Siemens HJXD63B400H Molded Case Circuit Breaker

The "H" suffix indicates that this circuit breaker is 100% rated. While standard breakers are typically rated for 80% continuous load, 100% rated breakers can carry their full 400A nameplate current continuously when installed in an appropriately sized and ventilated enclosure.

No. The "B" in the catalog number indicates that this breaker is supplied as the breaker body only, without lugs. You must order the required line and load lugs separately, such as the TA2J6500 for aluminum or copper wire, or the TC2J6500 for copper wire only.

If you install the standard Siemens TA2J6500 aluminum lugs, they accept copper wire sizes from 3/0 AWG to 500 kcmil, and aluminum wire sizes from 4/0 AWG to 500 kcmil.

No. The HJXD6 series features a non-interchangeable thermal-magnetic trip unit, meaning the 400A rating is fixed and cannot be modified in the field. If your application requires an interchangeable trip unit, you must use the HJD6 frame instead of the HJXD6.

The "H" at the beginning of the HJXD63B400H denotes a high interrupting capacity (65kAIC at 480V), and the "H" suffix means it is 100% rated for continuous duty. A standard JXD63B400 has a lower short-circuit interrupting rating and is only rated for 80% continuous load.

Yes. This thermal-magnetic molded case circuit breaker is UL listed for reverse-feed applications, meaning power can be safely supplied to either the line or load terminals without affecting its protective functions.

While this JD frame breaker is compatible with Siemens P4 and P5 panelboards and switchboards, it does not mount directly to a standard load center bus. It requires a specific main or subfeed breaker mounting kit (strap kit) designed for your exact panel type.