Built for commercial applications, the Siemens JJ63B400 is a 3-pole, 400A molded case circuit breaker. It operates at up to 600VAC, delivering robust thermal-magnetic protection. This bolt-on unit installs into Siemens P4 and P5 panelboards or switchboards. As a legacy component, it serves as an exact replacement for older setups and is succeeded by the JXD63B400. Rated at 65kAIC at 240VAC, it features fixed thermal and adjustable magnetic trip settings, plus a HACR rating for HVAC equipment.
Which panelboards are compatible with the Siemens JJ63B400?
This bolt-on J-frame circuit breaker is designed for installation in Siemens P4 and P5 panelboards, as well as compatible Siemens switchboards and older ITE enclosures.
Is the Siemens JJ63B400 still manufactured, or is there a direct replacement?
The JJ63B400 is a legacy, discontinued component. For new installations or direct replacements, the Siemens JD63B400 (interchangeable trip) or JXD63B400 (non-interchangeable trip) are the current succeeding models.
Which lug kit is required for the JJ63B400 breaker?
The standard lug kit for this 400A J-frame breaker is the TA2J6500, which accepts aluminum or copper wire ranging from 3/0 AWG to 500 kcmil.
Is the JJ63B400 suitable for use with heating and air conditioning equipment?
Yes, this breaker is HACR rated, making it suitable for use with heating, air conditioning, and refrigeration equipment that requires this specific certification.
Does the JJ63B400 feature an interchangeable trip unit?
Yes, the standard JJ63B400 features an interchangeable thermal-magnetic trip unit. This allows the trip unit to be replaced or upgraded without removing the entire breaker frame.
Can the Siemens JJ63B400 be reverse fed?
Yes, standard JJ63B400 breakers can be reverse fed. However, breakers specifically marked with LINE and LOAD designations on the casing must be wired directionally and cannot be reverse fed per UL 489 standards.
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