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Connecticut Electric UBITBA250 50A Challenger Type A Breaker for Level 2 EV Chargers

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Connecticut Electric UBITBA250 is a new, UL-listed 50 Amp 2-pole breaker for Challenger Type A panels. Ideal for 240V 40A Level 2 EV chargers like the Mustart 9.6 kW Level 2 EV charger.

The Connecticut Electric UBITBA250 New Challenger MH250 Type-A Replacement Two Pole 50 Amp Clip Circuit Breaker is an ideal solution for replacing outdated breakers in Challenger Type-A panels – especially when installing a 240V 40A Level 2 EV charger or a 9.60 kW EV charger. This breaker is specifically designed for use in Challenger Type-A load centers and is manufactured brand new, not refurbished, by Connecticut Electric. The circuit breaker is ETL listed to UL Standard 489 and rated for 10,000 AIC, offering the reliability required for a high-load Level 2 EV charger.

Challenger Type-A breaker panels were commonly installed in homes from the 1960s through the 1980s. While they were compliant at the time, many of these panels now pose challenges due to aged busbars, loose contact points, and limited compatibility with modern UL-listed breakers. Some older breakers in these panels are known for failing to trip under fault conditions, which is why it’s critical to replace them with new safety-certified units when installing a 40 A Level 2 EV charger.

As a certified EV charger installer, I often come across Challenger panels in homes that need a safe and robust 50A circuit to support high-amperage Level 2 EV chargers. While many homeowners opt for panel upgrades or replacements, if the existing panel has enough capacity to support a 240V 40A Level 2 EV charger, the Connecticut Electric UBITBA250 2-pole 50 Amp breaker is a recommended option, Its slim, 1-inch profile and secure clip-in mounting make it a great fit for tight panels with limited space, and delivers the performance needed to safely run a 40A EV charger – such as the Mustart 40 Amp EV Charger, which we tested extensively in this setup.

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MUSTART Level 2 EV Charger, 40 Amp, 240 Volt, 25ft Cable, Electric Vehicle Portable Charger Plug-in EV Charging Station with NEMA 14-50P, ETL Certificated
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The Mustart 40 Amp EV Charger delivers fast 240V charging with a 25-foot cable and NEMA 14-50P plug for easy installation. ETL-certified for safety, this portable plug-in station is ideal for home use, providing reliable, high-speed charging for all-electric vehicles with convenience and efficiency.

We tested the UBITBA250 using the Mustart 40 Amp EV Charger installed on a dedicated 50A EV charging circuit wired with 6 AWG solid copper conductors in ¾-inch conduit (Schedule 40 PVC) from the main panel to a NEMA 14-50 outlet. The neutral and ground conductors were properly terminated at the panel’s neutral and bonded ground busbars as shown in the wiring diagram below. This circuit was built specifically to power a Mustart 40 Amp EV Charger, rated for 9.60 kW of continuous output at 240V.A detailed wiring diagram illustrating the connection of a 40A Level 2 EV charger to a single-phase Federal Pacific electrical panel, using a Connecticut Electric UBITBA250 50A 2-pole breaker in compliance with US National Electrical Code (NEC) standards. Electrical Panel (Left): Power input from the utility is shown, with L1 (Hot 1 - black wire), L2 (Hot 2 - red wire), and Neutral (N - white wire). Active lugs on the main breaker are highlighted, with a warning indicating they are always live. The main panel breaker is located at the top. The dedicated EV charger circuit breaker is a CB1-50A 2P Connecticut Electric (UBITBA250), connected to L1 and L2 busbars. The neutral busbar connects the utility neutral and the EV circuit neutral (white wire). The ground (G) busbar connects the EV circuit ground (green wire) and the main earth conductor. Electrical bonding between the neutral and ground busbars is shown. The earth conductor connects the ground busbar to an external ground rod, which is connected to Ground/Earth. A warning advises keeping branch circuit wiring neat and away from breakers and gutter posts. Wiring and Conduit (Center): Wires (L1 - black, L2 - red, N - white, G - green) run from the panel breaker (L1, L2), neutral busbar (N), and ground busbar (G) through a 3/4" conduit. Specified wiring is 6 AWG 90C Copper Wire for the EV charger circuit. A note addresses voltage drop, advising upsizing wires on long runs to maintain a voltage drop of less than 3% per NEC guidelines. EV Charger Connection (Right): The four wires (L1, L2, N, G) terminate at a NEMA 14-50 style receptacle, depicted with four prongs. An icon represents the 40A Level 2 EV charger and its plug. The text indicates a 9.6kW EV charger (240V = 40A). A prominent warning states: "40A charger needs a 50A breaker per NEC 80% rule." Overall title: "40A EV Charger Wiring Diagram with UBITBA250 Breaker - Connecting a 40A EV Charger to a Federal Pacific Panel." Includes the "Electric Vehicle Geek" logo and the label "Single Phase Panel Wiring (US-NEC)."

