Siemens BQD140 - 40 A, 277 V, 1-Pole Bolt-On Circuit Breaker | AmpState

The Siemens BQD140 is a trusted choice for dependable branch circuit protection in panelboards and load centers. This 40A, 277V, 1-pole bolt-on molded case circuit breaker pairs robust construction with precise protection, making it a reliable backbone for commercial and light industrial electrical systems as well as residential applications where single-phase circuits matter most.

Why the Siemens BQD140 stands out

• Secure bolt-on mounting delivers a rigid, vibration‑resistant bus connection that stays solid through constant operation and environment changes.
• Thermal-magnetic trip unit provides stable, repeatable protection performance against both overcurrent and short circuits, helping prevent nuisance trips and equipment damage.
• OEM-compatible design is built to work with matching Siemens OEM load centers and panelboards for a seamless, reliable electrical distribution system.
• Versatile application suitable for residential, commercial, and light industrial settings—perfect for controlling single-phase branch circuits in a variety of environments.

Use cases and applications

Designed for single-pole protection, the BQD140 shines in scenarios where 277V circuits drive important equipment and lighting. Ideal uses include:

• Commercial lighting panels in offices, retail spaces, and schools that run on 277V single-phase distribution.
• Load centers in small to mid-size commercial systems where space is at a premium and dependable protection is critical.
• Residential subpanels or mixed-use installations that require a reliable 40A, single-pole breaker with solid bus connections.
• Light industrial applications where vibration resistance and secure mounting improve long-term reliability.

Technical snapshot

• Manufacturer: Siemens
• Part Number: BQD140
• Type: Thermal-magnetic molded case circuit breaker
• Amperage: 40A
• Voltage: 277V
• Number of Poles: 1
• Mounting Style: Bolt-on
• Application: Branch circuit overcurrent and short-circuit protection

Installation and compatibility tips

To maximize performance, pair the BQD140 with matching Siemens OEM load centers and panelboards designed for bolt-on breakers. The bolt-on mounting helps maintain a solid electrical connection in environments subject to vibration or movement, contributing to long-term reliability. Always follow local electrical codes and manufacturer installation guidelines to ensure safe, compliant operation.

Whether upgrading an existing panel or configuring a new installation, the Siemens BQD140 delivers precise protection for critical single-phase circuits, combining robust construction with dependable protection you can trust.