Siemens NGB1B125B Molded Case Circuit Breaker
- 125A
- 1 Pole
- Bolt-On
Siemens
NGB1B125B
Molded Case Circuit Breaker
Brand
Siemens
SKU
NGB1B125B
Quantity
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Siemens NGB1B125B - 125A 1 Pole Molded Case Circuit Breaker
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Description
Built for heavy-duty commercial and industrial applications, the Siemens NGB1B125B is a 1-pole, 125-amp molded case circuit breaker. It provides dependable long-time and instantaneous trip functions to safeguard critical electrical circuits. This unit mounts into Siemens P1, P2, P3, P4, and P5 panelboards via a sturdy bolt-on connection. When planning future replacements, note that it is superseded by the 3VA5112-4ED16-0AA0, which requires an adapter kit for P1-P3 panels.Specifications
| Brand | Siemens |
|---|---|
| Part Number | NGB1B125B |
| Series | NGB |
| Amperage | 125A |
| Poles | 1 |
| Mounting Style | Bolt-On |
| Voltage | 120VAC, 240VAC, 277VAC, 125VDC, 347VAC |
| Phase | 1 |
| AIC Rating | 100kA @ 120VAC, 100kA @ 240VAC, 25kA @ 277VAC, 14kA @ 125VDC, 14kA @ 347VAC |
| Frame Type | GG |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P1, P2, P3, P4, P5 Panelboards |
| Wire Gauge | 8-1/0 AWG (Cu), 8-2/0 AWG (Al) |
| Max Wire | 1/0 AWG (Cu), 2/0 AWG (Al) |
| Min Wire | 8 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, Alarm Switch, Lug Kits |
|---|---|
| Accessories | Load Lugs |
| Standards | CSA C22.2 No. 5, HACR, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Reverse Feed |
Product FAQs
8 answersWhich panelboards are compatible with the NGB1B125B?
This breaker is designed for use in Siemens P1, P2, P3, P4, and P5 panelboards. It requires a specific branch breaker mounting kit depending on the panelboard type and whether it is a single-phase or three-phase system.
Can I install this Siemens NGB breaker in a GE or Square D panel?
No. Siemens NGB circuit breakers are strictly engineered and UL-listed for use in compatible Siemens panelboards. Using them in other brands of panels violates the UL listing and can create severe safety hazards.
What does the B suffix at the end of the NGB1B125B catalog number indicate?
The B suffix indicates that the breaker comes standard with load-side lugs installed from the factory.
Is the NGB1B125B suitable for DC voltage applications?
Yes, this breaker is rated for 125VDC applications with an interrupting capacity of 14kAIC, making it suitable for specific direct current control or distribution circuits.
What are the acceptable wire sizes for the factory-installed lugs?
The lugs accept 8 AWG to 1/0 AWG copper wire, or 8 AWG to 2/0 AWG aluminum wire. Always verify the correct torque specifications on the breaker side label before terminating the conductors.
Can I adjust the trip settings on the NGB1B125B?
No, this breaker features fixed thermal and fixed magnetic trip settings. It does not have adjustable trip dials for long-time or instantaneous functions.
What frame size does the NGB1B125B belong to?
This breaker is part of the Siemens GG frame family, often referred to as GB or GG frames, within the Sentron line of molded case circuit breakers.
Can this breaker be used in 277V commercial lighting circuits?
Yes, it is rated for 277VAC with an interrupting capacity of 25kAIC, making it suitable for 277V commercial applications.
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