Technical Specifications

Key Features

Applications

• Motor control transformer supplemental protection
• Compatible 480 VAC control transformer primary circuits
• Industrial AC control circuits with temporary inrush currents
• Industrial electrical control panels and machinery
• Electrical equipment requiring a 25 A time-delay fuse
• Compatible lighting circuit supplemental protection
• Compatible metering and instrumentation circuits
• Industrial equipment maintenance and specified fuse replacement

Purchase Information

We support online purchase of the Bussmann FNQ-25 Time-Delay Midget Fuse. If you need to make bulk purchases and inquire about other products, please contact our team to inform us of your purchase requirements. We will provide you with information such as quantity quotations, delivery dates, and transportation methods.

Frequently Asked Questions

What is the Bussmann FNQ-25?
It is a 25 A, 500 VAC time-delay midget cartridge fuse from the Eaton Bussmann FNQ series, intended for supplemental overcurrent protection in compatible industrial electrical circuits.

Who manufactures FNQ-25?
FNQ-25 belongs to the Eaton Bussmann fuse range. Its manufacturer catalog number is FNQ-25.

What is the rated current?
The rated current is 25 amperes, equivalent to 25,000 milliamperes.

What is the AC voltage rating?
The published maximum AC voltage rating is 500 VAC. The application circuit must remain within the fuse's applicable voltage rating.

Is FNQ-25 a fast-acting fuse?
No. FNQ-25 is a time-delay fuse designed for compatible circuits with temporary inrush currents, including motor control transformer applications. Its suitability should be evaluated using Eaton's published time-current curves.

What is the interrupting rating at 500 VAC?
Eaton specifies an interrupting rating of 10 kA at 500 VAC for FNQ-25, equivalent to 10,000 amperes.

What are the dimensions of FNQ-25?
The nominal dimensions are 10.3 mm in diameter and 38.1 mm in length, approximately 13/32 inch by 1-1/2 inches.

Does FNQ-25 include a blown-fuse indicator?
No. FNQ-25 is a non-indicating cartridge fuse without a built-in visual blown-fuse indicator.

What materials and terminals does FNQ-25 use?
FNQ-25 uses ferrule-to-ferrule connections. Eaton's individual product specification identifies nickel-plated bronze end caps, while FNQ series technical literature describes fiber tube construction and nickel-plated brass end caps. Confirm the precise end-cap alloy with Eaton if material composition is critical.

Can FNQ-25 replace an FNQ-R-25 fuse?
Do not assume these models are interchangeable. FNQ-25 is a 500 VAC supplemental fuse with a 10 kA interrupting rating, whereas FNQ-R-25 belongs to the 600 VAC Class CC fuse series with different protection classifications, interrupting ratings and installation requirements.

Can FNQ-25 be used for branch-circuit protection?
FNQ-25 is intended for supplemental overcurrent protection. Applications requiring branch-circuit protection must use an appropriately classified and rated protective device.

What should be verified before ordering?
Confirm the exact FNQ-25 model number, 25 A current rating, 500 VAC voltage rating, 10 kA interrupting rating, time-delay characteristics, cartridge dimensions and compatibility with the intended fuse holder. Consult Eaton Bussmann FNQ Technical Data 1012 for application specifications.