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Square D QO340GFI GFCI Miniature Circuit Breaker
- 40A
- 3 Pole
- Plug-On
Square D
QO340GFI
GFCI Miniature Circuit Breaker
Brand
Square D
SKU
QO340GFI
Quantity
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Square D QO340GFI - 40A GFCI Miniature Circuit Breaker
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Quantity
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Description
Providing robust 40A capacity, this three-pole GFCI device delivers critical 6mA personnel protection for 208Y/120V commercial systems. It incorporates a pigtail neutral wire and the highly visible Visi-Trip flag to quickly identify tripped circuits during maintenance. Compatible with QO load centers, NQ, and legacy NQOD panelboards, the unit utilizes a standard plug-on mounting style. Upgraded box lug terminals accommodate larger 14-6 AWG copper or 12-4 AWG aluminum wiring.Specifications
| Brand | Square D |
|---|---|
| Series | QO |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 208Y/120VAC |
| Phase | 3 |
| AIC Rating | 10kA @ 208Y/120VAC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | QO Load Centers, NQ Panelboards, NQOD Panelboards |
| Wire Gauge | 14-6 AWG (Cu), 12-4 AWG (Al) |
| Max Wire | 6 AWG (Cu), 4 AWG (Al) |
| Min Wire | 14 AWG (Cu), 12 AWG (Al) |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LIG |
| Trip Function | Long-Time, Instantaneous, Ground Fault |
| Trip Adjustability | Fixed |
| Special Classification | GFCI |
|---|---|
| Available Options | Padlock Attachment |
| Accessories | Pigtail Neutral |
| Standards | CSA C22.2 No. 5, UL 489, UL 943 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator |
Product FAQs
7 answersCan I install the QO340GFI in a Square D Homeline load center?
No. QO series breakers are not interchangeable with Homeline panels. This breaker is designed exclusively for Square D QO load centers, NQ panelboards, and NQOD panelboards.
How many panel spaces does this 3-pole breaker require?
The QO340GFI requires three standard 3/4-inch spaces in a compatible QO or NQ/NQOD panel.
How is the neutral connection made for the ground fault protection?
This breaker features a pigtail neutral. The coiled white wire must be connected directly to the panel's neutral bus bar for the GFCI circuitry to function correctly.
What type of electrical system is this breaker designed for?
As a 3-pole breaker rated for 208Y/120VAC, it is intended for use in 3-phase, 4-wire grounded systems.
What is the ground fault trip sensitivity for this breaker?
The QO340GFI provides Class A ground fault protection, meaning it is designed to trip when it detects a ground fault current of 6 mA or higher to protect personnel.
Does this breaker provide a visual indication if it trips?
Yes, it features Square D's Visi-Trip indicator. When the breaker trips due to an overcurrent or ground fault, a highly visible red indicator appears in the window to help quickly identify the tripped circuit.
Is there a bolt-on equivalent for this breaker?
Yes, for applications requiring a bolt-on connection, such as in NQOB panelboards, the equivalent model is the QOB340GFI.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 285 reviews.
Reviews Summary
Generated by AI from 100 most recent customer reviews
Last updated 6/13/26
Customers say these circuit breakers arrive quickly and work as described. Fast shipping and competitive pricing are frequently mentioned, with many noting same-day or next-day delivery. Users appreciate the wide inventory, particularly for hard-to-find older-style models unavailable locally. The products function reliably and arrive in good condition. Most customers report straightforward ordering and positive interactions. However, some experienced delivery delays or received incorrect items requiring reordering. A few noted concerns about condition upon arrival or customer service responsiveness.
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Rating
285 reviews
- GCGerard C.Verified BuyerReviewingSquare D QO130GFI - 30A GFCI Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/21/26Great !
I could not find the breaker in hardwood stores. Superbreakers took car of it in a week.
- RHRoy H.Verified BuyerReviewingSquare D QO280 - 80A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/17/26Square D QO280 - 80A 2 Pole Miniature Circuit Breaker
Exactly as described
- KWKevin W.Verified BuyerReviewingSquare D QO120 - 20A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/15/26Great Price
Brand spanking new!
- CEchristopher e.Verified BuyerReviewingSquare D QO115PDF - 15A Dual Function Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/11/26My breakers
Had a hard time locating these breakers locally, when I did find 1 they wanted to charge me triple what superbreakers charged. Items delivered exactly when they said they would, were exactly what I ordered. Appreciated the ease of ordering, definitely my go to from this point on
- JCJerry C.Verified BuyerReviewingSquare D QO250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/8/26Great quality
No issues