Built to support existing industrial applications, this 40A Federal Pacific molded case circuit breaker delivers essential thermal-magnetic protection. The N-frame device keeps older electrical systems running safely. The bolt-on configuration installs into legacy NEF panelboards, providing a seamless replacement solution. Facility managers can bypass the need for complex retrofits when swapping out aging components. Featuring an HACR rating, this unit handles 18kAIC at 240VAC.
Which panelboards accept the Federal Pacific NEF427040 circuit breaker?
This 2-pole breaker is designed as a direct bolt-on replacement for legacy Federal Pacific NEF panelboards. It allows facilities to maintain existing infrastructure without requiring aftermarket adapters or complete panel retrofits.
Can I use the NEF427040 in a residential Federal Pacific Stab-Lok panel?
No. The NEF427040 is a commercial N-frame molded case circuit breaker with a bolt-on mounting style. It is completely incompatible with residential Stab-Lok load centers, which require plug-on NA or NC type breakers.
What are the wire gauge requirements for the NEF427040?
The standard lug terminals on this breaker accommodate wire sizes from 14 AWG up to 2 AWG. Ensure you torque the connections to the manufacturer specifications during installation to prevent thermal issues.
Does the NEF427040 support DC voltage applications?
Yes, in addition to its AC ratings of up to 480VAC, this thermal magnetic breaker is rated for 250VDC systems, providing a 10kAIC interrupting capacity for direct current applications.
What does the LI trip function on the NEF427040 indicate?
The LI designation means the thermal magnetic trip unit provides Long-Time (L) protection against sustained overloads and Instantaneous (I) protection against severe short circuits. These trip settings are fixed and cannot be adjusted in the field.
Does this breaker require a separate mounting hardware kit?
When installing the NEF427040 into a Federal Pacific CDP or NEF panelboard, you may need a specific mounting hardware strap kit, such as the NEF1K, if the existing panel hardware is damaged or missing.
Is the NEF427040 interchangeable with other N-frame breakers?
The NEF427040 is part of the Federal Pacific N-frame family. While it shares physical dimensions with other N-frame breakers, it is specifically configured for bolt-on mounting in NEF panelboards. Always verify the panelboard type before attempting to interchange frames.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 6 reviews.
Federal Pacific NEF431030 - 30A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/21/26
Fpe 3 pole 30 amp breaker.
I ordered the breaker on Thursday and it was at my house for Saturday morning. Breaker is in pristine condition. A real bail out. Thank you.
MR
Michael R.
Verified Buyer
Reviewing
Federal Pacific NEF431040 - 40A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/4/25
Warehouse Air Compressor
Worked like a charm.
Thank you.
DP
Diana P.
Reviewing
Federal Pacific NEF433020 3 Pole Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
3/3/21
Satisfied
Service was GREAT!!
DJ
David J.
Reviewing
Federal Pacific / American NEF431100 - 100A 3 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
1/13/21
This worked out great.
This worked out great.
MW
Mark W.
Reviewing
Federal Pacific NEF421050 - 50A 2 Pole Molded Case Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
11/17/19
Great service & pricing
Superbreakers did a great job for us. We called and asked if the breakers were actually in their possession. Withing 30 minutes they called us back (which is rare these days), and we got our breakers the next morning.