Safety Clearances and Minimum Distances
When installing a circuit breaker, minimum distances (safety clearances) must be maintained between the device and panels, busbars and other protection devices installed nearby. These distances are defined by tests carried out in accordance with UL standards.
If installation is not checked by type tests, it is also necessary to:
use insulated bars for circuit breaker connections.
segregate the busbars using phase barriers.
For PowerPact B-frame devices, terminal shields and interphase barriers are recommended and may be mandatory depending on type of installation.