Square D QO Series 3-Phase Loa...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$485.54
Square D QO Series 3-Phase Load Center, Fixed Main Lugs, NEMA 3R Enclosure

Square D QO Series 3-Phase Load Center, Fixed Main Lugs, NEMA 3R Enclosure

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Model: QO320L125GRB

In Stock (leaves warehouse same day if ordered before 3pm ET)

$485.54
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Square D QO Series 3-Phase Load Center, Fixed Main Lugs, NEMA 3R Enclosure

The Square D QO Series 3-Phase Load Center is built for dependable power distribution in commercial and industrial applications. This configuration offers 20 spaces and 20 circuits with 125A fixed main lugs, housed in a NEMA 3R weatherproof enclosure with a factory-installed ground bar. Designed to accept QO breakers, ground fault interrupters, arc fault interrupters, and surge arresters, it delivers flexible, UL Listed protection for demanding electrical systems.

Key Features

  • Panel Configuration: 20 spaces and 20 circuits with 125A fixed main lugs for reliable circuit distribution.
  • Durable Construction: Welded galvannealed steel enclosure with a baked enamel gray finish for corrosion resistance and long service life.
  • Busbar Material: Tin-plated copper busbar for secure, long-lasting electrical connections.
  • Wire Range: Main lugs accept AWG 6 through AWG 2/0 aluminum/copper conductors, tightened to 50 lb.in torque.
  • Environmental Rating: NEMA 3R weatherproof enclosure rated for outdoor and wet-location installations, with an ambient operating range of -5°C to 40°C.
  • Grounding: Includes a factory-installed ground bar for equipment grounding connections.
  • Phase Configuration: Supports 3-phase, 3-wire or 4-wire distribution setups.
  • Breaker Compatibility: Accepts QO breakers, ground fault interrupters, arc fault interrupters, and surge arresters for expanded protection options.

Certifications & Compliance

  • UL Listed
  • NEMA 3R Weatherproof Rated
  • RoHS EU Compliant
  • Mercury Free
  • Toxic Heavy Metal Free

Technical Specifications

  • Range Of Product: QO
  • Number Of Spaces: 20
  • Warranty: 18 months
  • Enclosure Material: welded galvannealed steel
  • Mercury Free: Yes
  • Toxic Heavy Metal Free: Yes

Typical Applications

  • Commercial and Industrial Electrical Distribution
  • Outdoor and Wet-Location Panel Installations
  • 3-Phase Power Distribution Systems
  • Renovation and New Construction Electrical Upgrades
  • Panelboard Replacement and Service Upgrades

Why Square D?

Square D QO load centers combine a welded galvannealed steel enclosure, tin-plated copper busbar, and baked enamel finish with UL Listed performance for code-compliant reliability. Built to accept a full range of QO breakers, ground fault and arc fault interrupters, and surge arresters, this load center gives electrical professionals the flexibility to configure robust, long-lasting protection for commercial 3-phase systems.

Manufacturer Resources

Product Specs

Product Type:
Load Center
Configuration:
NEMA 3R Enclosure
Amperage Rating:
125A
Listing:
UL Listed
Series:
QO
Product Material:
Galvannealed Steel
Product Color:
Baked Enamel Gray
Department:
Electrical
Product Group:
Power Distribution
Product Subgroup:
Panelboards & Load Centers
Product Width:
14.76 in
Country Of Origin:
United States
Product Height:
22.05 in

