Siemens BQD390 - 90 A, 480 V, 3-Pole Bolt-On Circuit Breaker | AmpState

Siemens BQD390 is a 3‑pole, 90 A bolt‑on molded case circuit breaker built to deliver dependable branch circuit overcurrent and short‑circuit protection in panelboards and loadcenters.

• Secure bolt‑on mounting creates a rigid, vibration‑resistant bus connection, helping maintain consistent electrical contact even in environments subject to mechanical movement or vibration.
• Thermal‑magnetic trip unit combines precise overload protection with instantaneous magnetic interruption for stable, repeatable response to varying loads and fault conditions.
• OEM‑grade compatibility is designed to integrate smoothly with matching Siemens OEM load centers and panelboards, ensuring a cohesive protection system without compatibility worries.
• 3‑phase, 480 V operation makes it ideal for commercial and light industrial distributions, safeguarding multiple circuits in a single device.
• Versatile for multiple sectors suitable for residential, commercial, and light industrial applications where robust 3‑pole protection is required.

Use cases and practical benefits:

• Protects branch circuits feeding motors, lighting, HVAC, and other heavy loads in 480 V, 3‑phase systems, helping prevent damage from overcurrent and short circuits.
• Thermal and magnetic coordination minimizes nuisance trips while delivering rapid protection during faults, reducing equipment downtime and maintenance costs.
• Bolt‑on design supports secure, long‑term mounting in panelboards and loadcenters, contributing to reliable service life in demanding installation environments.

Technical specifications

• Manufacturer: Siemens
• Part number: BQD390
• Type: Thermal‑magnetic molded case circuit breaker
• Amperage rating: 90 A
• Voltage rating: 480 V
• Number of poles: 3
• Mounting style: Bolt‑on
• Application: Branch circuit overcurrent and short‑circuit protection

Ideal for electrical professionals and facilities teams seeking a reliable, OEM‑aligned protective device for 480 V 3‑phase panelboards. The Siemens BQD390 delivers predictable protection, easy integration with Siemens load centers, and a durable design that stands up to ongoing service in residential, commercial, and light industrial settings.