ABB / General Electric TB43125 Molded Case Circuit Breaker

This bolt-on breaker is designed specifically for GE Tri-Break panelboards, GE switchboards, and compatible motor control centers (MCCs). It is not intended for standard residential load centers or A-Series lighting panels.

The factory lugs accept either a single aluminum or copper conductor ranging from 6 AWG to 600 kcmil, or dual conductors ranging from 2/0 AWG to 250 kcmil. Ensure proper torque specifications are followed during installation to prevent thermal issues.

While the thermal overload protection is fixed at 125 amps, the magnetic trip is adjustable. This allows licensed electricians to dial in the instantaneous short-circuit response threshold to coordinate with other protective devices in the system and prevent nuisance tripping during motor inrush currents.

ABB acquired GE Industrial Solutions in 2018. As a result, newly manufactured Tri-Break series breakers like the TB43125 may feature ABB branding, labels, or packaging. The physical dimensions, mounting hardware, and electrical specifications remain identical.

The 200,000 Ampere Interrupting Capacity (AIC) indicates the maximum fault current this breaker can safely clear without sustaining catastrophic damage. The Tri-Break design achieves this exceptionally high rating across 240V, 480V, and 600V AC systems without requiring external current-limiting fuses.

Installation must be performed by a qualified electrician with the panelboard or switchboard completely de-energized. Proper PPE must be worn in accordance with NFPA 70E guidelines, and all bolted bus connections must be torqued to the manufacturer specifications to ensure a low-resistance connection.