Bussmann FNQ 20 Amp fuse 500 V

Bussmann FNQ 20 Amp fuse – 500 V time-delay protection for motor circuits and transformers

The Bussmann FNQ 20 Amp fuse is an industry-standard, midget-sized time-delay cartridge fuse rated for 500 VAC and designed to protect motor control transformers, branch circuits, control equipment, and lighting systems from overloads and short circuits. This fuse meets the needs of demanding industrial, commercial, and residential applications, offering reliable protection with minimized downtime.

Why choose the Bussmann FNQ 20 Amp fuse?

This Bussmann FNQ 20 Amp fuse features a dual-element, time-delay design, allowing it to tolerate short-duration surge currents—up to 200% of its rated current—for at least 10 seconds. This is ideal for protecting motors and transformers during startup while still responding quickly to dangerous overloads. The current-limiting feature helps reduce let-through current during short circuits, minimizing damage to downstream components like turbines and wiring.

Key specifications

• Voltage rating: 500 VAC

• Current rating: 20 Amps

• Time-delay performance: Withstands 200% surge current for a specified time

• Interrupt rating: 10 kA at 500 V AC ([turn0search0], [turn0search3], [turn0search4])

• Size: 1.5 inches length × 0.41 inches diameter (13/32″ × 1½″) ([turn0search4], [turn0search8])

• Body material: Fiber tube with nickel‑plated brass end caps ([turn0search4], [turn0search14])

• Fuse ends: Ferrule‑end × ferrule‑end cartridge

• Agency approvals: UL 248‑14, CSA C22.2 No. 248.14, CE; RoHS compliant ([turn0search14])

• Interrupt rating: 10 kA @ 500 VAC — suitable for supplemental protection of control circuits

Ideal applications

• Motor control equipment: provides surge tolerance at startup

• Lighting and control circuits: reliable time-delay protection

• Transformers and HVAC systems: prevents nuisance trips during inrush

• Panelboards and switchboards: safety-grade protection for machine circuits

• Industrial machinery and embedded systems

This fuse’s compact size (midget format) makes it a versatile choice for enclosed fuse holders in tight spaces.

Installation and compatibility

The Bussmann FNQ 20 Amp fuse fits any ferrule-style fuse holder compatible with 13/32″ × 1½″ midget fuses. Installation is straightforward: snap into the holder, secured by clip-ended ferrules. Ensure proper panel wiring and torque per installer standards to maintain system integrity.

Safety and performance

With UL and CSA certifications, the Bussmann FNQ 20 Amp fuse meets NFPA, UL, and NEC code requirements. The dual-element design minimizes nuisance overcurrent interruptions while delivering dependable protection against hazardous conditions.

Dimensions and packaging

• Length: 1.50 inches (±0.03″)

• Diameter: 0.41 inches (±0.008″)

• Weight: ~0.02 pounds (9 g) per fuse ([turn0search8])

• Available in individual and bulk boxes (10-pack standard)

Why Bussmann?

Bussmann (by Eaton) is one of the world’s leading manufacturers of circuit protection devices. The FNQ 20 Amp fuse offers industry-leading performance and durability at an affordable price, making it a top choice for electricians and maintenance professionals.