Siemens HJD63B400 Molded Case Circuit Breaker

Yes. Siemens retained the Sentron series dimensions, footprint, and catalog numbering after acquiring I-T-E. A current Siemens HJD63B400 is a direct, drop-in replacement for an older I-T-E breaker sharing the identical catalog number.

The "H" in the catalog number designates this as the high-interrupting capacity version. While both models share the exact same physical JD frame footprint, the HJD63B400 is built to safely interrupt significantly higher short-circuit fault currents (up to 65kA at 480V AC) than the standard JD6 version.

Yes. In the Siemens Sentron catalog system, the "B" suffix designates a complete circuit breaker (including both the frame and trip unit) that ships unassembled with lugs. The standard line and load side lugs are included in the packaging but must be bolted to the breaker terminals in the field.

While the thermal-magnetic trip unit provides a fixed thermal response for continuous overload protection, it features an adjustable instantaneous (magnetic) dial. This allows electricians to fine-tune the short-circuit trip threshold to properly accommodate motor inrush currents and cleanly coordinate with downstream protective devices.

No. Standard Siemens HJD6 breakers feature line and load markings and are not UL Listed for reverse-feed applications. If your installation requires backfeeding, you must specifically source the HJXD63B400 version, which is tested and listed for reverse-fed configurations.

As a unit-mount device, this breaker does not simply snap onto a standardized panelboard bus structure. Instead, it bolts individually to the backpan or chassis of compatible enclosures, such as Siemens P4 and P5 panels or SB switchboards. It is then wired to the power system using cables or specialized copper mounting strap kits.