Built for commercial and industrial applications, the Siemens HJXD63B300 is a 3-pole, 300A molded case circuit breaker from the Sentron series. It features a durable JD-frame construction and provides reliable thermal-magnetic protection with adjustable magnetic trip settings. This bolt-on MCCB is engineered to mount into Siemens P4 and P5 panelboards, as well as compatible switchboards. Lugs are not included. It delivers a high interrupting capacity of 65kAIC at 480V for demanding loads.
HACR Rated, Reverse Feed, High Interrupting Capacity, Non-Interchangeable Trip
Product FAQs
8 answers
What panelboards are compatible with the Siemens HJXD63B300?
This JD-frame breaker is designed for installation in Siemens P4 and P5 panelboards, as well as compatible Siemens switchboards.
What does the H in the HJXD63B300 catalog number signify?
The H indicates a high-interrupting capacity. Compared to standard JXD6 breakers, this model offers increased short-circuit ratings, including 65kAIC at 480V and 35kAIC at 600V.
What does the X in the HJXD63B300 part number mean?
The X designates that this circuit breaker is built with a non-interchangeable trip unit.
Is the trip unit on the HJXD63B300 adjustable?
Yes. While the long-time thermal protection is fixed, the instantaneous magnetic trip function is adjustable to help coordinate with other downstream protection devices.
What lug kits are compatible with this JD-frame breaker?
This Sentron breaker accepts standard JD-frame lug kits, such as the TA2J6500 for dual-rated aluminum connections or the TC2J6500 for copper connections. Both kits typically accept wire sizes from 3/0 AWG to 500 kcmil.
Can the HJXD63B300 be used in DC voltage systems?
Yes, this thermal-magnetic breaker is UL rated for ungrounded DC systems up to 500VDC, providing a 25kAIC interrupting rating for those applications.
Is this Sentron circuit breaker suitable for reverse feed applications?
Yes, because it features a non-interchangeable trip unit, the HJXD6 series is UL listed for reverse feed installations.
What is the maximum frame rating for Sentron JD-frame breakers?
Although this specific breaker is factory-calibrated for 300A, the overall JD frame size supports continuous current ratings ranging from 200A up to a maximum of 400A.
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