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Eaton / Cutler-Hammer HFB3100 Molded Case Circuit Breaker
- 100A
- 3 Pole
- Bolt-On
Eaton / Cutler-Hammer
HFB3100
Molded Case Circuit Breaker
Brand
Eaton / Cutler-Hammer
SKU
HFB3100
Quantity
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Eaton / Cutler-Hammer HFB3100 - 100A 3 Pole Molded Case Circuit Breaker
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100A 3 Pole Molded Case Circuit Breaker
100A 3 Pole Molded Case Circuit Breaker
Description
Manufactured for heavy-duty electrical distribution, this 100-amp F-Frame breaker features fixed thermal and magnetic trip elements. The unit mounts into legacy Westinghouse FDP enclosures as well as modern Eaton Pow-R-Line C panelboards. With a maximum voltage rating of 600VAC and 250VDC, it accommodates a wide range of industrial setups. This specific Mark 75 series component is HACR rated for heating and cooling systems, though it has been superseded by the HFD3100 in current catalogs.Specifications
| Brand | Eaton / Cutler-Hammer |
|---|---|
| Part Number | HFB3100-R |
| Series | HFB |
| Amperage | 100A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 65kA @ 240VAC, 25kA @ 480VAC, 18kA @ 600VAC, 10kA @ 250VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Westinghouse FDP Panelboards, Eaton Pow-R-Line C Panelboards, F-Frame Switchboards |
| Wire Gauge | 14-1/0 AWG (Cu/Al) |
| Max Wire | 1/0 AWG |
| Min Wire | 14 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch |
|---|---|
| Accessories | Load Side Lugs |
| Standards | NEMA AB-1, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | High Interrupting Capacity, HACR Rated, Reverse Feed, Non-Interchangeable Trip |
Product FAQs
7 answersWhich panelboards are compatible with the HFB3100?
This 100A F-frame breaker bolts directly into legacy Westinghouse FDP panelboards, modern Eaton Pow-R-Line C panelboards, and standard F-frame switchboards.
Is there a physical difference between Westinghouse, Cutler-Hammer, and Eaton versions of the HFB3100?
No. Following historical corporate acquisitions, the HFB3100 part number remained consistent. Breakers branded under Westinghouse, Cutler-Hammer, or Eaton are structurally identical, carry the exact same Mark 75 F-frame dimensions, and are direct drop-in replacements for one another.
Has the HFB3100 been discontinued or replaced by Eaton?
Yes, the original Mark 75 HFB frame is classified as obsolete in modern Eaton catalogs. For complete breaker replacement, Eaton recommends the Series C FD3100 or HFD3100 as the current-production substitute. However, the exact HFB3100 is still frequently sourced by electricians to match existing panel profiles without modifying bus arrangements.
How does the HFB3100 connect to the panel bus?
This F-frame breaker uses a standard bolt-on mounting configuration. The line side bolts directly to the busbars of compatible Eaton Pow-R-Line C or legacy Westinghouse panels without requiring separate mounting brackets, while the load side uses standard mechanical lugs.
Can the trip settings on the HFB3100 be adjusted for different loads?
No. This breaker features a non-interchangeable, fixed thermal and fixed magnetic trip unit. The Long-Time and Instantaneous (LI) protection parameters are factory-sealed to protect exactly at its rated capacity, meaning the trip curve cannot be dialed up or down.
How does the interrupting capacity (AIC) affect system safety?
The 65kA Ampere Interrupting Capacity (AIC) at 240VAC indicates the maximum short-circuit fault current this breaker can safely clear. Always confirm that your system's available fault current does not exceed the breaker's rated AIC at your specific operating voltage, as this protection capacity decreases at higher voltages, such as 25kA at 480VAC.
Can the HFB3100 be reverse fed?
Yes. Because it relies on standard thermal-magnetic trip technology without directional electronic components, the HFB3100 is generally suitable for reverse-feed (back-feed) applications. Always verify that there are no Line and Load markings stamped on your specific unit and consult local NEC codes before back-feeding.
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