ABB / General Electric THQL21100ST1 Miniature Circuit Breaker

This 2-pole breaker is designed for GE Q-Line load centers and lighting panels that accept 1-inch plug-in breakers. Always verify that your panel's interior label lists the THQL frame type as an approved device before installation.

The ST1 suffix indicates the breaker includes a factory-installed 120V AC shunt trip. This accessory allows the breaker to be tripped remotely by an external control signal, which is commonly required for emergency power-off applications.

Because ABB acquired GE Industrial Solutions, this exact part number may arrive with either GE or ABB branding on the label. The physical dimensions, electrical ratings, and UL listings remain identical regardless of the logo.

No. The THQL series features a plug-in mounting style. If your panel requires bolt-on connections to the bus bar, you will need the THQB equivalent, such as the THQB21100ST1.

No. THQL breakers require a full 1-inch space per pole, while THQP breakers only require 1/2-inch per pole. They utilize different mounting clips and cannot be substituted for one another, even if the amperage and voltage match.

The factory-installed shunt trip features black wire leads (pigtails) that exit the breaker housing. These leads must be connected to a 120V AC external control circuit, such as an emergency stop button or fire alarm relay, to enable the remote tripping function.

No. This is a standard thermal-magnetic breaker with a shunt trip accessory. It does not provide GFCI or AFCI protection. GE breakers with those features will have suffixes like GFT, GFEP, or AF2.