Overview
The Square D A4.79 overload heater is a type A thermal unit designed for motor control and overload protection applications. This heater element provides reliable trip protection in thermal overload relays, magnetic motor starters, and motor control equipment. Built to Square D specifications, the A4.79 delivers consistent melting-alloy sensing technology for predictable motor protection.
Key Features
- Full-load ampere rating: 3.41–3.79 amps (1 thermal unit)
- Type A series thermal unit for Square D starters and relays
- Melting-alloy sensing technology for reliable trip action
- Plug-in mounting for easy installation
- Standard trip class 20 behavior
- Authentic Square D component manufactured to OEM specifications
Technical Specifications
- Model: A4.79
- Series: A Series (Type A)
- Current Rating: 3.41–3.79 amps
- Sensing Method: Melting Alloy
- Trip Type: Standard Trip
- Trip Class: 20
- Mounting: Plug-in
- Units: 1 Thermal Unit
Typical Applications
The Square D A4.79 heater element is commonly used in:
- Thermal overload relays paired with AC/DC magnetic starters
- Manual starter overload protection circuits
- Separately mounted overload relay assemblies
- Motor protection in industrial control panels
- Equipment requiring overload trip ratings between 3.41 and 3.79 amps
Compatibility & Replacements
Compatible With
- Square D thermal overload relays (A series)
- Square D magnetic motor starters
- Square D NEMA and definite-purpose starters
- AC/DC motor control applications
- Manual starter overload protection systems
Replaces / Drop-In Replacement For
Verify compatibility with your system integrator before ordering. The A4.79 is a standard A-series type A thermal unit; consult the motor starter nameplate or heater selection table to confirm correct ampere rating for your application.
Works With
- Square D Class 8502 and similar magnetic starters
- Square D type A thermal relay assemblies
- Industrial control systems requiring melting-alloy thermal protection
- OEM motor starter thermal unit slots rated for A-series components
