thermal lag for reliable detection across both slow and rapid temperature rises
  • Self-restoring operation - no manual reset required after activation
  • Hermetically sealed, all-weather construction for moisture-proof, dust-proof, and corrosion-resistant performance
  • 1/2" NPT box mount threads into any standard outlet box or threaded hub cover
  • FM, UL, and MEA listed for conventional fire alarm initiating circuits
  • -40F to 100F ambient operating range covers cold-storage, loading dock, and outdoor applications

System requirements

Wires into any conventional fire alarm control panel as a normally-open initiating device with end-of-line resistor supervision. Two-wire connection (black and white leads). For outdoor or watertight installations, mount in a STONCO27 or equivalent weatherproof junction box.

Brand:
Kidde
Form factor:
All-weather heat detector, 1/2" NPT vertical box mount
Temperature rating:
135°F (57.2°C) fixed temperature
Detection method:
Rate compensation (offsets thermal lag)
Circuit type:
Normally-open, closes on activation
Power input:
6-125 VAC (5A) / 6-25 VDC (1A) / 125 VDC (0.5A)
Operating temp:
-40°F to 100°F (-40°C to 38°C) ambient
Mounting:
1/2" NPT threaded bushing, vertical mount to outlet box or hub cover
Tube length:
3" (76.2 mm)
Tube diameter:
0.5" (12.7 mm)
Hex base:
1" (25.4 mm) plastic
Construction:
Hermetically sealed, shock and corrosion resistant, tamperproof
Reset:
Self-restoring (automatic)
UL vertical spacing:
50' x 50' (15.2 x 15.2 m)
UL horizontal spacing:
40' x 40' (12.2 x 12.2 m)
FM spacing:
30' x 30' (9.1 x 9.1 m)
Compliance:
FM, UL, MEA
Required accessory:
STONCO27 or equivalent weatherproof box (for watertight installations)
Ship weight:
0.2 lb (0.09 kg)
Does this detector require a manual reset after activation?
No. The 302-ET-135 is self-restoring. When surrounding air temperature drops below the 135°F rated threshold, the outer shell contracts and the contacts open automatically - no truck roll to reset.
Can I use the 302-ET-135 outdoors?
Yes. The 302-ET is hermetically sealed and all-weather rated. For outdoor or watertight installations, mount it in a STONCO27 or equivalent weatherproof junction box.
What type of fire alarm panel is this compatible with?
Any conventional fire alarm control panel that accepts normally-open initiating devices. Wires in on a standard two-wire supervised circuit with an end-of-line resistor.
What is rate compensation and why does it matter?
Rate compensation offsets thermal lag caused by the housing absorbing heat before the sensor responds. The 302-ET activates closer to its rated temperature whether fire builds slowly or fast, cutting both false alarms and missed detections.
What mounting box does the 302-ET-135 require?
The 1/2" NPT threaded bushing attaches to any standard outlet box or threaded hub cover. For watertight or outdoor installations, use a STONCO27 or equivalent weatherproof box.
What is the maximum ceiling temperature for normal operation?
100°F (38°C). Install away from direct sunlight, heaters, heat ducts, and paint booths that use heat to cure. The aluminum tube acts as a heat collector when exposed to radiant heat sources.

Spec Sheet