ABB S4N250BW Molded Case Circuit Breaker
- 250A
- 3 Pole
- Unit Mount
Quantity
ABB S4N250BW - 250A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Designed for commercial and industrial power distribution, the S4N250BW delivers 65kAIC at 240V. This 250-amp, three-pole molded case circuit breaker utilizes an advanced electronic LI trip unit, allowing for adjustable long-time and instantaneous protection settings. It installs into ABB switchboards, motor control centers, and Isomax S4 panelboards. While this specific frame has been succeeded by the Tmax T4 series, it remains a critical component for maintaining existing infrastructure.Specifications
| Brand | ABB |
|---|---|
| Series | Isomax S4 |
| Amperage | 250A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 25kA @ 480VAC, 18kA @ 600VAC |
| Amperage Range | 100-250A |
|---|
| Frame Type | S4 |
|---|---|
| Terminal Type | Lugs |
| For Use With | ABB Switchboards, Motor Control Centers, Isomax S4 Panels |
| Trip Technology | Electronic Trip |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Adjustable |
| Available Options | Shunt Trip, Undervoltage Release, Auxiliary Switch, Bell Alarm, Rotary Handle, Motor Operator |
|---|---|
| Accessories | Lugs Not Included, Mounting Hardware |
| Standards | CSA C22.2, IEC 60947-2, UL 489 |
| Approval | CSA, IEC, UL |
| Temp Rating | 40C |
| Construction Features | Reverse Feed |
Product FAQs
6 answersIs the ABB Isomax S4 series still in active production?
No, the ABB Isomax S4 series is obsolete and has been superseded by the ABB Tmax series. However, exact S4N250BW replacements are often required to maintain existing switchboards and motor control centers without modifying the bus or installing retrofit kits.
What equipment is the S4N250BW circuit breaker designed to fit?
This breaker is engineered for installation in legacy ABB switchboards, motor control centers, and Isomax S4 panelboards that accept unit-mount, bolt-on configurations.
What does the LI designation mean on the S4N250BW trip unit?
The LI designation indicates that the electronic trip unit provides adjustable Long-Time (L) protection for overloads and Instantaneous (I) protection for short circuits. This allows panel builders to precisely coordinate the breaker with other protective devices in the system.
How does the S4N250BW connect to the panel bus?
This model features a bolt-on connection type. It secures directly to the panel bus or mounting plate using standard hardware, providing a robust mechanical and electrical connection for high-amperage industrial applications.
Can auxiliary contacts and shunt trips be added to the S4N250BW?
Yes, the Isomax S4 frame is designed to accept various field-installable internal accessories. Electricians can integrate shunt trips, undervoltage releases, and auxiliary contacts to connect the breaker to facility control and alarm systems.
What are the advantages of the solid state trip unit on the S4N250BW?
The electronic solid state trip unit provides higher accuracy, better repeatability, and more precise adjustability than traditional thermal-magnetic mechanisms. This ensures tighter protection curves and improved safety for sensitive industrial loads.
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