ABB / General Electric THHQB2120 Miniature Circuit Breaker

This bolt-on miniature circuit breaker is designed specifically for installation in GE A-Series panelboards and GE AQ lighting panels.

No. The THHQB2120 is a bolt-on breaker intended for commercial A-Series and AQ panelboards. Standard residential GE load centers typically require plug-on breakers like the THQL or THQP series.

The difference lies in the maximum interrupting capacity. The standard THQB2120 is rated for 10 kAIC, whereas the THHQB2120 features a higher short-circuit interrupting rating of 22 kAIC at 240V. Both share the same physical frame and bolt-on mounting style.

Yes, the integrated box lugs are rated for both copper and aluminum conductors. The acceptable wire range is 14 to 8 AWG for copper and 12 to 8 AWG for aluminum.

According to manufacturer specifications, the box lugs should be torqued to 35 in-lb for 10 AWG wire and 40 in-lb for 8 AWG wire. Always verify exact torque values on the physical breaker label before finalizing the installation.

ABB acquired GE Industrial Solutions, the division responsible for Q-Line circuit breakers, in 2018. As a result, the THHQB2120 may arrive with ABB or GE branding, but it is the exact same component and remains fully backward compatible with existing GE electrical panels.

This 2-pole breaker features an internal common trip. If an overcurrent or short circuit occurs on one leg, the internal mechanism ensures both poles trip simultaneously, safely removing power from the entire 240V circuit.

The LI trip function code indicates that this thermal magnetic breaker provides both Long-Time and Instantaneous protection. The long-time function protects against sustained overloads, while the instantaneous function reacts immediately to high-level short circuits.