5A USONIC Overload Switch Code: 03909541

A 5A Usonic (or similar) overload switch is a compact thermal circuit breaker designed to protect electrical equipment from excessive current. It automatically cuts power when the current exceeds 5 Amps, preventing damage or fire, and features a manual push-button reset.

Key Specifications & Features

• Current Rating:5A (Disconnects when the circuit draws more than 5 Amps)
• Voltage Rating:Compatible with 120VAC up to 250VAC (50/60Hz)
• Operation Type:Thermal
• Reset Mechanism:Manual push-button (resets the circuit once the fault is cleared and the unit cools down)
• Electrical Life:Up to 10,000 operations
• Contact Resistance:≤ 40 mΩ

Common Applications

These switches are universally used to safeguard power strips, UPS systems, power adapters, and small appliances against sudden surges or equipment faults.

How It Works

Inside the switch is a bimetallic strip. When a current higher than 5 Amps flows through it, the excess heat causes the strip to bend. This physical movement trips the internal contacts and disconnects the circuit. Once the switch cools, pressing the reset button forces the contacts back together, reconnecting the power.