Overview
The Littelfuse KLDR 3 is a Class CC time delay cartridge fuse designed to protect control transformers, solenoids, and similar inductive components with high magnetizing currents during the first half-cycle. With a 3A ampere rating and 600V AC/300V DC voltage rating, these fuses provide reliable overcurrent protection while minimizing nuisance trips from normal inrush currents. The compact 10 x 38mm cartridge design saves approximately 70% of panel space compared to larger fuse classes like Class R.
Key Features
- Time Delay (Slow-Blow): Designed to tolerate inductive inrush currents without nuisance operation
- Class CC Cartridge: Smallest UL-listed fuse class, ideal for space-constrained control circuits
- High Interrupt Rating: 200 kA at 600 VAC and 20 kA at 300 VDC
- Dual Voltage Rating: Rated for both AC (600V) and DC (300V) applications
- UL/CSA Certified: Meets UL JDDZ E81895 and CSA 1422-02 standards
- Current Limiting: Provides superior overcurrent limiting compared to other fuse classes
Technical Specifications
Electrical:
- Ampere Rating: 3A
- Voltage (AC): 600V
- Voltage (DC): 300V
- Interrupt Rating: 200 kA @ 600 VAC; 20 kA @ 300 VDC
- Speed: Time Delay (Slo-Blo)
- Class: UL Class CC
Physical:
- Cartridge Diameter: 0.406 inches (10.31 mm)
- Cartridge Length: 1.5 inches (38.1 mm)
- Weight (per unit): 0.32 oz
- Packaging: Pack of 12 sealed fuses
Typical Applications
- Control transformer protection in motor control centers
- Solenoid and relay circuit protection
- Inductive load circuits subject to high inrush currents
- Motor branch circuits with NEMA/IEC motor controllers
- Industrial control panels and lighting circuits
- Machine tool automation and PLC systems
Compatibility & Replacements
Compatible With
- Standard Class CC fuse holders and blocks
- Industrial control panels using cartridge fuse receptacles
- Motor control centers and distribution boards
- Transformer primary protection circuits
- Any circuit designed for Class CC fuse protection
Replaces / Drop-In Replacement For
- KLDR003 (alternative part number designation)
- KLDR-003
- Other Class CC 3A time delay fuses in 10x38mm cartridge format
Works With
- Class CC fuse blocks and holders
- Standard UL Class CC cartridge receptacles (10x38mm)
- Motor branch circuits and control transformer circuits
- Systems requiring 600VAC/300VDC rated protection devices










