ABB / General Electric THHQB1120 Miniature Circuit Breaker

This bolt-on circuit breaker mounts directly into GE A-Series panelboards and ABB ReliaGear lighting panels. It requires a bolt-on bus connection and will not fit standard residential load centers that utilize plug-in Q-Line breakers.

The addition of the letter "H" indicates a higher interrupting capacity. The THHQB1120 has a 22kAIC rating, while the standard THQB1120 is rated at 10kAIC. You can use the THHQB1120 as a direct, higher-rated replacement for a THQB1120 if your panel requires enhanced fault current protection.

The lugs accommodate 14 to 8 AWG copper (Cu) conductors or 12 to 8 AWG aluminum (Al) conductors. Ensure your wire selection aligns with standard 20-amp ampacity rules and matches the 60 or 75 degree Celsius temperature ratings noted on the breaker faceplate.

Yes. While it carries a maximum voltage limit of 120/240VAC, this 1-pole breaker is frequently used to protect 120-volt branch circuits derived from a 208Y/120V three-phase distribution panel, provided the available fault current remains under 22kA.

It features a bolt-on mounting design. The breaker fastens directly to the busbar with a screw, creating a highly secure connection designed to withstand the vibrations typical in commercial and industrial electrical environments.

Proper torque is critical to prevent arcing or overheating at the terminal lug. Since values depend on the specific wire gauge and material, you must refer to the specification label printed directly on the circuit breaker or the panelboard interior instructions for the exact inch-pound torque requirements.

The "LI" code means the breaker utilizes a thermal-magnetic mechanism providing Long-Time and Instantaneous protection. The thermal component handles gradual overloads, while the magnetic component provides an immediate trip response during a short circuit.

Yes, GE Q-Line miniature circuit breakers, including the THHQB series, are typically HACR rated. This certification means they are approved for use with heating, air conditioning, and refrigeration equipment that requires group motor protection.