Overview
The Reliance ECSR-3-1/2 is a dual-element, time-delay Class RK5 fuse offering dependable overcurrent protection for industrial and commercial electrical systems. Rated at 3.5A and 600Vac, this cartridge-style fuse incorporates current-limiting technology to minimize damage from short circuits and transient surges. The package contains four fuses, providing ready backup stock for maintenance techs and system integrators.
Key Features
- Dual-Element Design — Provides selective clearing without nuisance trips, preventing unnecessary circuit interruptions.
- Time-Delay (Melting Alloy) — Withstands brief inrush currents while responding reliably to sustained overloads.
- Class RK5 Current-Limiting — Restricts peak let-through current to protect downstream components and reduce system stress.
- 600V Rating — Rated for AC systems up to 600 volts, standard in North American industrial control circuits.
- UL and CSA Certified — Meets UL (Guide JDDZ) and CSA safety standards for code-compliant installations.
- 4-Pack Convenience — Bulk quantity reduces downtime by maintaining spare inventory on-site.
Technical Specifications
| Label | Value |
| Part Number | ECSR-3-1/2 |
| Manufacturer | Reliance Electric |
| Current Rating | 3.5 Amperes (AC) |
| Voltage Rating | 600 Volts AC |
| Fuse Type | Dual-Element Time-Delay |
| Class | RK5 |
| Agency Listings | UL Listed (File E162363), CSA Certified |
| Quantity Per Package | 4 units |
| Series | ECSR (600V Time-Delay) |
| DC Interrupting Rating | 20,000 Amperes |
Typical Applications
- Machine tool motor circuits and spindle drives
- HVAC transformer protection and heating element circuits
- Industrial control panel and PLC system power feeds
- Conveyor and automation equipment branch circuits
- General-purpose industrial distribution and load centers
- Replacement stock for existing RK5-compatible installations
Compatibility & Replacements
Compatible With
- Class RK5 fuse clips and cartridge holders (NEMA standard)
- Industrial control panels rated 600V and below
- Motor starter circuits with time-delay protection requirements
- Three-phase and single-phase distribution systems
- Machine tool control circuits
- Disconnect switches and fusible equipment
Replaces / Drop-In Replacement For
- Older Reliance ECSR-3-1/2 cartridge fuses (direct equivalent)
- Generic Class RK5 3.5A 600V time-delay cartridges of equivalent physical dimensions
- Similar dual-element fuses in existing installations with matching footprint and ratings
Works With
- Class RK5 fusible equipment and panelboards
- Industrial automation and motor control systems
- Electrical distribution systems requiring current-limiting protection
- Standard cartridge fuse holders with RK5 Class R compatibility
- Overcurrent protective device coordination in industrial circuits
