The NGB3B030B is a 3-pole, 30A molded case circuit breaker from Siemens, built for commercial and industrial branch circuits. It delivers dependable long-time and instantaneous thermal-magnetic protection. This bolt-on MCCB installs into Siemens P1, P2, P3, P4, and P5 panelboards. It is replaced by the 3VA5130-4ED36-0AA0, which requires a mounting kit for legacy panels. Rated at 100kAIC at 240VAC and 25kAIC at 480Y/277VAC, it handles high fault currents. It is HACR and HID rated.
What panels are compatible with the Siemens NGB3B030B circuit breaker?
This molded case breaker is designed to bolt directly into the bus bars of Siemens P1, P2, P3, P4, and P5 series panelboards.
Does the NGB3B030B include terminal lugs on both ends?
No. Because it is a panelboard-mounted circuit breaker, it utilizes a bolt-on connection for the line side and comes standard with a load-side lug only.
What wire sizes are accepted by the load lug on this breaker?
The factory-installed lug accommodates 14 to 6 AWG copper wire or 12 to 6 AWG aluminum conductors.
Can the NGB3B030B be used in reverse-feed applications?
Yes, this Sentron series thermal-magnetic breaker is suitable for reverse-feed configurations because its internal trip unit is not removable or interchangeable. It is also HACR and HID rated for specialized loads.
Is there a direct replacement for the NGB3B030B?
Yes, Siemens has transitioned to the 3VA5130-4ED36-0AA0 as the modern equivalent for this model. If you are installing the newer 3VA breaker into legacy P1 through P5 panelboards, a separate mounting hardware kit will be required.
Does the NGB3B030B feature adjustable trip settings?
No, this model is equipped with a fixed thermal and fixed magnetic trip unit. It delivers dependable long-time and instantaneous (LI) protection that cannot be field-adjusted.
Is this breaker suitable for direct current (DC) electrical systems?
Yes, in addition to standard AC voltages, the NGB3B030B is rated for DC applications. It provides a 14kAIC interrupting capacity when used on 125/250VDC circuits.
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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