Over several full charging sessions – from near-empty to 80% and from 80% to full, we monitored the performance of the 50A EV charger circuit closely. There was no tripping, voltage drop, breaker hum, overheating, or contact instability experienced during our test. The UBITBA250 maintained stable power delivery across all test cycles. The breaker remained cool to the touch even after continuous 8- to 10-hour Level 2 EV charging sessions at 40 amps, showing no signs of heat or mechanical wear.

Wiring the UBITBA250 Breaker for a 240V Level 2 EV Charger

When installing a 240V Level 2 EV charger using the Connecticut Electric UBITBA250 breaker in a Challenger Type-A panel, proper wiring is essential for safety, performance, and code compliance. While our test setup used a NEMA 14-50 outlet, there are several other ways to wire the breaker depending on your EV charger’s requirements and your panel configuration. Below are the most common circuit wiring configurations using the UBITBA250 breaker, including diagrams for complete Level 2 EV charger installations.

EV Charger Wiring – 240V (4-Wire: L1, L2, Neutral, Ground) – UBITBA250 Breaker

The Connecticut Electric UBITBA250 breaker is commonly used for installing plug-in NEMA 14-50 Level 2 EV chargers with a NEMA 14-50 outlet. EV chargers like the Grizzl-E Smart EV Charger often follow this configuration, It’s also frequently used by electricians when converting plug-in NEMA 14-50 setups to hardwired installations. This wiring method typically uses 6 AWG solid copper conductors: two hot wires (L1 and L2), one neutral, and one ground. The UBITBA250 double-pole breaker supplies the two hot legs, while the neutral and ground are connected to their respective busbars — as shown in the wiring diagram below:Diagram titled 'EV Charger Wiring - 240V (4-Wire: L1, L2, Neutral, Ground) - UBITBA250 Breaker' from electricvehiclegeek.com. It illustrates how to wire a 240V EV charger. The diagram shows: Power from Utility (L1 Hot 1, L2 Hot 2, N Neutral) entering a main electrical panel. Inside the panel: Active Lugs on Main Breaker (noted as continuously live), the Main Panel Breaker, an EV Charger Dedicated Circuit Breaker (specified as CB1 - 50A 2P Connecticut Electric UBITBA250), Neutral Busbar, and G (Ground Busbar) with Electrical Bonding shown between them. An Earth Conductor connects the Ground Busbar to a Ground Rod. A 240V EV Charger Branch Circuit (L1, L2, N & G) exits the panel through 3/4" conduit. Wiring is specified as 6 AWG 90C Copper Wire. A warning states to keep branch circuit wiring outside gutter posts and avoid crossing wires over breakers. Another note advises upsizing wires on long runs to keep voltage drop under 3% per NEC. The branch circuit leads to either a NEMA 14-50 Outlet for a Plug-in EV Charger or to a Hardwired EV Charger. Terminal wiring for hardwired is L1-LINE 1 (Black), L2-LINE 2 (Red), N-NEUTRAL (White), G-GROUND (Green). Information for a '40 A Level 2 EV Charger' (9.6kW, 240V=40A) is shown, with an icon of a charger nozzle. A crucial warning states: '40A charger needs a 50A breaker per NEC 80% rule.' The Electric Vehicle Geek logo is in the bottom left corner.

Compatible Level 2 EV Chargers for This Wiring Setup

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WOLFBOX Level 2 EV Charger 40 Amp - Smart Display, RFID Card, 25ft Cable, Outdoor/Indoor, NEMA 14-50 EV Charger Level 2, WiFi Enabled, 240V Electric Vehicle Charging Station for Electric Automobile
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EG evgoer Level 2 EV Charger, 40A 240V Portable EV Home Charging Station, Schedule Time 8-40A Adjustable Current Electric Vehicle Charger Compatible with All J1772 EVs (20 ft)
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Battery Tender eCharge 48 AMP EV Charger - Level 2 Mounted Indoor Outdoor Fast Electric Vehicle Charging Station with Flexible 25ft Cable NEMA 14-50 - 022-3019-DL-WH
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The Battery Tender eCharge 48 AMP EV Charger is a high-capacity Level 2 electric vehicle charger, optimized for 240V power to deliver rapid charging. Designed for both indoor and outdoor use, this powerful charger is ideal for high-demand EV charging scenarios, ensuring fast and reliable power for your electric vehicle.
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Battery Tender eCharge 40 AMP EV Charger - Level 2 Mounted Indoor Outdoor Fast Electric Vehicle Charging Station with Flexible 25ft Cable NEMA 14-50 - 022-3018-DL-WH
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EV Charger Wiring – 240V (3-Wire: L1, L2, Ground) – UBITBA250 Breaker

