Engineered for commercial applications, the Square D QOU315-1021 delivers robust overcurrent protection for AC and DC systems. This 15-amp miniature breaker ensures reliable performance in demanding environments. Its versatile unit-mount design allows for seamless integration into DIN rail systems, OEM enclosures, and control panels. A factory-installed shunt trip enables remote tripping capabilities. It also features a Visi-Trip indicator for rapid fault identification.
What does the -1021 suffix indicate on the QOU3151021 circuit breaker?
The -1021 suffix designates a factory-installed 120, 208, or 240 VAC shunt trip. This accessory allows for remote tripping of the circuit breaker via an external control signal.
How does the factory-installed shunt trip affect the physical footprint of the QOU3151021?
The shunt trip accessory occupies one additional pole space. Because this is a 3-pole breaker, the total width will be equivalent to a 4-pole device, requiring extra space on the DIN rail or inside the OEM enclosure.
Can I add an auxiliary switch or bell alarm to the QOU3151021 in the field?
No. Square D QOU miniature circuit breakers accept only one accessory per breaker. Since the 120/240 VAC shunt trip is factory-installed, no additional electrical accessories can be added to this unit.
What wire sizes are accepted by the shunt trip terminals on this breaker?
The terminals for the factory-installed shunt trip accept up to two 14-12 AWG copper (Cu) wires. The hot and neutral control wires can be connected to either terminal on the accessory.
Is the QOU3151021 compatible with standard QO or NQ load centers?
No. QOU series breakers are unit-mount devices designed for DIN rail systems, OEM control panels, and standalone enclosures. They do not plug into or bolt onto standard QO or QOB panelboard busbars.
How is the QOU3151021 mounted in a control panel?
This unit-mount breaker can be installed on a standard 35mm DIN rail, flush-mounted, or surface-mounted using the appropriate mounting feet. It features reversible box lugs for flexible line and load wiring.
Does the QOU3151021 feature a visual trip indicator?
Yes, it includes the Square D Visi-Trip indicator. When the breaker trips due to an overcurrent, short circuit, or is tripped remotely via the shunt trip, a red indicator appears to help quickly identify the faulted circuit.
Can the QOU3151021 be reverse fed?
Yes, QOU miniature circuit breakers are suitable for reverse feeding. The box lugs are reversible, allowing line connections to be made at either the top or bottom terminals without affecting the trip mechanism.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 106 reviews.
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Rated 5.0 out of 5 stars
Based on 106 reviews
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Reviews Summary
Generated by AI from 99 most recent customer reviews
Last updated 5/14/26
Customers say these circuit breakers function properly and arrive quickly. Many reviews highlight fast shipping, competitive pricing, and reliable product condition upon arrival. Users appreciate the wide selection, including hard-to-find models, and note the breakers work as expected for various applications. Common feedback addresses quick order processing and easy website navigation. Most customers report satisfaction with value and delivery speed, with many indicating they will purchase again.
Square D QOU260 - 60A 2 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
9/7/26
Good thing
i recommend this for you
RG
Robert G.
Verified Buyer
Reviewing
Square D QOU340 - 40A 3 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
9/3/26
Circuit breakers
I appreciate the fact that you had these in stock. my Square D distributor does not seem to stock these anymore and it takes a couple weeks to get. your pricing is inline with theirs.
TH
Tiffany H.
Verified Buyer
Reviewing
Square D QOU115 - 15A 1 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/28/26
Will use Super Breakers again
Arrived in a timely manner. Exactly what we needed for a job.
CS
Cary S.
Verified Buyer
Reviewing
Square D QOU250 - 50A 2 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/12/26
Just what I ordered
Just what I needed for dock pedestal
MH
Mark H.
Verified Buyer
Reviewing
Square D QOU250VH - 50A 2 Pole Miniature Circuit Breaker
I recommend this product
Rated 5 out of 5 stars
8/11/26
Square D QOU250VH - 50A 2 Pole Miniature Circuit Breaker