Maintaining aging industrial infrastructure is simpler with this 35-amp Federal Pacific bolt-on breaker. It delivers essential overload and short-circuit protection for 120/240V commercial branch circuits using proven thermal-magnetic trip technology. Electricians can mount this unit into existing NB or NBLP panelboards, bypassing the need for modern retrofits. It effectively replaces the UBIF235NB model. Built with a 10kA interrupting capacity, it accepts 14-2 AWG aluminum or copper wire.
Which panelboards accept the Federal Pacific NB221035 circuit breaker?
This breaker is specifically designed for Federal Pacific NB and NBLP series panelboards. It utilizes a bolt-on connection and is not compatible with standard plug-on load centers.
What does the NB frame designation mean for this breaker?
The NB frame indicates a specific physical footprint and bolt-on mounting style proprietary to Federal Pacific commercial panelboards. It cannot be interchanged with NA or NC series plug-on breakers.
What are the wire size and material requirements for the NB221035 terminals?
The integrated lugs accept conductor sizes ranging from 14 AWG to 2 AWG. The terminals are dual-rated for both copper (Cu) and aluminum (Al) wiring, making it versatile for existing commercial installations.
How is the NB221035 secured inside the panelboard?
It is a bolt-on miniature circuit breaker that fastens directly to the panelboard busbar with screws. This bolt-on design is typical for commercial applications, providing a highly secure connection that prevents arcing and resists vibration.
How does the thermal-magnetic trip unit function on the NB221035?
The breaker features a fixed thermal-magnetic trip mechanism with LI (Long-Time, Instantaneous) functions. The thermal element responds to prolonged overcurrent conditions, while the magnetic element trips instantaneously during a short circuit.
Is the Federal Pacific NB221035 still in active production?
Federal Pacific Electric (FPE) is no longer in business, so original NB221035 breakers are sourced from legacy inventory. They remain the standard drop-in solution for maintaining existing FPE NB and NBLP commercial panelboards.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 18 reviews.
Federal Pacific NB100 - 100A 2 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
7/2/26
100amp federal pacific breaker
So far the breaker works as expected
Just good to know some of these old federal are still available.
Thank you
SG
scott g.
Verified Buyer
Reviewing
Federal Pacific NB111020 - 20A 1 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
6/26/26
Hard to find breakers
Had a project at a school built in the 1960’s and thought we were up a creek when confronted with ancient FPE commercial panels. Luckily we found what we needed with Suoerbreakers.
BF
Barry F.
Verified Buyer
Reviewing
Federal Pacific NB100 - 100A 2 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
6/13/26
Hard to find circuit breaker
Item was as described.
WW
William W.
Verified Buyer
Reviewing
Federal Pacific NB100 - 100A 2 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
3/9/26
Exactly what I needed.
Awesome! Packaging and delivery were good. Bolted in and worked perfectly!!)
GH
Gary H.
Verified Buyer
Reviewing
Federal Pacific NB125 - 125A 2 Pole Miniature Circuit Breaker