Siemens HEB2B125B Molded Case Circuit Breaker

This breaker is engineered specifically for Siemens P1, P2, and P3 panelboards. It requires a bolt-on connection directly to the panel busbar and cannot be used in standard residential load centers that require plug-on breakers.

Both share the same physical footprint and mount in the same panelboards, but the HEB frame offers a higher interrupting rating. The HEB provides up to 100kAIC at 240VAC and 65kAIC at 480VAC, whereas the standard NEB frame has lower short-circuit capacities.

Yes, in addition to standard AC applications, this breaker is rated for DC systems up to 250VDC. It provides a maximum interrupting capacity of 42kAIC at this voltage, making it suitable for specific industrial DC control panels or battery applications.

The factory lugs accept 6 AWG to 3/0 AWG copper or aluminum conductors. Strip the insulation according to the manufacturer guidelines and apply a listed joint compound if using aluminum wire. Always torque the terminal screws to the exact specification printed on the breaker faceplate to prevent thermal issues.

LI stands for Long-Time and Instantaneous trip functions. This is a standard thermal-magnetic configuration where the long-time thermal element protects against sustained overloads, and the instantaneous magnetic element trips immediately during a short circuit.

Always de-energize the panelboard before installing or servicing bolt-on breakers. Verify the power is off using a properly rated voltage tester, and follow all local electrical codes and lockout/tagout procedures before making contact with the busbars.