Mersen 30782001749072 Class RK5 Time-delay Fuse 70A 600V

Product Description

The MERSEN 30782001749072 is a dual-element, time-delay, current-limiting fuse rated at 70 amps and 600 volts, classified as Class RK5 with a built-in rejection feature. Known in the trade as the Tri-Onic series, this fuse is engineered for branch-circuit and motor-circuit overcurrent protection in industrial electrical systems. The dual-element design separates the overload-sensing function from the short-circuit-sensing function, allowing the fuse to ride through normal motor startup inrush currents without nuisance opening while still providing fast response to genuine fault conditions. Licensed electricians and industrial maintenance technicians are the primary installers of this device.

This fuse is suited for industrial applications where reliable overcurrent protection is required on branch circuits and motor circuits. The Class RK5 rating with rejection feature prevents substitution of lower-performing fuse classes into the same fuseholder, maintaining the integrity of the overcurrent protection scheme. Typical installations include motor control centers, panelboards, disconnect switches, and combination motor starters in commercial and industrial facilities.

Key Features

• Dual-element construction tolerates motor inrush current while responding to sustained overloads and short circuits
• Time-delay characteristic reduces nuisance tripping on motor startup loads
• Current-limiting design reduces available fault energy at the protected circuit
• Class RK5 rejection feature prevents installation of non-rejection fuses in RK5 fuseholders
• 70-amp rating suitable for motor branch circuits and general-purpose branch circuits up to 600 volts

Compatibility

Designed as an OEM-style replacement for Class RK5 time-delay fuses used in industrial branch-circuit and motor-circuit protection applications rated up to 600 volts.

Installation Notes

Installation must be performed by a qualified, licensed electrician in accordance with the National Electrical Code (NEC) and applicable local codes. De-energize and lock out the circuit using proper lockout/tagout (LOTO) procedures before removing or installing any fuse. Verify the fuseholder is rated for Class RK5 rejection-style fuses and confirm the circuit voltage and amperage do not exceed the fuse rating. Never replace a blown fuse without first identifying and correcting the root cause of the overcurrent condition.

Technical Specifications

• Amperage Rating: 70 amps
• Voltage Rating: 600 volts
• Fuse Class: RK5
• Fuse Type: Dual-element time-delay current-limiting
• Rejection Feature: Yes

Standard Information

• Brand: MERSEN
• Manufacturer Part Number: 30782001749072