Overview
The Cefco CRS-R70 Class RK-5 dual element time delay fuse delivers reliable overcurrent protection for industrial circuits operating at 600VAC and 70A. Unlike fast-acting fuses, the CRS-R70’s dual-element construction tolerates harmless inrush currents from motors and transformers while maintaining fast response to dangerous short circuits. This makes it ideal for applications where nuisance trips must be minimized without sacrificing safety.
Key Features
- Dual-element time-delay construction: Handles motor startup inrush without false trips; responds rapidly to sustained overloads and shorts
- 600VAC rated voltage: Suitable for single- and three-phase industrial power distribution circuits
- 70A current rating: Protects circuits drawing up to 70 amps continuous
- Class RK-5 UL listed: Meets UL and CSA standards for current-limiting, time-delay protection
- Bolt-mount terminal: Secures directly to fuse blocks and disconnect switches
- Low cost of operation: Time-delay design allows use of smaller amp ratings than fast-acting fuses, reducing panel and switch sizing costs
Technical Specifications
Electrical:
Rated Voltage (AC): 600V
Current Rating: 70A
Fuse Class: Class RK-5
Fuse Type: Dual Element Time Delay
Short-Circuit Breaking Capacity: 200 kA (RMS symmetrical)
Physical:
Mounting Style: Bolted blade terminal
Diameter: 1.1 in. (28.2 mm)
Length: 8 in. (200.2 mm)
Approvals:
UL Listed – Standard 248-12
CSA Certified – C22.2 No. 248.12 Class RK5
Typical Applications
- Motor branch circuits: Protects motors from overload and short-circuit faults while tolerating starting surge currents
- Transformer feeds: Guards transformer primary circuits against inrush magnetizing currents
- Industrial machinery: Applied in variable-frequency drives, industrial control panels, and production equipment
- HVAC systems: Provides main disconnect protection for commercial and industrial heating/cooling units
- Power distribution: Used in distribution panels and subpanels where time-delay protection is required
Compatibility & Replacements
Compatible With
- Standard bolt-mount fuse blocks rated 600VAC
- Disconnect switches and safety switches with cartridge fuse holders
- Industrial control panels and power distribution cabinets
- Systems requiring Class RK-5 UL-listed fuses
- Three-phase and single-phase power circuits up to 600VAC
Replaces / Drop-In Replacement For
- Bussmann Fusetron FRS-R-70 (Class RK-5, 600VAC, 70A)
- Cooper Bussmann FRS-R-70
- Other equivalent Class RK-5 70A dual-element time-delay fuses
Works With
- UL Class RK-5 fuse holders and blocks
- Industrial fuse pullouts and clips rated for 600VAC
- Motor control centers and disconnect switches
- Any system utilizing standard 600VAC bolt-mount cartridge fuses
