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Square D
Starting at
$591.51
Square D QO 125A 3-Pole Lug Kit, Bolt-On Subfeed Breaker Accessory
The Square D QO lug kit is a mini circuit breaker accessory designed for 125A, 3-pole, bolt-on subfeed applications within QO load centers, occupying 3 spaces in the panelboard. Rated 240V AC and accepting AWG 12 through AWG 2/0 copper or aluminum conductors, this accessory is engineered for reliable overcurrent protection and switching performance. It is CSA certified and cURus listed, making it suitable for residential and light-commercial subfeed installations that demand code-compliant panelboard hardware.
Key Features
- Amperage Rating: 125A subfeed lug kit for QO panelboard applications.
- Configuration: 3-pole, bolt-on mounting, occupies 3 spaces in the load center.
- Voltage Rating: 240V AC operational voltage for standard residential and light-commercial systems.
- Wire Range: Accepts AWG 12 through AWG 2/0 copper or aluminum conductors for flexible feeder sizing.
- Operating Temperature: Rated for ambient operation from -5 °C to 40 °C.
- Product Range: Part of the Square D QO circuit breaker and accessory line.
Certifications & Compliance
- CSA Certified
- cURus Listed
Technical Specifications
- Range Of Product: QO
- Number Of Poles: 3
- Number Of Spaces: 3
- Warranty: 18 months
- Mercury Free: Yes
- Toxic Heavy Metal Free: Yes
- Country of Origin: Mexico
Typical Applications
- Residential and Light-Commercial Load Centers
- QO Panelboard Subfeed Installations
- Bolt-On Circuit Breaker Accessory Retrofits
- Panelboard and Load Center Wiring
- New Construction and Panel Upgrades
Why Square D?
Square D QO accessories are built for dependable, code-compliant performance in residential and light-commercial electrical systems. With CSA certification and cURus listing backing this 125A, 3-pole bolt-on subfeed lug kit, electrical professionals can install with confidence knowing the accessory meets recognized safety and construction standards for panelboard applications.
Manufacturer Resources
Product Specs
- Product Type:
- Lug Kit
- Voltage Rating:
- 240V
- Amperage Rating:
- 125A
- Configuration:
- 3-Pole Bolt-On
- Listing:
- cURus
- Standards:
- CSA
- Series:
- QO
- Department:
- Electrical
- Product Group:
- Wire Connectors & Terminals
- Product Subgroup:
- Terminal Blocks & Strips
- Product Depth:
- 2.31 in
- Product Height:
- 3.5 in
- Product Width:
- 2.241 in
- Number Of Poles:
- Three-pole
Square D QOB3125SL – Frequently Asked Questions
1) Will the Square D QOB3125SL subfeed lug kit fit a QO load center?
The QOB3125SL is built for Square D QO load centers and panelboards. It is a bolt-on mount, so the panel interior has to be the bolt-on type, not a plug-on QO interior. It takes up 3 spaces in the panel, so you need three adjacent open spaces where you want to land the subfeed.
2) What wire size can I land in the Square D 125A QO subfeed lug kit?
Each lug takes AWG 12 through 2/0, copper or aluminum. That covers typical 125A feeder sizing in either metal, so a 2/0 aluminum or a 1/0 copper subfeed both terminate without an adapter or reducing pin.
3) Is the QOB3125SL a circuit breaker or just lugs?
It's a lug kit, not a breaker. The QOB3125SL gives you a bolted set of 3-pole subfeed terminals rated 125A at 240V AC so you can feed a downstream panel from a QO load center. It provides no overcurrent protection of its own, so the feeder still has to be protected by a breaker ahead of it.
4) Can I use this 3-pole QO lug kit on a 208Y/120 three-phase panel?
Voltage rating is 240V AC, which covers 120/240V single phase and 208Y/120V three-phase systems. It is three-pole, so it will land all three phase conductors. Do not use it on 480V or 240/120 high-leg delta gear above its 240V rating.
5) Is the Square D QOB3125SL lug kit listed for inspection sign-off?
It is cURus listed and CSA certified, which covers both US and Canadian installations in residential and light-commercial panelboards. Country of origin is Mexico.
6) How much room does the 125A QO subfeed lug kit need inside the panel?
Published size is 3.5 in height, 2.241 in width, and 2.31 in depth. The depth matters most when you are working in a shallow surface-mount can with a cover, and the 2.241 in width is what spans the three breaker spaces it occupies.
7) Can I add the QOB3125SL to an existing QO panel as a retrofit?
Yes, it is intended for subfeed retrofits as well as new work, provided the panel is a QO bolt-on interior with three adjacent spaces free and the bus is rated for the added 125A subfeed load. It bolts to the bus the same way a QOB breaker does.
8) Can this QO lug kit be installed in an unheated garage or outdoor-rated enclosure?
Ambient rating is -5 C to 40 C. That rules out unconditioned spaces that drop below about 23 F, so for a cold-climate exterior or unheated outbuilding you need to confirm the enclosure interior stays inside that band.
How fast can I get the Square D QOB3125SL delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the
continental
U.S.
Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit,
reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Square D QOB3125SL come with a warranty?
Absolutely. The Square D QOB3125SL is backed by a manufacturer’s warranty.
For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Square D QOB3125SL?
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installation tips, and troubleshooting. Contact Us
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