Overview
The Square D B17.5 overload relay is a plug-on thermal heater element designed for motor overload protection in industrial and commercial control systems. This thermal unit is a plug-on, melting alloy type with manual reset, suitable for use in NEMA Size 1 motor starters. It provides reliable overload protection for motors, with a standard trip characteristic and is rated for use up to 600V systems. This lot provides 13 units for inventory, maintenance, or system expansion.
Key Features
- Plug-in mounting standard thermal overload heater unit with melting alloy sensing method and standard trip characteristic
- Manual reset design for NEMA Size 1 motor starters
- Temperature control range of -20 to 140°C for industrial applications
- Part of Square D’s legacy B Series, known for durability and ease of installation
- Class 20 motor tripping classification — standard trip performance
Technical Specifications
- 10 to 14.3 A full load rating (depending on application and ambient conditions)
- 600 V AC maximum voltage rating
- Plug-in mounting style
- Melting alloy sensing method
- Standard trip type (Class 20)
- Manual reset type
- 5 in L x 3.5 in W x 0.8 in H dimensions
Typical Applications
The Square D B17.5 is suitable for use with thermal overload relays, magnetic motor starters and motor controls. Common applications include:
- AC induction motor protection (fractional to 15 HP range)
- Magnetic motor starter assemblies (NEMA sizes 00, 0, 1, 1P, 2)
- Industrial machinery and equipment motor circuits
- HVAC system motor protection
- Pump and fan motor control circuits
Compatibility & Replacements
Compatible With
- Square D NEMA motor starters sizes 00, 0, 1, 1P, and 2
- Square D Class 8536 and 8538 motor starters
- Square D thermal overload relay assemblies
- Manual and magnetic motor starter control circuits
- 600 V AC three-phase and single-phase systems
Replaces / Drop-In Replacement For
- Square D B17.5 original equipment overload heater elements
- Square D B175 (alternate part designation)
- OEM replacements for existing Square D B Series thermal units
Works With
- NEC Article 430 Part C compliant motor protection circuits
- Standard industrial motor control relay logic
- Three-phase and single-phase AC systems
- Manual motor starter assemblies
- Magnetic contactor and overload relay combinations
