Square D QO Main Breaker, Bolt...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$115.64
Square D QO Main Breaker, Bolt-On, 120/240VAC

Square D QO Main Breaker, Bolt-On, 120/240VAC

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Model: QOM50VH

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

$115.64
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Square D QO Main Breaker, Bolt-On, 120/240VAC

The Square D QO Main Breaker is a thermal magnetic circuit breaker engineered to provide overcurrent protection and switching for QO and Homeline load centers. Rated for 120/240 V AC operation and designed for bolt-on mounting, this breaker features an over-center, trip-free toggle mechanism with quick-make, quick-break action for dependable performance on ac and dc systems. It is UL Listed and CSA certified, making it a trusted choice as a main breaker for residential and light commercial electrical panels where consistent, code-compliant circuit protection is required.

Key Features

  • Trip-Free Toggle Mechanism: Over-center, quick-make, quick-break toggle design delivers positive, reliable switching action independent of handle position, helping prevent nuisance operation.
  • Bolt-On Mounting: Secure bolt-on connection for firm, vibration-resistant attachment to compatible QO and Homeline load centers.
  • Rated Operational Voltage: 120/240 V AC rating supports standard residential and light commercial branch circuit and main service configurations.
  • Wire Range Compatibility: Accepts AWG 4...AWG 2/0 aluminum/copper conductors with a tightening torque of 6-6 N.m, 4-65 mm² (AWG 12...AWG 2/0), simplifying field termination.
  • Overcurrent Protection: Thermal magnetic trip elements protect ac and dc systems from overload and short-circuit conditions, functioning as the main breaker for the load center.
  • Mercury-Free Construction: Manufactured without mercury for safer handling, installation, and disposal.
  • Accessory Compatible: Designed to work with a range of Square D QO accessories, including handle locks, alarm switches, and auxiliary trip devices, for expanded panel functionality.

Certifications & Compliance

  • UL Listed
  • CSA Certified
  • RoHS EU Compliant with Exemptions

Technical Specifications

  • Warranty: 18 months
  • Poles Description: 2P
  • Range Of Product: QO
  • Mercury Free: Yes
  • Packaging: 1 ea

Typical Applications

  • Residential and Light Commercial Load Centers
  • QO and Homeline Load Center Systems
  • Main Service Disconnect Applications
  • Overcurrent Protection for AC and DC Systems
  • Panelboard and Load Center Renovation or New Construction
  • Electrical Service Upgrades and Panel Replacements

Why Square D?

Square D engineers the QO Main Breaker with a proven trip-free toggle mechanism and secure bolt-on mounting for dependable, code-compliant overcurrent protection. Backed by an 18-month warranty and certified UL Listed and CSA, this breaker is built for electricians and contractors who need reliable, consistent performance from the main breaker in QO and Homeline load centers, whether for new construction or panel upgrades.

Manufacturer Resources

Product Specs

Product Type:
Circuit Breaker
Voltage Rating:
120/240V
Connection Type:
Bolt-On
Series:
QO
Listing:
UL Listed
Standards:
CSA
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Circuit Breakers
Product Depth:
5 in
Product Width:
3.46 in
Product Height:
5.08 in
Phase:
1 Phase

