SIEMENS
SIEMENS FXD63B250 Molded Case Circuit Breaker 250A 3 Pole
Molded-case circuit breaker rated 250 A with a 22 kA interrupting capacity at 600 V AC and 500 V DC, three-pole thermal-magnetic trip
- 250 A rated current for high-capacity three-phase circuits
- 600 V AC and 500 V DC voltage ratings suit mixed-power systems
- 22 kA interrupting rating at 600 V AC handles large fault currents
- Thermal-magnetic trip with fixed 250 A instantaneous setting provides reliable overload and short-circuit protection
- Free-standing mount with lug terminals simplifies installation in SB switchboards and Sentron panelboards
Industrial circuit protection for 250
The SIEMENS FXD63B250 is a molded case circuit breaker rated for 250 A continuous current on three poles. It uses thermal-magnetic trip units with fixed instantaneous settings and a high amp trip point of 250 A. The breaker fits Sentron panelboards and SB switchboards without lugs using terminal connection lugs and free-standing mounting. It is built for commercial and industrial power distribution where standard interruption is required.
Interruption capacity limited to 22 kA at 600 V AC
The breaker carries a maximum AIR rating of 22 kA at 600 V AC, which defines the highest prospective fault current it can safely interrupt on three-phase AC supplies. For DC circuits the rating is 500 V DC with the same frame. Installations with available fault current above 22 kA at 600 V AC need a higher-rated device. The fixed instantaneous trip cannot be adjusted to coordinate with downstream breakers beyond the published curve.
Fixed thermal-magnetic trip at 250 A decides
Both low and high amp trip settings are fixed at 250 A, so the breaker cannot be field-adjusted for different load profiles or selective coordination schemes. Choose this model only when the design calls for a 250 A frame with non-adjustable thermal-magnetic protection on three phases. Buyers who need adjustable trip settings or a different frame size must select another breaker.
Highlights
- 250 A rated current for high-capacity three-phase circuits
- 600 V AC and 500 V DC voltage ratings suit mixed-power systems
- 22 kA interrupting rating at 600 V AC handles large fault currents
- Thermal-magnetic trip with fixed 250 A instantaneous setting provides reliable overload and short-circuit protection
- Free-standing mount with lug terminals simplifies installation in SB switchboards and Sentron panelboards
Specifications
| Brand | SIEMENS |
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Questions about this item
Should I choose the 250 A frame size or a different ampere rating for my panel?
This breaker has a fixed 250 A frame and identical high and low trip settings of 250 A, so it only fits applications that require that exact rating.
What does the 22 kA rating at 600 V AC mean for my installation?
It is the maximum interrupting capacity — the breaker can safely clear a fault current up to 22 kA on a 600 V AC system without damage.
Does the thermal-magnetic trip unit work on both AC and DC circuits?
Yes, the thermal-magnetic trip operates at 600 V AC and 500 V DC, and the breaker carries a 22 kA AIR rating at 600 V AC.
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