Littelfuse SOO.500 Time Delay Fuse 0.5A 125V S Base

Product Description

The LITTELFUSE SOO.500 is a time delay fuse rated at 0.5 amps and 125 volts, designed for S base (Edison-style rejection base) fuse holders. Time delay fuses are engineered to tolerate brief inrush currents — such as motor start surges — without nuisance tripping, while still providing reliable overcurrent protection under sustained fault conditions. This fuse type is commonly used in residential and light commercial electrical panels, appliance branch circuits, and HVAC control circuits where momentary load spikes are expected. Installation requires a qualified electrician or HVAC technician familiar with applicable NEC guidelines.

The SOO.500 fits S base fuse holders, which feature a rejection design that prevents substitution with a higher-rated fuse. This makes it well suited for circuits requiring tamper-resistant overcurrent protection. Typical applications include low-amperage branch circuits in residential panels, appliance control wiring, and supplemental protection in HVAC equipment control panels. The 0.5-amp rating targets very low-load circuits where precise overcurrent protection is critical.

Key Features

• Time delay design tolerates motor inrush and transient surges without nuisance tripping
• S base (rejection base) construction prevents installation of higher-rated fuses
• 0.5 amp rating provides precise protection for low-load circuits
• 125 volt rating suitable for standard residential branch circuit applications

Compatibility

Designed as an OEM-style replacement for S base time delay fuses in residential and light commercial electrical panels and HVAC control circuits rated at 125 volts or less.

Installation Notes

Always de-energize and lock out the circuit before replacing a fuse. S base fuse holders have a built-in rejection feature — use only the correct amperage rating for the circuit as required by NEC Article 240. A licensed electrician should verify the circuit's overcurrent protection requirements before installing a replacement fuse. Never bypass or substitute a fuse with a higher-rated device.

Technical Specifications

• Amperage Rating: 0.5 amps
• Voltage Rating: 125 volts
• Fuse Type: Time Delay
• Base Type: S Base
• UPC: 07945841024

Standard Information

• Brand: LITTELFUSE
• Manufacturer Part Number: SOO.500