Square D QOM50VH – Frequently Asked Questions

1) Will the Square D QOM50VH main breaker fit a Homeline load center, or only QO panels?
The QOM50VH is built as a main breaker for both QO and Homeline load centers. It mounts bolt-on, not plug-on, so the panel interior has to be drilled and tapped for a bolt-on main. If your load center interior only accepts a plug-on main, this is the wrong mounting style for it.
2) What wire size can I land on this QO main breaker, and what torque do the lugs take?
The lugs accept AWG 4 through AWG 2/0 aluminum or copper conductors, with a tightening torque of 6-6 N.m across the 4-65 mm2 (AWG 12 to AWG 2/0) range. For a 50A single-phase service that puts typical copper or aluminum service entrance conductors well inside the range, and the dual-rated lugs mean you don't need a separate AL/CU adapter.
3) Is the Square D QOM50VH a two-pole breaker and will it work on 120/240V single phase?
Two-pole, rated 120/240 V AC, single phase. That covers a standard residential or light commercial service where you need both hot legs switched and protected at the main. It is not a three-phase device.
4) Is this breaker UL Listed and CSA certified for inspection on a service upgrade?
It is UL Listed and CSA certified, and RoHS EU compliant with exemptions. That is what an inspector looks for on a main service disconnect in a residential or light commercial panel.
5) Is the Eaton BAB1010 bolt-on breaker an equivalent to the Square D QOM50VH main breaker?
Both are bolt-on thermal-magnetic breakers, but they are not interchangeable. The QOM50VH is a Square D QO series two-pole main breaker rated 120/240 V AC for QO and Homeline load centers. The Eaton BAB1010 is a BAB series Quicklag thermal-magnetic bolt-on breaker, which mounts in Eaton BAB-compatible panelboards. Bolt-on breakers are keyed to their own manufacturer's bus and interior, so match the breaker to the panel brand rather than to the mounting style alone.
6) I need a three-pole breaker for a 3-phase panel instead of the QOM50VH. What should I look at?
The Square D QOM50VH is a single-phase, two-pole breaker rated 120/240 V AC, so it will not serve a three-phase application. For three-pole protection, the Eaton BAB-302 Quicklag is a three-pole thermal-magnetic breaker rated 240 V, and the ABB A2A150TT is a three-pole molded case breaker in the A2 series. Confirm the panel or enclosure the breaker will land in, since molded case and plug-in style breakers use different interiors.
7) Can I use an ABB ST200M miniature circuit breaker in place of a Square D QO main breaker?
No. The ABB ST200M is a C-curve miniature circuit breaker certified to UL1077, which covers supplementary protectors rather than branch and main overcurrent devices. The Square D QOM50VH is a UL Listed, CSA certified main breaker intended as the main service disconnect in QO and Homeline load centers. Use a UL Listed breaker where the device serves as the main or branch protection in a load center.
8) How much room do I need in the panel for this bolt-on main breaker?
Plan on 5.08 x 3.46 x 5 inches for the breaker body (height, width, depth as published). Check that against the main breaker pocket in the load center interior before you commit, especially on a retrofit where the existing main was a different frame.
9) Bussmann CBC breakers came up when I searched circuit breakers. Are those an alternative to the Square D QOM50VH?
They serve a different system entirely. The Bussmann CBC series is a Type I automotive circuit breaker rated 14 V DC, and the CBC-B version adds a waterproof stud terminal for vehicle and equipment wiring. The Square D QOM50VH is a 120/240 V AC, single-phase main breaker for QO and Homeline load centers. Automotive breakers are not a substitute in a building load center.
10) What would I use instead of the Square D QO main breaker for a large three-phase feeder with field-adjustable trip settings?
The QOM50VH is a fixed thermal-magnetic two-pole breaker for 120/240 V AC load centers. For a heavier three-phase feeder, the Eaton Series C K-Frame 6602C72G67 is a 400 A three-pole breaker supplied with an interchangeable rating plug, which lets the trip rating be set at installation. The ABB XT4 kit MBB33 and XT5 kit MBM334 are also three-pole molded case breaker assemblies. These are molded case devices and mount in switchboard or enclosure applications rather than in a QO load center interior.
11) What kind of trip unit does this use, electronic or thermal magnetic?
Thermal magnetic. The trip elements respond to sustained overload thermally and to short circuits magnetically, and the over-center toggle is trip-free with quick-make, quick-break action, so the contacts operate independent of how slowly you move the handle. There is no electronic trip unit to set up.
12) Does the QOM50VH ship as a single breaker or in a multi-pack?
It is packaged one each, so one order line is one breaker. Country of origin is Mexico, and the breaker is manufactured mercury-free, which matters for disposal and handling policies on institutional jobs.
13) Does the Square D QOM50VH accept accessories the way the Eaton NZM undervoltage release works on molded case breakers?
The Square D QOM50VH is designed to work with Square D QO accessories including handle locks, alarm switches, and auxiliary trip devices. The Eaton 10250T-GR is an undervoltage release built for Eaton NZM series molded case breakers, so it is not a fit for a QO main breaker. Stay within the breaker's own accessory family when adding trip or signaling devices.
How fast can I get the Square D QOM50VH 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 QOM50VH come with a warranty?
Absolutely. The Square D QOM50VH 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 QOM50VH?
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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