Square D QO320L125GRB – Frequently Asked Questions

1) Can the Square D QO320L125GRB load center be mounted outdoors?
Yes. The QO320L125GRB comes in a NEMA 3R weatherproof enclosure rated for outdoor and wet-location installs, with an ambient operating range of -5C to 40C. The housing is welded galvannealed steel with a baked enamel gray finish for corrosion resistance. If you are mounting it in a conditioned indoor electrical room, a NEMA 1 panel is the cheaper choice, but 3R is what you want on an exterior wall or in an unheated space.
2) Does this Square D QO panel have a main breaker or is it main lugs only?
Main lugs only. The QO320L125GRB uses 125A fixed main lugs, so overcurrent protection has to come from upstream, typically the main breaker in the service equipment feeding it. If code requires a disconnect at the panel, specify a main breaker load center instead.
3) How many circuits does the QO320L125GRB hold, and can I use tandem breakers to get more?
20 spaces and 20 circuits. The count of spaces and circuits is the same here, which means the panel is not rated to accept tandem or twin breakers for additional poles. Plan your circuit schedule around 20 poles, and step up to a larger load center if you need more.
4) Is the Square D QO320L125GRB a 3-phase panel, and does it work on a 4-wire wye system?
It is a 3-phase load center and supports either 3-wire (delta) or 4-wire (wye) distribution. On a 4-wire wye you land the neutral and use the factory-installed ground bar for equipment grounds. On a 3-wire delta the neutral bar goes unused.
5) Which breakers fit a Square D QO load center?
QO breakers, and that includes QO ground fault (GFCI) breakers, arc fault (AFCI) breakers, and QO surge arresters that occupy breaker spaces. Homeline breakers do not fit a QO panel and neither do other brands' plug-on breakers, so buy QO for every position.
6) What is the closest alternative to the Square D QO320L125GRB if I need a higher-amperage 3-phase outdoor main lug panel?
The Square D QO320L125GRB is a 125A main lug 3-phase load center in a NEMA 3R enclosure. If the service calls for more capacity, the ABB TL24415R is a main lug only load center rated 150A, 3-phase 4-wire 208Y/120V, also in a NEMA 3R enclosure. Both are main lug designs, so overcurrent protection is upstream in either case, but the ABB is specified for a 208Y/120V 4-wire system while the Square D QO accepts 3-phase 3-wire or 4-wire distribution and is built around QO breakers, ground fault and arc fault interrupters, and surge arresters.
7) Can I use an ABB ReliaHome load center instead of the Square D QO 3-phase panel outdoors?
Only if the application is single-phase residential-style distribution. The ABB ReliaHome is a plug-on neutral load center in a NEMA 3R aluminum enclosure. The Square D QO320L125GRB is a 3-phase, 125A main lug panel in a welded galvannealed steel NEMA 3R enclosure with a tin-plated copper busbar and factory-installed ground bar, supporting 3-phase 3-wire or 4-wire systems. For a commercial 3-phase feed, the ReliaHome is not a substitute; the ABB TL24415R, a 150A 3-phase 4-wire 208Y/120V main lug panel in NEMA 3R, is the closer match on phase configuration.
8) Do I need to buy a ground bar separately for this load center?
No. A ground bar is factory-installed in the QO320L125GRB, so equipment grounding conductors have a landing point out of the box. That saves an accessory kit on the takeoff, which matters when you are ordering a dozen panels for a job.
9) Copper or aluminum bus in the Square D QO320L125GRB?
Tin-plated copper. The plating resists oxidation at the breaker stabs, which is the connection that gives trouble over time in an outdoor panel where the enclosure sees temperature swings and condensation.
10) Is the Square D QO320L125GRB UL Listed?
Yes, it carries a UL Listing, along with the NEMA 3R weatherproof rating. It is also RoHS EU compliant, mercury free, and free of toxic heavy metals, which is what institutional and government specs usually want documented.
11) Can I use this QO panel for single-phase service?
The QO320L125GRB is built as a 3-phase load center. On a single-phase 120/240V service you would only be energizing two of the three bus phases, leaving a full leg of spaces dead. For single-phase work, order a single-phase QO load center instead so you get full use of all 20 positions.
12) What is the difference in enclosure construction between the Square D QO320L125GRB and the ABB ReliaHome NEMA 3R panel?
Both carry a NEMA 3R rating for outdoor and wet-location mounting, but the materials differ. The Square D QO320L125GRB uses a welded galvannealed steel enclosure with a baked enamel gray finish. The ABB ReliaHome load center uses an aluminum NEMA 3R enclosure. Steel with a baked enamel finish and aluminum are both used outdoors; the choice usually comes down to site corrosion conditions and the mounting method your installation calls for.
13) I have a NEMA 3R aluminum panel now, is the Square D a suitable replacement?
Enclosure metal differs. The Square D QO320L125GRB is welded galvannealed steel with a baked enamel gray finish, while the ABB ReliaHome NEMA 3R load center uses an aluminum enclosure. Aluminum is favored in coastal or high-salt environments; galvannealed steel with baked enamel is the standard commercial choice elsewhere. Either way, breakers do not carry over between the two, so a swap means repopulating the panel.
How fast can I get the Square D QO320L125GRB 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 QO320L125GRB come with a warranty?
Absolutely. The Square D QO320L125GRB 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 QO320L125GRB?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
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