Overview
The Bussmann FNQ-R-3/4 is a Class CC time-delay, dual-element current-limiting fuse designed for advanced circuit and equipment protection in industrial and commercial applications. This cartridge-style fuse combines the reliability of Bussmann’s proven CC-Tron technology with a compact form factor and rejection-style design to prevent mismatched fuse installation.
Key Features
- Time-Delay (Slow-Blow) Design: Accommodates temporary inrush currents from control transformers and small motors without unwanted interruption
- Current-Limiting Technology: Restricts fault current to Class CC limits, reducing downstream equipment stress and secondary damage during short circuits
- Rejection-Style Fuse: Non-insertion design prevents installation of incorrect amperage ratings, reducing misapplication risk
- Dual-Element Construction: Melamine tube body with ferrule-end terminals for reliable performance and industry-standard mounting
- 200kA Interrupting Rating: Handles high fault currents safely at 600VAC branch circuit level
Technical Specifications
- Amperage Rating: 0.75A (3/4A)
- Voltage Rating: 600VAC
- Fuse Class: Class CC
- Type: Time Delay / Slow Blow
- Interrupting Rating: 200kA AC RMS Symmetrical
- Response Time: 12 seconds at 200% current
- Terminal Style: Ferrule End x Ferrule End
- Body Style: Cylindrical Cartridge
- Dimensions: 0.41″ diameter × 1.5″ length (10.3mm × 38.1mm)
- Weight: 0.32 oz per unit
- Series Designation: LIMITRON® FNQ-R
Typical Applications
- Control circuit transformer protection in motor control centers (MCCs)
- Low-voltage industrial control circuits requiring current limitation
- Small horsepower motor circuit branch protection
- Equipment protection in manufacturing, HVAC, and commercial electrical systems
- Applications requiring immunity to normal inrush surges with fast fault response
Compatibility & Replacements
Compatible With
- Class CC fuse holders and rejection-style fuse blocks
- Standard electrical control panels and distribution systems operating at 600VAC
- Control transformer circuits (primary and secondary protection)
- Industrial PLCs, drives, and control equipment using Class CC branch circuit protection
Replaces / Drop-In Replacement For
- FNQ-R.75, FNQ-R-0.75, FNQ-R 0.75A — Direct functional equivalents
- Cooper Bussmann FNQ-R-3/4 — Original manufacturer equivalent
- Eaton Bussmann FNQ-R-3/4 — Current Eaton-branded equivalent
Works With
- Certifications: UL Listed (Std. 248-4, Class CC, Guide JDDZ, File E4273); CSA Certified (Class 1422-01, File 53787); CE and RoHS Compliant
- Standards Compliance: All major electrical distribution and industrial automation standards supporting Class CC fuses
