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

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

SKU KD-302-ET-135

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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.

Specifications

SKUKD-302-ET-135
BrandKidde Commercial
Form factorAll-weather heat detector, 1/2" NPT vertical box mount
Temperature rating135°F (57.2°C) fixed temperature
Detection methodRate compensation (offsets thermal lag)
Circuit typeNormally-open, closes on activation
Power input6-125 VAC (5A) / 6-25 VDC (1A) / 125 VDC (0.5A)
Operating temp-40°F to 100°F (-40°C to 38°C) ambient
Mounting1/2" NPT threaded bushing, vertical mount to outlet box or hub cover
Tube length3" (76.2 mm)
Tube diameter0.5" (12.7 mm)
Hex base1" (25.4 mm) plastic
ConstructionHermetically sealed, shock and corrosion resistant, tamperproof
ResetSelf-restoring (automatic)
UL vertical spacing50' x 50' (15.2 x 15.2 m)
UL horizontal spacing40' x 40' (12.2 x 12.2 m)
FM spacing30' x 30' (9.1 x 9.1 m)
ComplianceFM, UL, MEA
Required accessorySTONCO27 or equivalent weatherproof box (for watertight installations)
Ship weight0.2 lb (0.09 kg)

Documents and resources

FAQs

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.
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