Siemens NGB3K040B Molded Case Circuit Breaker
- 40A
- 3 Pole
- Bolt-On
Siemens
NGB3K040B
Molded Case Circuit Breaker
Brand
Siemens
SKU
NGB3K040B
Quantity
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Siemens NGB3K040B - 40A 3 Pole Molded Case Circuit Breaker
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Description
Built for heavy-duty commercial distribution, the Siemens NGB3K040B delivers 40 amps of thermal-magnetic protection across three poles. It provides reliable fault interruption with a 25kAIC rating at 480Y/277V. The unit mounts into Siemens P1, P2, and P3 panelboards, utilizing load-side lugs for secure wire terminations. This GB frame breaker features full HACR and reverse-feed ratings, offering an exact replacement option before upgrading to the 3VA51 series.Specifications
| Brand | Siemens |
|---|---|
| Series | NGB |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480Y/277VAC, 600Y/347VAC, 125/250VDC |
| Phase | 3 |
| 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, Padlock Attachment |
|---|---|
| Accessories | Load Lugs |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Reverse Feed |
Product FAQs
8 answersCan I install the Siemens NGB3K040B in a standard residential load center?
No, the NGB3K040B is a bolt-on molded case circuit breaker designed specifically for Siemens P1, P2, and P3 commercial lighting and distribution panelboards. It is not compatible with standard residential plug-on load centers.
What are the acceptable wire sizes and materials for the NGB3K040B terminals?
The factory-installed load side lugs on this breaker accept 8 to 1/0 AWG copper conductors or 8 to 2/0 AWG aluminum conductors. Ensure proper torque is applied per the label on the breaker faceplate during installation.
Is the NGB3K040B rated for DC applications?
Yes, this breaker is rated for DC systems up to 125/250VDC with an interrupting capacity of 14kAIC, making it suitable for specific direct current control and distribution circuits.
What does the LI trip function indicate on this breaker?
The LI designation means the breaker features Long-Time (thermal) and Instantaneous (magnetic) trip functions. On the NGB3K040B, both the thermal and magnetic trip settings are fixed and non-adjustable.
If I need a higher interrupting rating than 25kAIC at 480V, what are the alternatives to the NGB3K040B?
If your system requires a higher fault current rating at 480V, you can upgrade to the HGB or LGB frame equivalents, such as the HGB3B040B (rated 65kAIC at 480V) or the LGB3B040B (rated 100kAIC at 480V). Both share the same physical footprint and panelboard compatibility as the standard NGB frame.
What does the 600Y/347VAC voltage rating mean for installation?
The 600Y/347V rating indicates this breaker is designed for use in solidly grounded wye systems where the line-to-ground voltage does not exceed 347V, and the line-to-line voltage does not exceed 600V. It is not suitable for 600V ungrounded delta systems.
Is the NGB3K040B HACR rated?
Yes, like most modern Siemens Sentron molded case circuit breakers, the NGB3K040B is HACR rated, making it suitable for use with heating, air conditioning, and refrigeration equipment.
Does the NGB3K040B come with mounting hardware?
As a bolt-on breaker for P-series panelboards, it typically mounts directly to the panelboard bus using the integrated bolt-on connections. Depending on your specific P1, P2, or P3 panelboard configuration, twin mounting or single mounting kits may be required.
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Reviews
Review summary
Customers rate this product 4.5 out of 5 based on 8 reviews.
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Rating
8 reviews
- JHJohn H.Verified BuyerReviewingSiemens NGB3B015B - 15A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/16/26480v breakers
The breakers work great
- BPBland P.Verified BuyerReviewingSiemens NGB3B100 - 100A 3 Pole Molded Case Circuit BreakerI do not recommend this productRated 1 out of 5 stars7/22/26NO LUGS!!
I ordered this breaker and it arrived with no lugs. It was advertised as new so we didn't open the box and check until the shutdown we needed it for. When we discovered the lugs were missing we sent an email requesting a set overnighted. We didn't get a response for a couple of days, at which point we had already ordered lugs from their competitor Simply Breakers. They asked for pictures and questioned weather we had ordered the correct breaker asking if we needed lugs on both sides. This is a panel breaker and their is only one configuration that I am aware of which is bolted to bus in panel and wires to the three lugs on the other side. I have never had to order lugs separately for this style of breaker. They asked for pictures of box and what was in it, of course at this point the breaker is already installed and the box is thrown away. I sent a receipt for the overnight lugs from Simply breakers and asked for whatever credit they could provide. I received crickets to date. I have never had a problem with an order in the past from super breakers, but they are to busy to even respond to my request so I will think twice before I order anything from them again. It will be my last option once all others have been exhausted. Use Simply Breakers they have better stock and service.
- PFPaul F.Verified BuyerReviewingSiemens NGB3B060B - 60A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars6/24/26Great service, quick shippin
Need I say more.I have used SB. When we need it and need it quickly Always have what I need.
- BPBJ P.Verified BuyerReviewingSiemens NGB3B020B - 20A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars5/11/26NGB3B020B
I recently purchased the NGB3B020B and I’m very satisfied with the quality and performance. The breaker feels solid and well-made, and installation was straightforward. It works exactly as expected and provides reliable protection for my electrical setup. Shipping was fast and the product arrived in excellent condition. I would definitely purchase from this seller again.
- RSRadovan S.Verified BuyerReviewingSiemens NGB3B050B - 50A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars3/9/26Absolutely amazing service.
On Time