The Intermatic K4221C is a 120V photo control built for professional electricians and contractors who need reliable dusk-to-dawn switching on outdoor lighting installations. Whether you're wiring up parking lot fixtures, security lighting, or residential exterior luminaires, the K4221C delivers consistent, automatic on/off control without manual intervention. Its mechanical bimetal switch paired with a Cadmium Sulfide (CdS) photocell provides proven, field-tested performance, while the built-in delay feature eliminates nuisance tripping caused by passing headlights or brief cloud cover — keeping your installations running exactly as intended.

Specifications

Input Voltage 120 VAC, 50/60 Hz
Mounting Style Stem and Swivel Mount
Stem Size 1/2" diameter, 1/2"-14 NPSM thread
Switch Type Mechanical Bimetal, SPST
Photocell Type Cadmium Sulfide (CdS), Side-mounted sensor
Activation (Turn ON) 1 to 5 fc
Activation (Turn OFF) 3 to 15 fc
Sensor Time Delay 30 sec to 90 sec
Fail Mode ON
Compatible Lamp Types Fluorescent, HID, Incandescent
Incandescent / Tungsten Load 15 A / 1800 W
Magnetic Ballast Load 8.3 A / 1000 VA
Housing Material Polycarbonate (UV resistant)
Colour Grey
Usage Environment Outdoor
Operating Temperature -40°C to 70°C (-40°F to 158°F)
Wire Leads #18 AWG, 6"
Certifications cULus, cCSAus, Green Energy, Title 20
Country of Origin Mexico
Warranty 2-Year Limited
Dimensions (H × W × D) 5" × 1.563" × 1.563" (127 × 39.7 × 39.7 mm)