This is the most common hardwired configuration for Level 2 EV chargers that do not require a neutral wire, It’s often used for hardwired Level 2 EV charger installations like the Tesla Wall Connector on a 50A circuit and also applies to NEMA 6-50 Level 2 chargers that use a NEMA 6-50 outlet. For EV chargers that operate exclusively at 240V, this setup is both safe and code-compliant – this configuration uses 6 AWG solid copper wires. The two hot wires deliver 240V from the UBITBA250 breaker, and the ground wire connects to the panel’s ground busbar — as shown in the wiring diagram below:Diagram titled 'EV Charger Wiring - 240V (3-Wire: L1, L2, Ground) - UBITBA250 Breaker' from electricvehiclegeek.com. It illustrates how to wire a 240V EV charger using a 3-wire setup. The diagram shows: Power from Utility (L1 Hot 1, L2 Hot 2, N Neutral) entering a main electrical panel. Inside the panel: Active Lugs on Main Breaker (noted as continuously live), the Main Panel Breaker, an EV Charger Dedicated Circuit Breaker (specified as CB1 - 50A 2P Connecticut Electric UBITBA250), Neutral Busbar, and G (Ground Busbar). Electrical Bonding is shown connecting the Neutral and Ground busbars. A 240V EV Charger Branch Circuit (L1, L2, & G) exits the panel through 3/4" Conduit. Wiring is specified as 6 AWG 90C, Copper Wire. A warning states to keep branch circuit wiring outside gutter posts and avoid crossing wires over breakers. Another note advises upsizing wires on long runs to keep voltage drop under 3% per NEC. The branch circuit leads to either a NEMA 6-50 Outlet (labeled 'G' for ground, two vertical slots) for a Plug-in EV Charger or to a Hardwired EV Charger. Terminal wiring for hardwired is L1-LINE 1 (Black), L2-LINE 2 (Red), G-GROUND (Green). Information for a '40 A Level 2 EV Charger' (9.6kW EV charger, 240V = 40A) is shown, with an icon of a charger nozzle. A crucial warning states: '40A charger needs a 50A breaker per NEC 80% rule.' Grounding: An Earth Conductor connects the Ground Busbar to a Ground Rod and then to Ground/Earth. The Electric Vehicle Geek logo is in the bottom left corner.

Compatible Level 2 EV Chargers for This Wiring Setup

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EMPORIA Pro Level 2 EV Charger with PowerSmart - 48 amp Fast Charger with NEMA 14-50 or Hardwire and J1772 Connector - 240v Electric Vehicle Charging Station and 25' EV Charging Cable
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Emporia Pro EV Charger offers 48A fast Level 2 EV charging with PowerSmart Load Management. Includes NEMA 14-50 plug or hardwire installation options, 25' cable, and real-time energy optimization for efficient charging.
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WOLFBOX Level 2 EV Charger 40 Amp - Smart Display, RFID Card, 25ft Cable, Outdoor/Indoor, NEMA 14-50 EV Charger Level 2, WiFi Enabled, 240V Electric Vehicle Charging Station for Electric Automobile
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The WOLFBOX Level 2 EV Charger is a home Level 2 EV charger that offers fast, reliable charging with a sleek, weatherproof design. Featuring a 25ft cable, smart app integration, and compatibility with all J1772 EVs, it’s perfect for both home and public use. Choose between plug-in or hardwired models for convenient, future-proof charging at any location.
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Battery Tender eCharge 48 AMP EV Charger - Level 2 Mounted Indoor Outdoor Fast Electric Vehicle Charging Station with Flexible 25ft Cable NEMA 14-50 - 022-3019-DL-WH
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The Battery Tender eCharge 48 AMP EV Charger is a high-capacity Level 2 electric vehicle charger, optimized for 240V power to deliver rapid charging. Designed for both indoor and outdoor use, this powerful charger is ideal for high-demand EV charging scenarios, ensuring fast and reliable power for your electric vehicle.
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Battery Tender eCharge 40 AMP EV Charger - Level 2 Mounted Indoor Outdoor Fast Electric Vehicle Charging Station with Flexible 25ft Cable NEMA 14-50 - 022-3018-DL-WH
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The Battery Tender eCharge 40 AMP EV Charger is a high-performance Level 2 electric vehicle charger, designed for 240V power to deliver fast and efficient charging. Compatible with NEMA 14-50P or hardwired setups, this robust charger is perfect for both home and public use, offering reliable, high-speed charging for your EV.
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EMPORIA Level 2 EV Charger - NEMA 14-50 EVSE w/NACS, Compatible with Tesla - 48 amp EV Charger Level 2, 240v Electric Vehicle Charging Station, UL/Energy Star, 24ft Electric Car Charger Cable, Black
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The Emporia Level 2 EV Charger with NACS delivers fast, reliable charging for Tesla and NACS vehicles. It offers up to 46 miles of range per hour, features easy installation, and is UL-listed for safety. Smart charging capabilities and durable construction make it a great value at a competitive price.

