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Siemens NGB3B020B Molded Case Circuit Breaker

  • 20A
  • 3 Pole
  • Bolt-On
Siemens NGB3B020B
Molded Case Circuit Breaker
Brand Siemens
SKU NGB3B020B
Select Item Condition
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  • 20A
  • 3 Pole
  • Bolt-On

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Siemens NGB3B020B - 20A 3 Pole Molded Case Circuit Breaker

Siemens NGB3B020B - 20A 3 Pole Molded Case Circuit Breaker

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$344.00 In Stock

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Description

Built for commercial panelboards, the Siemens NGB3B020B is a 20A, 3-phase molded case circuit breaker with thermal-magnetic trip technology. It provides reliable long-time and instantaneous protection for industrial systems. The breaker is designed to mount into Siemens P1, P2, and P3 panels using a secure bolt-on connection. Featuring HACR, HID, and SWD ratings, it supports versatile applications. For modern upgrades, it is replaced by the 3VA5120-4ED31-0AA0 using a mounting strap kit.

Specifications

Key specifications
Brand Siemens
Part Number NGB3B020B
Series NGB
Amperage 20A
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 14-6 AWG (Cu), 12-6 AWG (Al)
Max Wire 6 AWG
Min Wire 14 AWG (Cu), 12 AWG (Al)
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
Accessories Load Side Lugs Included (TC1Q1)
Standards CSA C22.2 No. 5, UL 489, NEMA AB 1
Approval CSA, HACR, HID, SWD, UL
Temp Rating 40C
Construction Features HACR Rated, HID Rated, Reverse Feed

Product FAQs

6 answers
What panelboards accept the Siemens NGB3B020B circuit breaker?

This branch breaker is designed specifically for installation in Siemens P1, P2, and P3 series lighting and distribution panelboards.

How does the NGB3B020B differ from Siemens BQD series breakers?

Both NGB and BQD series breakers share the same physical footprint and are used in Siemens P-series panelboards. However, the NGB series provides significantly higher interrupting capacities, such as 100kA at 240VAC, making it suitable for systems with higher available fault currents.

Can this 3-pole breaker be used in direct current (DC) systems?

Yes, the NGB3B020B carries a DC rating of 14kA at 125/250VDC, making it an appropriate choice for specific industrial controls, battery plants, and other DC power configurations.

What wire sizes do the factory lugs accommodate?

The factory-installed mechanical lugs accept 14 to 6 AWG copper wire and 12 to 6 AWG aluminum wire. Always ensure proper torque specifications are applied during termination.

How does the bolt-on mounting style benefit industrial installations?

Bolt-on breakers are fastened directly to the panelboard bus with screws. This creates a secure, low-resistance electrical connection that prevents loosening from vibration, which is critical in commercial and heavy industrial environments.

What protection does the fixed thermal-magnetic trip unit provide?

The non-adjustable thermal-magnetic (LI) trip mechanism offers dual-level safety. The thermal element responds to sustained overloads to prevent overheating, while the magnetic element trips instantaneously to clear severe short circuits and protect downstream equipment.

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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