Overview
The Intermatic K4121 is a thermal-type stem-mounted photocontrol designed to manage tungsten lighting loads automatically. With a tungsten rating of 1800W and ballast VA of 1000 at 120VAC with 50/60Hz operation, this unit provides reliable dusk-to-dawn control for outdoor and commercial lighting applications. Thermal-type photo controls provide dusk-to-dawn lighting control and delay action, eliminating loads switching off due to car headlights and lightning.
Key Features
- Thermal-Type Photocell: Cadmium sulfide photocell with sonic-welded polycarbonate case and lens to seal out moisture
- Temperature Compensated: Dual temperature compensating bimetal and composite resistor for reliable long life operation over ambient temperature extremes
- Compact Stem Mount: 1/2-inch threaded stem design suitable for standard outlet boxes, post lamps, and wall packs
- Low Power Consumption: Power consumption averages under 1 Watt
- Regulatory Compliance: California Title 24 compliant, UL Listed
Technical Specifications
Electrical Ratings:
- Input Voltage: 120VAC, 50/60Hz
- Tungsten Load: 1800W maximum
- Tungsten Current: 15A
- Ballast VA: 1000VA
- Ballast Current: 8.3A
- Contact Type: SPST (Single Pole Single Throw)
Environmental & Physical:
- Operating Temperature Range: -40°F to 158°F (-40°C to 70°C)
- Sensor Type: Cadmium sulfide, thermal compensated
- Light Activation: 1-5 foot candles ON; 3-15 foot candles OFF
- Delay Action: 30 to 90 seconds
- Wire Gauge: 18 AWG leads
- Housing Material: Polycarbonate
- Mounting: 1/2-inch threaded stem mount
- Dimensions: 1 9/16 inches square, 3 inches long
- Color: Gray
Typical Applications
- Commercial outdoor lighting control
- Post-mounted and wall-pack fixture controls
- Street and parking lot lighting automation
- Sign lighting and security lighting
- Retrofit tungsten ballast control systems
Compatibility & Replacements
Compatible With
- Standard 1/2-inch NPT threaded stem outlet boxes
- Post lamps and wall packs rated for 1800W tungsten loads
- 120VAC 50/60Hz electrical systems
- Tungsten incandescent lamp assemblies
Replaces / Drop-In Replacement For
- K4121C: Updated variant of the K4121 with same electrical ratings and footprint
- Legacy Intermatic K4100 series 120V single-voltage models
Works With
- Tungsten incandescent lamps (standard A-type and PAR-type bulbs)
- Standard electrical wiring and conduit systems
- Outdoor and indoor lighting fixtures with 1/2-inch stem mounting provisions
