Square D FJA140403 Molded Case Circuit Breaker
- 40A
- 1 Pole
- I-Line
Quantity
Square D FJA140403 - 40A 1 Pole Molded Case Circuit Breaker
New
Quantity
Description
Part of Square D's legacy F-Frame series, the FJA140403 delivers robust overcurrent protection for commercial and industrial applications. It is specifically designed to install into I-Line panelboards and switchboards, utilizing a plug-on mounting style for efficient setup. Rated at 65 kAIC at 277VAC, this 40-amp molded case circuit breaker features fixed thermal-magnetic trip units (LI) and a Phase B connection. Note that this unit is replaced by the HJA260403, which requires two pole spaces.Specifications
| Brand | Square D |
|---|---|
| Part Number | FJA140403 |
| Series | FJA |
| Amperage | 40A |
| Poles | 1 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 277VAC, 125VDC |
| Phase | 1 |
| AIC Rating | 65kA @ 240VAC, 65kA @ 277VAC, 10kA @ 125VDC |
| Frame Type | FJA |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards and Switchboards |
| Wire Gauge | 14-1/0 AWG (Cu/Al) |
| Max Wire | 1/0 AWG |
| Min Wire | 14 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Alarm Switch, Undervoltage Release, Padlock Attachment |
|---|---|
| Accessories | Phase B Connection (Factory Configured) |
| Standards | UL 489, CSA C22.2 No. 5, NEMA AB 1, IEC 60947-2 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, High Interrupting Capacity |
Product FAQs
7 answersWhat panelboards accept the FJA140403?
This breaker is designed exclusively for Square D I-Line panelboards and switchboards. It features the I-Line plug-on mounting style, which engages directly with the bus stack.
How does the I-Line mounting system work for this breaker?
The FJA140403 uses a plug-on design where the breaker jaws push directly onto the I-Line bus stack. A mounting bracket secures the breaker in place, allowing for fast installation without bolting directly to the busbars.
Can this 1-pole breaker be used in a 480V system?
Yes, it is rated for 277VAC, making it suitable for 277V phase-to-neutral loads in a 480Y/277V solid-grounded wye system. It carries a 65kA interrupting rating at 277VAC.
Is this breaker suitable for DC applications?
Yes, the FJA140403 is rated for 125VDC applications and provides a 10kA interrupting capacity at that voltage.
What wire sizes and materials are accepted by the lugs?
The factory-installed lugs accept 14 AWG to 1/0 AWG copper or aluminum conductors. Ensure proper torque is applied per the manufacturer label instructions when terminating the wire.
What does the LI trip function indicate?
The LI designation indicates the breaker uses thermal magnetic protection with a fixed Long-Time trip for overload protection and a fixed Instantaneous trip for short-circuit protection.
Is the FJA frame a current production model?
F-frame breakers are legacy molded case circuit breakers. While newer installations often use PowerPact H-frame or J-frame breakers, I-Line F-frames like the FJA140403 are still sourced for maintaining and expanding existing panelboards.
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