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Kidde Commercial
Kidde | SuperDuct Four-Wire Photoelectric Duct Smoke Detector Sensor with RJ45 | SD-SJ

SuperDuct Four-Wire Photoelectric Duct Smoke Detector Sensor with RJ45

SKU KD-SD-SJ

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The Kidde SuperDuct SD-SJ is the sensor assembly for Kidde's four-wire SuperDuct duct smoke detection system. This is the sensor-only unit - it connects to a separate SD-CJ controller via standard RJ45 cable, making it the right choice when you need to add a second detection point to an existing controller or mount the sensor remotely from the controller (up to 100 feet away).

Built for the commercial installer

SuperDuct sensors use photoelectric detection with Kidde's patented differential sensing. Every eight minutes the sensor checks its environment for dirt, humidity, and other conditions that cause sensitivity drift in conventional duct detectors, then auto-compensates. The result: fewer false alarms and fewer service callbacks over the life of the system. UL, ULC, CSFM, FM, and MEA listed.

Key features

Less than 2" deep - fits tight above-ceiling spaces where deeper units won't
Patented differential sensing auto-compensates for environmental drift every 8 minutes, reducing nuisance alarms
RJ45 modular interconnection to the SD-CJ controller - no terminal wiring at the sensor
100 to 4,000 ft/min air velocity rating covers a wide range of HVAC duct configurations
Dedicated dirty/trouble LED visible through the clear cover without opening the unit
Magnet-activated test/dirty/reset - no need to remove the cover for field testing
Sampling tubes install from front or back of housing, rotatable in 45-degree increments for flexible mounting

System requirements

The SD-SJ sensor requires an SD-CJ controller (sold separately). One controller supports up to two sensors. The controller provides 24 VAC/VDC, 120 VAC, or 230 VAC power and houses the alarm, trouble, and auxiliary relay contacts. Connect sensor to controller with an SD-RJ series wiring harness (5, 10, or 15 ft lengths available) for remote installation, or mount in tandem using the included integral cable. Air sampling tubes (SD-T series, 8" to 120") are ordered separately.

Specifications

SKU	KD-SD-SJ
Brand	Kidde Commercial
Form factor	Duct smoke detector sensor assembly (sensor only, requires SD-CJ controller)
Detection method	Photoelectric with patented differential sensing
Interconnection	RJ45 modular to SD-CJ controller (CMP cable)
Air velocity rating	100 to 4,000 ft/min
Air pressure differential	0.005 to 1.00 inches of water
Sensitivity	0.67 to 2.46 %obscuration/ft
Operating temp	-4°F to 158°F (-20°C to 70°C) per UL; -4°F to 120°F per ULC
Operating humidity	10 to 93%, noncondensing
Dimensions	8.70" x 5.45" x 1.90" (22.10 x 13.84 x 4.83 cm)
Depth	Less than 2"
Wiring distance	100 ft max from sensor to controller
Wire size	#14 to #22 AWG
LED indicators	Alarm (red), Trouble (yellow), Dirty (yellow), Power (green)
Reset time	2 seconds max
Power up time	8 seconds max
Alarm test response time	5 to 7 seconds
Ship weight	2.4 lb (1.1 kg)
Compliance	UL, ULC, CSFM, FM, MEA

Documents and resources

Spec SheetPDF

FAQs

Does the SD-SJ include a controller?

No. The SD-SJ is the sensor assembly only. It requires a separate SD-CJ controller for power and relay contacts. One SD-CJ controller supports up to two SD-SJ sensors.

How far can the sensor be mounted from the controller?

Up to 100 feet. Use an SD-RJ series RJ45 wiring harness (available in 5, 10, and 15 ft lengths) for remote installation. The sensor can also mount in tandem directly on the controller using the included integral cable.

What air sampling tubes work with this sensor?

The SD-T series sampling tubes, available in lengths from 8" (SD-T8) to 120" (SD-T120). Tubes install from the front or back of the housing and rotate in 45-degree increments for flexible duct mounting. Sampling tubes are ordered separately.

How does the patented differential sensing reduce false alarms?

Every eight minutes the sensor checks for dirt, humidity, and conditions that drift conventional detectors. It auto-adjusts sensitivity to compensate, eliminating gradual drift that triggers nuisance alarms.

Can the sensor be tested without opening the cover?

Yes. Use the magnet-activated test/dirty/reset switch accessible from outside the housing. You can also test remotely with an SD-TRM4 (magnetic) or SD-TRK4 (keyed) remote test/reset station wired to the controller.

Is this suitable for high-humidity duct environments?

Rated 10-93% relative humidity (noncondensing). For condensation-prone environments, add the SD-PH Protective Housing to insulate the detector and circulate duct air, preventing moisture buildup.