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Siemens NGB2B040B Molded Case Circuit Breaker
- 40A
- 2 Pole
- Bolt-On
Siemens
NGB2B040B
Molded Case Circuit Breaker
Brand
Siemens
SKU
NGB2B040B
Quantity
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Siemens NGB2B040B - 40A 2 Pole Molded Case Circuit Breaker
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Description
Built for industrial power distribution, this 40A Siemens molded case circuit breaker delivers robust thermal-magnetic protection. It operates across 600Y/347VAC and 125/250VDC systems to safeguard critical commercial infrastructure. The bolt-on design installs into Siemens P1, P2, and P3 panelboards. When replacing this NGB frame, the newer 3VA51 series serves as a substitute but requires a mounting strap kit. This breaker features a 100kAIC rating at 240V and includes load side lugs.Specifications
| Brand | Siemens |
|---|---|
| Part Number | NGB2B040B |
| Series | NGB |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480Y/277VAC, 600Y/347VAC, 125/250VDC |
| Phase | 1 |
| AIC Rating | 100kA @ 240VAC, 25kA @ 480Y/277VAC, 14kA @ 600Y/347VAC, 14kA @ 125/250VDC |
| Frame Type | NGB |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P1, P2, P3 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 |
|---|---|
| Accessories | Load Side Lugs |
| Standards | CSA C22.2 No. 5, UL 489, NEMA AB 1 |
| Approval | CSA, HACR, HID, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Reverse Feed |
Product FAQs
7 answersWhat panelboards are compatible with the Siemens NGB2B040B?
This bolt-on circuit breaker is designed specifically for installation in Siemens P1, P2, and P3 lighting and distribution panelboards.
Can the NGB2B040B be reverse fed?
Yes, this breaker is suitable for reverse feed applications, allowing it to be back-fed when used as a main or sub-feed breaker in compatible panels.
What wire sizes are accepted by the load lugs on this 40A breaker?
The included load-side lugs accept 8 to 1/0 AWG copper (Cu) conductors or 8 to 2/0 AWG aluminum (Al) conductors.
Is the Siemens NGB2B040B rated for DC voltage applications?
Yes, it is rated for use in DC systems up to 125/250VDC, providing an interrupting capacity of 14kAIC for direct current applications.
Is this circuit breaker HACR rated?
Yes, the NGB2B040B carries an HACR rating, making it suitable for protecting heating, air conditioning, and refrigeration equipment circuits.
What is the modern replacement for the Siemens NGB frame?
Siemens is transitioning from the legacy NGB frame to the newer 3VA51 series. Installing a 3VA replacement breaker into existing P1, P2, or P3 panelboards requires a specific retrofit mounting kit.
Does the NGB2B040B provide GFCI or AFCI protection?
No, this is a standard thermal magnetic circuit breaker. It does not provide ground fault or arc fault circuit interruption.
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