Square D

Square D is an electrical equipment manufacturer founded in 1902, now a brand of Schneider Electric since 1991. Square D produces QO and Homeline load centers, circuit breakers, panelboards, safety switches, surge protection devices, and motor control equipment for residential, commercial, and industrial electrical applications. The QO circuit breaker introduced in 1955 became the industry standard for residential panel construction. Available through electrical and HVAC wholesale distributors including SupplyHouse.

Square D Product Lines

• QO Load Centers and Circuit Breakers: Professional-grade residential panels and breakers with Visi-Trip indicator.
• Homeline Load Centers and Breakers: Value-tier residential panels and circuit breakers.
• Commercial Panelboards and Breakers: QOB and QOP breakers for NQ, NF, and I-Line commercial panelboard systems.
• Safety Switches: Fusible and non-fusible disconnects for HVAC equipment and motor circuits.
• Surge Protection Devices: Whole-home and commercial transient voltage protection.
• Motor Control and Starters: Contactors and starters for commercial HVAC and industrial motor circuits.

Why Contractors Specify Square D

Square D QO is the most widely stocked residential circuit breaker in North America. Safety switches cover the amperage and voltage ratings required for most HVAC equipment disconnects. Broad availability through HVAC and electrical wholesale distribution.

How to Choose a Square D Product

Match the circuit breaker series to the panel brand and series already installed. For HVAC disconnects, select the safety switch based on equipment amperage, voltage, and whether fusible or non-fusible is specified by the equipment manufacturer.

Frequently Asked Questions

• QO vs. Homeline? QO is professional-grade for QO panels; Homeline is value-tier for Homeline panels; they are not interchangeable.
• Who owns Square D? Schneider Electric, since 1991.
• HVAC circuit breakers? Square D covers the single-pole, double-pole, and three-phase ratings required for residential and commercial HVAC circuits.
• When is a safety switch required? NEC requires a within-sight disconnect for HVAC equipment; size per the equipment installation instructions.
• Available at HVAC distributors? Yes, including SupplyHouse.