ABB XT4HU3150BFF000XXX Molded Case Circuit Breaker

Its rated current is 150A; 250A is the frame current. Use 150A for current-rating selection, and treat the 250A frame rating as a separate characteristic rather than the breaker's operating rating.

The interrupting rating is 65kA at 480VAC. Compare that rating with the available fault current at the installation point; the available fault current must not exceed the interrupting rating.

Use the 600VAC rating to evaluate the circuit's operating voltage. Evaluate interrupting capacity at the applicable voltage as well; this breaker's 65kA interrupting rating applies at 480VAC.

LI means long-time and instantaneous protection. The thermal element responds to sustained overloads, while the magnetic element responds rapidly to high fault current, so selection must account for both load behavior and fault protection.

Both the thermal and magnetic trip elements are adjustable. This lets you tailor overload and instantaneous response to the circuit's protection requirements while keeping conductor protection and coordination in view.

This is a three-pole breaker for three-phase circuits. Use those characteristics when selecting a breaker to interrupt and protect the three phase conductors.

The terminal connection is bolt type. Plan the conductor termination work around bolted electrical connections rather than treating the terminals as wire-clamping connections.

The breaker measures 6.30 in high, 4.13 in wide, and 3.25 in deep, and weighs 5.51 lb. Use these dimensions and weight for layout and handling planning, with working space for the bolted terminations.