EV Charger Wiring – 240V (3-Wire: L1, L2, Neutral, No Ground) – UBITBA250 Breaker

This older method uses two hot wires and a neutral but lacks a dedicated ground. It may be found in legacy installations where neutral was bonded to the panel as shown in the wiring diagram below. However, it is not recommended under current NEC standards due to safety concerns. Use this configuration only if the charger is compatible such as NEMA 10-50 Level 2 EV chargers and local codes explicitly allow it.Diagram titled 'EV Charger Wiring - 240V (3-Wire: L1, L2, Neutral, No Ground) - UBITBA250 Breaker' from electricvehiclegeek.com. It illustrates an outdated method of wiring a 240V EV charger without a dedicated ground wire in the branch circuit.
The diagram shows:
Power from Utility (L1 Hot 1, L2 Hot 2, N Neutral) entering a main electrical panel.
Inside the panel: Active Lugs on Main Breaker (noted as continuously live), the Main Panel Breaker, an EV Charger Dedicated Circuit Breaker (specified as CB1 - 50A 2P Connecticut Electric UBITBA250), Neutral Busbar, and G (Ground Busbar). Electrical Bonding is shown between the Neutral and Ground busbars.
A 240V EV Charger Branch Circuit (L1, L2, & N) exits the panel through 3/4" Conduit. This branch circuit lacks a dedicated ground wire. Wiring is specified as 6 AWG 90C, Copper Wire.
A warning states to keep branch circuit wiring outside gutter posts and avoid crossing wires over breakers. Another note advises upsizing wires on long runs to keep voltage drop under 3% per NEC.
The branch circuit leads to either a NEMA 10-50 Outlet (labeled W for neutral, X and Y for hot) for a Plug-in EV Charger or to a Hardwired EV Charger. Terminal wiring for hardwired is L1-LINE 1 (Black), L2-LINE 2 (Red), N-NEUTRAL (White).
Information for a '40 A Level 2 EV Charger' (9.6kW EV charger, 240V = 40A) is shown, with an icon of a charger nozzle.
A warning states: '40A charger needs a 50A breaker per NEC 80% rule.'
A critical warning at the bottom states: 'The configuration (L1, L2, N - no ground) is outdated and not permitted under modern NEC requirements for EV chargers. According to NEC 250.4(A)(1) and NEC 625.54, grounding is essential for all electrical installations, including EV chargers. Avoid using this setup in new installations.'
Grounding for the panel itself: An Earth Conductor connects the Ground Busbar to a Ground Rod and then to Ground/Earth.
The Electric Vehicle Geek logo is in the bottom left corner.

 

9Expert Score
For 240V 40A Level 2 EV charger installations—especially using a Mustart 40 Amp EV Charger or other 9.60 kW EV chargers—the UBITBA250 is a dependable, code-compliant solution. We tested it in real-world conditions, and it performed exactly as expected: solid, safe, and stable. It’s the go-to 50A breaker for anyone working with Challenger Type-A panels in need of EV-ready power.
Features
8.5
Real World Usage
9.5
Materials
9
Durability
8.5
Craftsmanship
9
Design
9
Monetary Value
9
Product Value
9
Brand Reputation
8.5
Expert Valuation
9.5
PROS
  • Narrow 1-inch width saves panel space.
  • Installs easily in Challenger Type A panels.
  • Supports 240V 40A Level 2 EV chargers.
  • New and UL-listed.
  • 10,000 AIC rating.
CONS
  • Only fits Challenger Type A panels.

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