Operating at up to 600Y/347VAC, the Siemens NGB3B045B is a 3-pole, 45A molded case circuit breaker. It provides essential LI protection for commercial electrical systems. This SENTRON series breaker bolts into Siemens P1, P2, P3, P4, and P5 panelboards. It features a trip-free mechanism, is HACR rated, and accepts standard lug connections. Offering 100kAIC at 240VAC, it delivers high-performance fault clearing. It is replaced by 3VA5145-4ED36-0AA0 (requires kit for P1-P3 panels).
Which Siemens panelboards accept the NGB3B045B breaker?
This bolt-on breaker is designed for use in Siemens P1, P2, P3, P4, and P5 series panelboards. It mounts directly to the panel bus using bolted connections.
What wire sizes and materials are supported by the lugs on this breaker?
The factory-installed lugs accept 8 AWG to 1/0 AWG copper wire, or 8 AWG to 2/0 AWG aluminum wire. Ensure proper torque specifications are followed during installation as noted on the breaker faceplate.
Can the NGB3B045B be used in DC applications?
Yes, this breaker is rated for DC systems up to 125/250V DC with a maximum interrupting capacity of 14kAIC.
Are the thermal and magnetic trip settings adjustable on the NGB3B045B?
No, this breaker features fixed thermal and fixed magnetic trip elements for both long-time and instantaneous protection.
What frame size does the NGB3B045B belong to?
It is part of the Siemens Sentron series GB and GG frame group. This is a compact molded case frame commonly used for branch circuit protection in commercial panelboards.
Does this breaker provide ground fault or arc fault protection?
No, the NGB3B045B provides standard thermal-magnetic protection for overloads and short circuits only. It does not include GFCI or AFCI circuitry.
How does the NGB3B045B connect to the panelboard bus?
It utilizes a bolt-on connection type. You will need the appropriate mounting hardware to secure the breaker directly to the busbars in compatible Siemens panelboards.
What is the maximum interrupting rating for this breaker on a 480V system?
When installed in a 480Y/277V AC system, the breaker carries a 25kAIC interrupting rating. For 240V AC systems, the rating increases to 100kAIC.
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Reviews
Review summary
Customers rate this product 4.5 out of 5 based on 8 reviews.
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