FNQ-R-4/10 TIME DELAY FUSE BUSSMANN

FNQ-R-4/10 TIME DELAY FUSE BUSSMANN

FNQ-R-4/10 TIME DELAY FUSE BUSSMANN – Industrial 0.4A 600VAC Class CC Current-Limiting Fuse

The FNQ-R-4/10 TIME DELAY FUSE BUSSMANN (Model FNQ-R-4/10) is a high-precision, 0.4-amp (4/10A) dual-element time-delay Class CC rejection-type fuse manufactured by Eaton’s Bussmann series. Engineered specifically for protecting sensitive low-amperage inductive circuits, this 600VAC LIMITRON™ current-limiting fuse provides superior electrical protection for small industrial control transformers, solenoids, relays, and automation equipment.

Designed to handle high temporary inrush currents without nuisance tripping, the FNQ-R-4/10 TIME DELAY FUSE BUSSMANN delivers a minimum 12-second time-delay at 200% of its rated current. This dual-element design allows harmless startup magnetization and inductive surge currents to pass safely, while maintaining rapid current-limiting response times during destructive short-circuit fault conditions up to 200kA RMS Symmetrical at 600VAC. Its rejection-style body prevents lower-rated or non-Class CC fuses from being mistakenly installed into rejection fuse blocks, maintaining strict National Electrical Code (NEC®) safety compliance.

As shown in the image, the fuse features a high-durability white melamine body clearly labeled with “Bussmann LIMITRON™ CURRENT LIMITING TIME-DELAY CLASS CC FUSE FNQ-R-4/10 600Vac”, capped with nickel-plated bronze ferrule end caps featuring the physical Class CC rejection pin tip.

Key Features of the FNQ-R-4/10 TIME DELAY FUSE BUSSMANN

• Dual-Element Time-Delay Characteristic: Provides a minimum 12-second time-delay at 200% of rated load, absorbing momentary inrush current spikes without blowing unexpectedly.

• Low-Amperage Precision Protection: Rated at 0.4 Amps (4/10A), offering accurate overcurrent protection for low-power control components and delicate instruments.

• Class CC Rejection Feature: Built with a grooved rejection end-cap pin that physically prevents the insertion of non-rejection or lower-interrupting-rated supplementary fuses into Class CC fuse holders.

• High 200kA Interrupting Rating: Rated for 200kA RMS Symmetrical at 600VAC, ensuring high-level branch and component circuit protection under maximum short-circuit conditions.

• Extreme Current Limitation: Restricts thermal and magnetic energy let-through under fault conditions, shielding downstream panel components from physical damage.

• Durable Melamine Construction: Built with a high-strength melamine tube and nickel-plated end caps for high thermal resistance and corrosion protection in harsh industrial environments.

Common Applications and Practical Usage

The precision inductive protection of the FNQ-R-4/10 TIME DELAY FUSE BUSSMANN makes it essential across industrial automation and electrical control systems:

• Control Transformer Primary Protection: Ideal for protecting the primary side of low-VA industrial control transformers subjected to high magnetizing startup inrushes.

• Solenoid & Magnetic Coil Protection: Shields small solenoids, magnetic valves, and actuator coils from sustained overloads while tolerating high initial pull-in currents.

• Industrial Automation & PLCs: Guards delicate input/output modules, sensing relays, and power supply feed lines inside industrial control panels (ICPs).

• HVAC & Commercial Controls: Used in commercial HVAC control units, burner ignition systems, and automated damper controls.

Technical Specifications

The core electrical, physical, and compliance parameters for the FNQ-R-4/10 TIME DELAY FUSE BUSSMANN are detailed below:

Operating Guidelines and Usage Tips

SAFETY NOTICE: Always isolate main power sources and verify de-energized circuits using a calibrated multimeter before inspecting or replacing power fuses.

• Transformer Sizing: Size the primary fuse between 125% and 250% of the transformer’s primary full-load amps (FLA) per NEC Article 450 guidelines.

• Holder Compatibility: Pair exclusively with UL Class CC rejection fuse blocks or modular DIN-rail holders (such as the Bussmann CHCC series) to utilize the physical safety keying feature.