Overview
The United Electric Controls B402-120 temperature switch delivers robust industrial temperature monitoring and control for critical process applications. As part of the proven 400 Series family, this unit combines dual SPDT relay outputs with a 0-225°F adjustable setpoint range, making it ideal for multi-stage alarm, safety, and emergency shutdown functionality. The electromechanical design operates independently of networked control systems, providing failsafe protection free from communication errors or cyber vulnerabilities.
Key Features
- Dual SPDT switch outputs for multi-stage alarm and shutdown control
- 0-225°F adjustable setpoint range with 5° scale divisions; maximum operating temperature 275°F
- Rated 15A at 125/250/480VAC resistive loads
- Nickel-plated brass immersion stem with internal reference dial adjustment
- Weather-tight Lexan enclosure rated for ordinary industrial locations
- Global agency certifications and worldwide design standards compliance
- Failsafe electromechanical operation—no dependency on external control systems
Technical Specifications
- Temperature Range: 0–225°F adjustable setpoint (–17.8–107.2°C); max 275°F
- Electrical Rating: 15A at 125/250/480VAC resistive
- Switch Type: 2 SPDT (dual single-pole double-throw)
- Immersion Stem: Nickel-plated brass, 9/16″ OD × 1-7/8″ below threads
- Adjustment Method: Internal reference dial mechanism
- Scale Division: 5°F increments
- Enclosure: Gasketed Lexan, weather-tight, ordinary location rated
- Vibration Rating: Set point repeatable after 2.5G, 5–500 Hz
- Series: 400 Series
- Weight: 4.0 lbs
Typical Applications
The B402-120 is widely used throughout industrial process control, HVAC systems, and equipment protection:
- Multi-stage temperature alarms and safety shutdown in process industries
- Rotating equipment protection (pumps, compressors, turbines)
- Heat tracing and combustion system monitoring
- Oil, gas, and chemical processing temperature control and alarm
- Machine tool coolant and fluid temperature monitoring
- Any critical process requiring independent, failsafe temperature sensing
Compatibility & Replacements
Compatible With
- Standard 125VAC, 250VAC, and 480VAC control circuits
- Dual-output relay logic for sequential alarm and shutdown sequences
- Industrial motor control centers and switchboards
- Process monitoring and instrumentation systems (standalone operation)
- Thermal protection and emergency shutdown applications
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering. The B402-120 is a full 400 Series unit; cross-compatibility with other series (e.g., C402, F120) depends on electrical voltage class, switch configuration, and mechanical mounting.
Works With
- Standard electromechanical relay and contactor circuits
- Direct wiring to motor starters, solenoids, and alarm devices
- No software integration required—pure hardwired control
- Compatible with existing plant electrical infrastructure rated for 125/250/480VAC switching
