Mersen A2K90R RK1 Time-delay Fuse 90A 250V

Product Description

The MERSEN A2K90R is a Class RK1 time-delay fuse rated at 90 amps and 250 volts. Class RK1 fuses provide superior current-limiting protection compared to standard Class K fuses, making them a preferred choice for motor branch circuits, HVAC equipment, and industrial load centers that require both overload and short-circuit protection. The time-delay characteristic allows the fuse to ride through harmless inrush currents while still opening quickly on damaging fault conditions. Licensed electricians and HVAC technicians install this fuse type as a code-compliant, high-performance protective device in commercial and residential electrical panels.

The A2K90R is suited for use in motor circuits, compressor circuits, and other inductive loads where nuisance tripping must be minimized without sacrificing fault protection. Its Class RK1 rejection feature prevents the installation of lower-rated fuse classes in the same fuseholder, enforcing the intended protection level at the panelboard. Typical applications include rooftop HVAC units, air compressors, pumps, and other motor-driven equipment operating on 250-volt single-phase or three-phase systems.

Key Features

• Class RK1 current-limiting design provides superior short-circuit protection over standard Class K fuses
• Time-delay action accommodates motor and compressor inrush currents without nuisance opening
• Rejection feature prevents substitution of lower-performance fuse classes in the same holder
• Rated 90 amps at 250 volts for branch-circuit motor and HVAC applications
• Suitable for both single-phase and three-phase 250-volt circuits

Compatibility

Designed as an OEM-style replacement or upgrade for Class RK1 fusible disconnect and panelboard applications rated at 250 volts and 90 amps.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the National Electrical Code (NEC). Always de-energize and lock out the circuit before removing or installing fuses. Use properly rated fuseholders that accept Class RK1 rejection fuses. Do not substitute a lower-rated fuse class or a higher ampere rating for this device.

Technical Specifications

• Ampere Rating: 90 amps
• Voltage Rating: 250 volts
• Fuse Class: RK1
• UPC: 78200191521

Standard Information

• Brand: MERSEN
• Manufacturer Part Number: A2K90R