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Siemens NGB3B040B Molded Case Circuit Breaker

  • 40A
  • 3 Pole
  • Bolt-On
Siemens NGB3B040B
Molded Case Circuit Breaker
Brand Siemens
SKU NGB3B040B
Select Item Condition
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  • 40A
  • 3 Pole
  • Bolt-On

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Siemens NGB3B040B - 40A 3 Pole Molded Case Circuit Breaker

Siemens NGB3B040B - 40A 3 Pole Molded Case Circuit Breaker

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$334.60 In Stock

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Description

Engineered for commercial applications, the Siemens NGB3B040B is a 3-pole, 40A molded case circuit breaker from the SENTRON family. It provides dependable thermal-magnetic trip protection. This bolt-on MCCB installs into Siemens P1, P2, and P3 panelboards. It features a reverse-feed capable design and accepts 8-1/0 AWG copper wire via standard lugs. Rated for 100kAIC at 240VAC and 25kAIC at 480Y/277VAC. Note that this unit is replaced by the 3VA51 series, which requires a mounting kit.

Specifications

Key specifications
Brand Siemens
Part Number NGB3B040B
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
Fit and installation
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
Protection and operation
Trip Technology Thermal Magnetic
Trip Function Code LI
Trip Function Long-Time, Instantaneous
Trip Adjustability Fixed Thermal, Fixed Magnetic
Standards and features
Available Options Shunt Trip, Auxiliary Switch, Alarm Switch, Padlock Attachment
Accessories Load Side Lugs (3TC1GG20)
Standards CSA C22.2 No. 5, UL 489, NEMA AB 1
Approval CSA, HACR, UL
Temp Rating 40C
Construction Features HACR Rated, Reverse Feed

Product FAQs

8 answers
Which Siemens panelboards are compatible with the NGB3B040B?

This bolt-on molded case circuit breaker is designed for direct installation in Siemens P1, P2, and P3 panelboards.

Does this breaker include both line and load-side lugs?

No. Because it is designed for panelboard mounting, the line side bolts directly to the panel bus. Mechanical lugs are provided on the load side only.

Can the NGB3B040B circuit breaker be reverse fed?

Yes. The thermal-magnetic trip unit is non-interchangeable, making this breaker suitable for reverse-feed applications.

Is the Siemens NGB3B040B suitable for HVAC equipment?

Yes. This breaker is HACR rated, meaning it is certified for use with heating, air conditioning, and refrigeration systems.

Can this 40A NGB breaker be used in DC branch circuits?

Yes. It is rated for DC distribution applications up to 125/250VDC with a maximum interrupting capacity of 14kAIC.

What size wire do the NGB3B040B lugs accept?

The factory-installed load-side lugs accept 8 to 1/0 AWG copper wire or 8 to 2/0 AWG aluminum wire.

Are the trip settings adjustable on this NGB breaker?

No. It features fixed thermal (long-time) and fixed magnetic (instantaneous) trip functions that cannot be modified in the field.

Can I use this breaker to replace an older ITE NGB3B040B?

Yes. Siemens manufactures the current NGB series as a direct replacement for legacy ITE breakers sharing the same catalog number and frame size.

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Reviews

4.5
Rated 4.5 out of 5 stars
Based on 8 reviews
Rating
Ratings
8 reviews
  • JH
    John H.
    Verified Buyer
    Reviewing
    Siemens NGB3B015B - 15A 3 Pole Molded Case Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    9/16/26
    480v breakers

    The breakers work great

  • BP
    Bland P.
    Verified Buyer
    Reviewing
    Siemens NGB3B100 - 100A 3 Pole Molded Case Circuit Breaker
    I do not recommend this product
    Rated 1 out of 5 stars
    7/22/26
    NO 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.

  • PF
    Paul F.
    Verified Buyer
    Reviewing
    Siemens NGB3B060B - 60A 3 Pole Molded Case Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    6/24/26
    Great service, quick shippin

    Need I say more.I have used SB. When we need it and need it quickly Always have what I need.

  • BP
    BJ P.
    Verified Buyer
    Reviewing
    Siemens NGB3B020B - 20A 3 Pole Molded Case Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    5/11/26
    NGB3B020B

    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.

  • RS
    Radovan S.
    Verified Buyer
    Reviewing
    Siemens NGB3B050B - 50A 3 Pole Molded Case Circuit Breaker
    I recommend this product
    Rated 5 out of 5 stars
    3/9/26
    Absolutely amazing service.

    On Time