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Siemens NGB1B050B Molded Case Circuit Breaker

  • 50A
  • 1 Pole
  • Bolt-On
Siemens NGB1B050B
Molded Case Circuit Breaker
Brand Siemens
SKU NGB1B050B
Select Item Condition
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  • 50A
  • 1 Pole
  • Bolt-On

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Siemens NGB1B050B - 50A 1 Pole Molded Case Circuit Breaker

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$166.64 In Stock

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Description

Part of the Sentron family, this 50A single-pole molded case circuit breaker delivers robust thermal-magnetic protection for commercial and industrial electrical systems. It mounts into Siemens P1, P2, and P3 panelboards, providing a reliable bolt-on connection. Featuring a high 100kAIC rating at 120VAC and reverse feed capabilities, the NGB1B050B is HACR and HID rated for versatile load handling.

Specifications

Key specifications
Brand Siemens
Series NGB
Amperage 50A
Poles 1
Mounting Style Bolt-On
Voltage 120VAC, 277VAC, 125VDC, 347VAC
Phase 1
AIC Rating 100kA @ 120VAC, 25kA @ 277VAC, 14kA @ 125VDC, 14kA @ 347VAC
Fit and installation
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
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
Standards CSA C22.2 No. 5, UL 489, NEMA AB 1
Approval CSA, HACR, HID, UL
Temp Rating 40C
Construction Features HACR Rated, HID Rated, Reverse Feed

Product FAQs

6 answers
Which Siemens panelboards are compatible with the NGB1B050B circuit breaker?

This breaker is designed for use in Siemens P1, P2, and P3 panelboards. When installing in P2 or P3 panels, a specific branch mounting kit is required to connect the breaker to the panel bus.

What does the B suffix at the end of the NGB1B050B catalog number indicate?

The B suffix indicates that the circuit breaker is supplied with factory-installed load lugs as standard.

Can the NGB1B050B be used in reverse feed applications?

Yes. Because it features a non-interchangeable thermal-magnetic trip unit, it meets UL 489 requirements for reverse feed applications without requiring additional modifications.

Is this circuit breaker suitable for direct current (DC) systems?

Yes, the NGB1B050B is rated for DC applications and provides an interrupting capacity of 14kA at 125VDC.

What wire sizes and materials are accepted by the standard lugs on this breaker?

The factory-installed lugs accept 8 to 1/0 AWG copper (Cu) conductors or 8 to 2/0 AWG aluminum (Al) conductors.

Is the Siemens NGB1B050B HACR rated?

Yes, this breaker is HACR rated, making it suitable for use with heating, air conditioning, and refrigeration equipment that requires this specific listing.

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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