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Siemens / ITE CJ3B400 Molded Case Circuit Breaker
- 400A
- 3 Pole
- Bolt-On
Siemens / ITE
CJ3B400
Molded Case Circuit Breaker
Brand
Siemens / ITE
SKU
CJ3B400
Quantity
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Siemens / ITE CJ3B400 - 400A 3 Pole Molded Case Circuit Breaker
Re-Certified
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Description
Rated 100 kAIC at 480VAC, this 400A molded case circuit breaker utilizes integrally fused Amp-Trap limiters to isolate severe electrical faults. The CJ3B400 installs into existing ITE and Siemens switchboards or motor control centers, providing a seamless replacement solution for aging infrastructure. By combining fixed thermal and adjustable magnetic trip functions, it ensures precise overcurrent protection for heavy-duty commercial and industrial applications.Specifications
| Brand | Siemens / ITE |
|---|---|
| Part Number | CJ3B400-R |
| Series | CJ |
| Amperage | 400A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 100kA @ 480VAC, 100kA @ 600VAC, 100kA @ 250VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | ITE / Siemens Switchboards, Motor Control Centers, CDP Panelboards |
| Wire Gauge | 250 kcmil - 500 kcmil (Cu), 350 kcmil - 500 kcmil (Al) |
| Max Wire | 500 kcmil |
| Min Wire | 250 kcmil |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Adjustable Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch |
|---|---|
| Accessories | Lugs Not Included |
| Standards | UL 489, NEMA AB 1 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Current Limiting, Integrally Fused, Amp-Trap Limiters |
| Special Features | Current Limiting (Integrally Fused) |
Product FAQs
7 answersWhat types of enclosures or panels are compatible with the CJ3B400 breaker?
The CJ3B400 is a bolt-on molded case circuit breaker designed for use in legacy ITE and Siemens switchboards, motor control centers (MCCs), and CDP panelboards. It mounts directly to the busbar using bolt-on connections.
What makes the CJ3B400 a current-limiting breaker?
The CJ3B400 is a Cordon-style breaker that utilizes integrally fused limiters to achieve its 100kA interrupting capacity. During a severe short circuit, these limiters clear the fault in less than a half-cycle, significantly reducing the let-through energy and protecting downstream equipment.
What are the wire size requirements for the CJ3B400 lugs?
The standard lugs accept copper wire from 250 to 500 kcmil, or aluminum wire from 350 to 500 kcmil. When installing, ensure the conductors are sized appropriately for the 400A continuous rating and that the lugs are torqued to the specifications printed on the breaker faceplate.
How is the trip unit configured on the CJ3B400?
This breaker features a thermal-magnetic trip unit with Long-Time and Instantaneous (LI) functions. The thermal element is fixed for 400A continuous current protection, while the magnetic instantaneous trip is adjustable. This adjustability allows you to fine-tune the short-circuit response to prevent nuisance tripping during motor inrush or high-load startups.
Can the CJ3B400 be used in DC applications?
Yes, in addition to its 600VAC rating, the CJ3B400 is rated for up to 250VDC systems. It maintains a high interrupting capacity of 100kA across all rated voltages, making it suitable for heavy-duty industrial AC and DC environments.
Is the CJ3B400 still actively manufactured?
The CJ3B400 is a legacy ITE and Siemens breaker that is no longer in active production. It is primarily sourced as a direct replacement part to maintain existing CDP panelboards and older Siemens switchboards without requiring a full system retrofit.
What maintenance is recommended for legacy ITE CJ-frame breakers?
Routine maintenance for legacy breakers like the CJ3B400 should include visual inspections for signs of overheating or case cracking, verifying that lug torque meets manufacturer specifications, and periodically exercising the breaker mechanism to ensure the contacts open and close smoothly.
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