FNQ-R-20 TIME DELAY FUSE BUSSMANN

FNQ-R-20 TIME DELAY FUSE BUSSMANN – Industrial 20A 600VAC Class CC Current-Limiting Fuse

The FNQ-R-20 TIME DELAY FUSE BUSSMANN (Model FNQ-R-20) is an industrial-grade, dual-element time-delay Class CC rejection-type fuse manufactured by Eaton’s Bussmann series. Engineered specifically for high-inrush inductive loads, this $20text{-amp}$ current-limiting fuse provides superior electrical protection for control transformers, solenoids, small motor branch circuits, and industrial control systems.

Unlike fast-acting fuses that blow under temporary current surges, the FNQ-R-20 TIME DELAY FUSE BUSSMANN features a minimum 12-second time-delay at $200%$ of its rated current. This allows harmless startup inrush currents to pass safely while maintaining rapid current-limiting clearing speeds during destructive short-circuit fault conditions up to $200text{kA RMS}$ Symmetrical at $600text{VAC}$ . Its rejection-style body ensures that lower-rated supplementary fuses cannot be mistakenly installed into Class CC fuse blocks, maintaining strict National Electrical Code (NEC®) safety compliance.

As shown in the image, the fuse features a high-durability white melamine body labeled with “Bussmann LIMITRON™ CURRENT LIMITING TIME-DELAY CLASS CC FUSE FNQ-R-20 600Vac 300Vdc”, capped with nickel-plated bronze ferrule end caps featuring the characteristic Class CC rejection pin tip.

Key Features of the FNQ-R-20 TIME DELAY FUSE BUSSMANN

Dual-Element Time-Delay Performance: Offers a minimum of $12text{ seconds}$ time-delay at $200%$ rated load, eliminating nuisance fuse openings caused by motor startup surges and transformer inrush currents.
Class CC Rejection Feature: Built with a grooved rejection end-cap pin that prevents the insertion of non-rejection or lower-interrupting-rated supplementary fuses into Class CC fuse blocks.
High $200text{kA}$ Interrupting Rating: Rated for $200text{kA RMS}$ Symmetrical at $600text{VAC}$ , ensuring high-level branch circuit protection under extreme fault conditions.
Advanced Current Limitation: Limits short-circuit peak let-through currents significantly, reducing mechanical thermal stress on downstream panel components.
Dual Voltage Compatibility: Rated for up to $600text{VAC}$ and $300text{VDC}$ systems for versatile deployment across AC and DC control circuits.
Durable Melamine Construction: Constructed with a high-strength melamine tube and nickel-plated end caps for high thermal stability and corrosion protection.

Common Applications and Practical Usage

The specialized inductive-load capability of the FNQ-R-20 TIME DELAY FUSE BUSSMANN makes it essential for heavy-duty industrial automation and control panels:

Control Transformer Protection: Ideal for protecting the primary side of industrial control transformers where startup magnetization inrush currents would blow fast-acting fuses.
Small Motor Branch Circuits: Delivers primary overcurrent and short-circuit protection for small fractional horsepower motors.
Solenoid & Contactor Circuits: Guards magnetic coils, actuators, and industrial relays from sustained overloads while allowing high peak pulling currents.
HVAC & Industrial Automation Panels: Used in commercial HVAC control boxes, variable frequency drive (VFD) input protection, and PLC power supplies.

Technical Specifications

The primary electrical, physical, and compliance parameters for the FNQ-R-20 TIME DELAY FUSE BUSSMANN are detailed below:

Parameter Specification	Technical Details & Operational Values
Component Classification	Class CC Time-Delay Current-Limiting Fuse
Primary Target Keyword	FNQ-R-20 TIME DELAY FUSE BUSSMANN
Brand / Series	Eaton Bussmann Series / LIMITRON™ FNQ-R
Amperage Rating	$20text{ Amps}$ ( $20text{A}$ )
Voltage Ratings	$600text{ VAC}$ / $300text{ VDC}$
Interrupt Rating (IR)	$200text{ kA}$ at $600text{VAC}$ / $20text{ kA}$ at $300text{VDC}$
Response Characteristic	Time-Delay (Min. $12text{ seconds}$ at $200%$ current)
Fuse Class & Form Factor	UL Class CC Rejection Type ( $13/32'' times 1text{-}1/2''$ / $10.3text{mm} times 38.1text{mm}$ )
Body Material & Terminals	High-Grade Melamine Tube with Nickel-Plated Bronze Ferrules
Agency Certifications	UL Listed (Std 248-4, Guide JDDZ), CSA Certified, CE, RoHS

Operating Guidelines and Usage Tips

SAFETY NOTICE: Always isolate power and de-energize circuits before servicing or replacing power fuses. Use proper lockout/tagout (LOTO) protocols and insulated fuse pullers.

Sizing for Transformers: Size the fuse at approximately $125%$ to $250%$ of the transformer primary full-load current (FLA) according to NEC Article 450 guidelines.

Fuse Block Matching: Pair with UL Class CC modular fuse blocks or DIN-rail holders (such as the Bussmann CHCC series) to utilize the physical rejection feature properly.

To review official Class CC time-delay fuse specifications and electrical installation codes, consult the National Electrical Manufacturers Association (NEMA) Directory.

To check regional warehouse inventory availability or request commercial quotes for volume electrical fuses, visit the Control Qatar Contact Page.

FNQ-R-20 TIME DELAY FUSE BUSSMANN