Overview
The Square D B56 thermal overload heater element is a plug-on thermal unit designed for motor overload protection in industrial and commercial motor control applications. This lot includes 3 individual heater elements, each rated for 12.6–14.3 amperes full load current. The B56 uses a melting alloy sensing method to detect motor overload conditions and provides Class 20 trip protection, tripping in 20 seconds or less under overload.
Key Features
- Class 20 trip rating with standard trip type
- Melting alloy sensing method for accurate thermal detection
- Plug-on installation for quick, easy replacement and maintenance
- Rated up to 600 volts AC for flexibility in control circuits
- Compatible with NEMA sizes 00-7 motor starters and overload relays
- Reliable motor protection in thermal overload relay assemblies
Technical Specifications
| Amperage Range | 12.6–14.3 Amps (Full Load) |
| Voltage Rating | 600 Volts AC (Maximum) |
| Trip Class | Class 20 (trips in ≤20 seconds at 600% overload) |
| Sensing Method | Melting Alloy |
| Mounting Type | Plug-On |
| Trip Type | Standard |
| Compatible NEMA Sizes | 00, 0, 1, 2, 3, 4, 5, 6, 7 |
| Series | Square D B Series |
| Manufacturer | Square D (Schneider Electric) |
| Quantity | 3 Heater Elements per Lot |
Typical Applications
The Square D B56 is widely used in motor protection circuits across manufacturing, HVAC, pumping, and material handling applications. It provides overload protection for three-phase and single-phase AC motors in the 12.6–14.3 ampere range. Common applications include:
- Thermal overload relay assemblies in magnetic motor starters
- Motor control centers and industrial control panels
- HVAC and refrigeration compressor motor protection
- Pump and fan motor protection circuits
- General-purpose industrial machinery motor control
Compatibility & Replacements
Compatible With
- Square D thermal overload relays (B series)
- Square D magnetic motor starters
- Square D motor control centers
- NEMA-rated motor starter assemblies (sizes 00–7)
- Standard three-phase and single-phase AC motor circuits
Replaces / Drop-In Replacement For
The Square D B56 heater element directly replaces original B56 thermal units in Square D thermal overload relay assemblies. Verify amperage rating (12.6–14.3A) and NEMA size compatibility with your specific motor starter before ordering.
Works With
- Square D thermal overload relay assemblies
- IEC and NEMA-compliant motor control systems
- 600V AC distribution systems
- Motor protective relay circuits
- Industrial automation and control applications
