Connecticut Electric UBIF250N 50 Amp Circuit Breaker for Level 2 EV Charging
The Connecticut Electric UBIF250N is a reliable 50A 2-pole replacement breaker for FPE NA panels. ETL listed, it handles 40A continuous EV charging loads and installs cleanly without panel mods.
The Connecticut Electric UBIF250N is a 50 Amp, 2-pole, thick-series Stab-Lok breaker made to replace Federal Pacific Electric NA-style breakers. It’s an ideal choice when installing a 240V 40A Level 2 EV charger or a 40A adjusted amperage Level 2 EV charger, especially in older homes with original Federal Pacific Stab-Lok panels. This breaker is newly manufactured—not reconditioned, and is ETL listed to UL 489 for use in the U.S. and Canada.
We recommend the UBIF250N when setting up a 240V 40A EV charger on a dedicated 240V 50A circuit. It fits securely in FPE load centers designed for NA-style thick breakers. The 2-inch body plugs in cleanly without looseness or poor contact, which are common in older Federal Pacific Electric panels. With a 10,000 AIC rating, this breaker meets the safety demands of high-powered charging loads required for Level 2 EV charging.
The UBIF250N is designed to replace the original Federal Pacific Electric NA250 breaker. That makes it a plug-and-play upgrade for NEC-compliant EV charger circuits in garages, carports, or dedicated EV charging subpanels.
We also tested this breaker with the Battery Tender eCharge 40 AMP EV Charger. This NEMA 14-50 plug-in charger delivers 9.6 kW when powered through a 50A circuit and plugged in a 14-50R outlet, the Battery Tender eCharge 40 AMP EV Charger performed flawlessly with no EV charger voltage dips, no 50A dedicated EV charger circuit breaker tripping, just steady, reliable 40A continuous loads charging even on extended durations of time. The breaker handled both the 32A and 40A EV charger loads with no performance issues.
In our wiring setup, we routed two #6 AWG hot wires and a #10 ground from the breaker to the NEMA 14-50R outlet that connects the Battery Tender eCharge 40 AMP EV Charger. The EV charger circuit wires ran through ¾” PVC conduit to the NEMA 14-50R outlet. No neutral was required for the 240V-only EVSE as shown in the wiring diagram below. The circuit was tested over 40+ charging hours with the Battery Tender eCharge 40 AMP EV Charger, and the breaker held firm with zero signs of wear or EV charging instability.
Installation was quick and clean. The terminals on the UBIF250N are clamped down securely, there was no need to modify the panel, upgrade/replace the old panel, or worry about code violations—this breaker is made for FPE thick NA-style slots and installs without fuss.
This breaker is perfect for powering 9.60 kW EV chargers in homes where panel space and compatibility are tight, whether you’re using a plug-in EVSE like the Battery Tender eCharge 40 AMP EV Charger, or a hardwired 40A Level 2 Level 2 EV charger, the UBIF250N is a safe, reliable breaker option.
Wiring the UBIF250N Breaker for a 240V Level 2 EV Charger
Although we used a NEMA 14-50 EV charger to test the Connecticut Electric UBIF250N—a 50 Amp, 2-pole, thick-style Stab-Lok breaker designed to replace Federal Pacific NA-type breakers—there are other ways to wire your circuit depending on your electrical panel and Level 2 EV charger configurations. Below are the most common 240V EV charger wiring setups using this breaker.
EV Charger Wiring – 240V (3-Wire: L1, L2, Ground) – UBIF250N Breaker
This is the standard hardwired setup for Level 2 EV chargers that don’t require a neutral, including both hardwired Level 2 EV chargers and plug-in NEMA 6-50 EV chargers using a NEMA 6-50 outlet. For example, the Enphase IQ 50 which is a hardwired charger, and the Grizzl-E Classic which uses a NEMA 6-50 plug on a 50A circuit. Use 6 AWG solid copper wires: two hots (L1 and L2) from the UBIF250N breaker, and one ground wire connected to the panel’s ground busbar – as shown in the wiring diagram below:
Compatible Level 2 EV Chargers for This Wiring Setup
The Enphase IQ 50 40 Amp Smart EV Charger delivers 9.6kW of power at 240V with a hardwired installation and a 25ft cable. Featuring Wi-Fi connectivity, a ruggedized J1772 connector, and safety certifications, it ensures reliable, efficient charging. Backed by a 5-year warranty, it's ideal for home use and future-proofing.
EV Charger Wiring – 240V (4-Wire: L1, L2, Neutral, Ground) – UBIF250N Breaker
This is the most common plug-in EV charger installation configuration for homes with original Federal Pacific Stab-Lok panels. Use this setup for Level 2 EV chargers that require a neutral, such as NEMA 14-50 plug-in EV chargers like the Grizzl-E Smart EV Charger – our top-rated home EV charger. The wiring of this EV charging circuit uses 6 AWG solid copper wires: two hot wires from the UBIF250N breaker, one neutral wire to the neutral busbar, and one ground wire to the ground busbar. This configuration supports both plug-in and hardwired installations, as shown in the wiring diagram below:
Compatible Level 2 EV Chargers for This Wiring Setup
EV Charger Wiring – 240V (3-Wire: L1, L2, Neutral, No Ground) – UBIF250N Breaker
This older method includes two hots and a neutral one with no ground. It may exist in legacy NEMA 10-50 EV charger installations using original Federal Pacific Stab-Lok panels where neutral is bonded to the ground. Not recommended by current NEC standards. Use only if the charger supports it and local code allows — as shown in the wiring diagram below:
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