Federal Pacific NK631125 Molded Case Circuit Breaker
- 125A
- 3 Pole
- Bolt-On
Federal Pacific
NK631125
Molded Case Circuit Breaker
Brand
Federal Pacific
SKU
NK631125
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Federal Pacific NK631125 - 125A 3 Pole Molded Case Circuit Breaker
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125A 3 Pole Molded Case Circuit Breaker
125A 3 Pole Molded Case Circuit Breaker
Description
Built for industrial applications, the Federal Pacific NK631125 is a 125-amp, 3-pole molded case circuit breaker. It utilizes a non-interchangeable trip unit to deliver long-time and instantaneous protection. Designed to restore aging infrastructure, this legacy component bolts seamlessly into existing Federal Pacific panelboards. It guarantees an exact fit, eliminating the need for retrofit kits. The breaker handles up to 600VAC and includes load-side lugs for 6 AWG to 300 kcmil wire.Specifications
| Brand | Federal Pacific |
|---|---|
| Series | NK |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 42kA @ 240VAC, 30kA @ 480VAC, 20kA @ 600VAC |
| Frame Type | NK |
|---|---|
| Terminal Type | Lugs |
| For Use With | Federal Pacific Panelboards, Switchboards |
| Wire Gauge | 6 AWG - 300 kcmil |
| Max Wire | 300 kcmil |
| Min Wire | 6 AWG |
| 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 | Load Side Lugs Included |
| Standards | UL 489, NEMA AB-1 |
| Approval | UL |
| Temp Rating | 40°C |
| Construction Features | Non-Interchangeable Trip, Common Trip |
Product FAQs
6 answersWhat types of enclosures or panels is the NK631125 designed for?
This bolt-on breaker is designed for legacy Federal Pacific Electric (FPE) panelboards and switchboards that accommodate NK-frame molded case circuit breakers.
What is the maximum frame rating for the NK631125?
This breaker is built on a 225A maximum N-frame chassis, but it is factory-equipped with a 125A fixed thermal trip unit. This allows it to fit into standard N-frame spaces within FPE switchboards while properly protecting 125A circuits.
What wire size range do the lugs on the NK631125 accept?
The standard lugs for this breaker accept wire gauges from 6 AWG up to 300 kcmil. Ensure your conductors are sized appropriately for the continuous current rating and torque the lugs to the manufacturer specifications.
How does the adjustable magnetic trip function work on this breaker?
While the thermal overload trip is fixed, the magnetic instantaneous trip is adjustable. This allows electricians to tune the short-circuit response threshold to coordinate with downstream devices or handle specific motor inrush currents without nuisance tripping.
Is this breaker part of the FPE Stab-Lok residential line?
No. The NK631125 is a commercial-grade, bolt-on molded case circuit breaker used in heavy-duty panelboards and switchboards. It does not use the Stab-Lok plug-on connection system found in older residential load centers.
Can I use this breaker to replace other FPE N-frame breakers?
Yes, the NK631125 can typically replace other 125A NK-frame breakers in Federal Pacific equipment, provided the interrupting ratings meet or exceed the available fault current at the installation point.
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