Overview
The Square D B6.90 is a thermal overload relay heater element designed for use in industrial and commercial motor control applications. This melting alloy heater unit provides reliable overload protection and is rated for 4.48 to 5.68 A full load amperage with Class 20, standard trip operation. The plug-in mounting design ensures fast installation and replacement in Square D thermal overload relay assemblies.
Key Features
- Melting alloy sensing technology for consistent, repeatable overload detection
- Plug-in mounting for quick installation and replacement
- Class 20 standard trip rating
- Compatible with Square D magnetic motor starters and motor control systems
- Rated for 600 V AC applications
- Type B thermal element
Technical Specifications
| Part Number | B6.90 |
| Manufacturer | Square D |
| Product Type | Thermal Overload Relay Heater Element |
| Sensing Method | Melting Alloy |
| Trip Classification | Standard Trip |
| Class Rating | Class 20 |
| Full Load Amperage Range | 4.48–5.68 A |
| Voltage Rating | 600 V AC |
| Mounting Style | Plug-In |
| Element Type | Type B |
Typical Applications
The Square D B6.90 heater element is ideal for:
- Motor protection in industrial pump and fan applications
- Machine tool motor starters and control circuits
- HVAC system motor overload protection
- General-purpose motor control and motor starter assemblies
- Replacement of worn or damaged heater elements in existing Square D overload relays
Compatibility & Replacements
Compatible With
- Square D Class 8501 magnetic motor starters
- Square D thermal overload relay assemblies (Type B)
- Square D motor control centers (MCC)
- Square D direct-on-line (DOL) motor starting systems
- Standard 600 V AC industrial motor control circuits
Replaces / Drop-In Replacement For
The Square D B6.90 serves as a direct replacement for heater elements in Square D Class 8501 and other Square D thermal overload relay models requiring Type B, 4.48–5.68 A melting alloy elements. Verify your existing heater element part number and amperage range before ordering.
Works With
- Square D overload relay platforms and assemblies
- Manual motor starters with overload protection
- Magnetic motor control systems
- Industrial control circuits rated 600 V AC
- Motor protection and alarm circuits
