Mersen OT25 - Fuse OT - Class K5 - Fast-Acting 250VAC 250VDC 25A Ferrule Amp-Trap®
Mersen

OT25

Alternate Item Number: OT25

UPC: 782001700133


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Overview

The Mersen OT25 (SKU: OT25) is a fast-acting Amp-Trap® Class K5 fuse engineered for reliable, low-cost protection of feeder and branch circuits. Rated for 25A, this ferrule-type fuse offers a 50kA interrupting rating at 250VAC and 20kA at 250VDC, ensuring safe interruption of short-circuit currents. It is ideal for general-purpose applications including lighting, heating, and other non-motor loads where time-delay is not required. The OT series fuses are not rejection fuses; therefore, it is crucial to ensure replacement fuses have equal or higher interrupting ratings than the original. The Mersen OT25 is UL Listed to Standard 248-9 (File E2137) and CSA Certified to Standard C22.2 No. 248.9. Its easy-to-read imprint label facilitates quick recognition and replacement. This fuse is a versatile and economical choice for residential and small commercial installations, providing essential circuit protection. For optimal performance and safety, always consult the manufacturer's guidelines for fuse selection and replacement.
  • Fast-acting Amp-Trap® Class K5 fuse for reliable circuit protection
  • Rated for 25A, 250VAC, and 250VDC
  • High interrupting rating: 50kA at 250VAC, 20kA at 250VDC
  • Ideal for general-purpose loads like lighting and heating
  • UL Listed to Standard 248-9 and CSA Certified to Standard C22.2 No. 248.9

Specifications

AC Voltage Rating
250 V
Amperage Rating
25 A
Application
Feeders Branch circuits Resistive heating Residential and small commercial installations
Body Material
Paper
Brand Name
Mersen
Class
Class K5
Connection
Ferrule
Connection Material
Copper
DC Voltage Rating
250 V
Interrupt Rating
50 kA
Mounting
Clip
Size
2 x 0.56 in
Size
50.8 x 14.275 mm
Special Features
Easy to read imprint label for quick recognition and replacement Low cost for high protection value
Standard
UL Listed to Standard 248-9 File E2137 CSA Certified to Standard C22.2 No. 248.9 (The Canadian Electrical Code requires these fuses in ratings 15 through 60A to be of the low melting point design use OTN 15-60.) Self-certified for DC per UL248
Sub Brand
Amp-Trap®
Type
Class K5
Voltage Rating
250 VAC
Package Dimensions (L x W x H)
2 in x 0.56 in x 0.56 in
Package Dimensions (L x W x H)
50.8 mm x 14.275 mm x 14.275 mm
Package Weight (Imperial)
0.029 lb
Package Weight (Metric)
0.013 kg
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Frequently Asked Questions about Mersen

What industries and applications are Mersen products used for?

Mersen products are used across diverse industrial sectors including solar power, electric vehicles, buildings/construction, industrial automation, power distribution, HVAC, elevators, telecommunications, and specialty manufacturing. Key application areas include circuit protection, surge protection, battery module protection, electrical safety systems, and power management for residential, commercial, and utility-scale installations.

What are the main product lines offered by Mersen?

Mersen offers five primary electrical power product lines: IEC and UL/CSA Fuses and Fusegear, Surge Protection, Low Voltage Disconnect Switches, Power Distribution Blocks, and Engineered Solutions. Their comprehensive range includes specialized components like high-speed fuses, modular fuse holders, surge arresters, and custom-engineered electrical protection systems for industrial and power management applications.

What are the key features of Mersen products?

Mersen products feature advanced electrical protection and power management solutions with key characteristics including finger-safe design, compact modularity, and high-performance safety features. Their product lines span electrical power components like fuses, surge protection, power distribution blocks, and specialized solutions for industrial, solar, and building applications. Critical features include UL/CSA approvals, high short-circuit current ratings, and innovative technologies like the Fuse Control™ program that minimize electrical risks and optimize system performance.

What environmental ratings do Mersen products have?

Mersen products meet rigorous environmental ratings across multiple standards, including UL 508A Type 1, 2, 3, 4, 4X, 12, and 13, CSA Type 1, 2, 3, 4, 4X, 12, and 13, and NEMA Type 1, 2, 3, 4, 4X, 12, and 13. They feature IEC 60529 IP66 protection, with enhanced UV inhibitors for outdoor weathering and operating temperatures ranging from -40°C to 130°C (-40°F to 266°F). These ratings ensure superior protection in wet, corrosive, and challenging industrial environments.

What accessories are available for Mersen products?

Mersen offers multiple accessories for their fuse blocks and systems, including safety pullers (DFC3M and DFC3LP), DIN-rail adapters (DRM), bus bars, auxiliary contacts, and specialized mounting hardware. Key accessories include the DFC3M safety puller for 1-1/2" x 13/32" midget or Class CC fuses, the DRM adapter for mounting 303 series fuse blocks on DIN-rail, and UltraSafe fuse module accessories like bus bars and auxiliary contacts that enable module interconnection and monitoring.

How are Mersen products typically installed?

Mersen products are typically installed in electrical distribution systems, control panels, and industrial automation environments using multiple mounting options. These include service entrance panel mounting, distribution panel installation, control panel DIN rail mounting, and custom engineered solutions like Fused Coordination Panelboards. Installation depends on the specific product type, such as fuses, surge protective devices, or switches, and is designed to provide electrical protection and circuit safety in various industrial and commercial applications.

What certifications and standards do Mersen products comply with?

Mersen products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Our products meet rigorous safety and performance standards for industrial applications across North America, China, Russia, and other global markets, ensuring compliance and reliability in electrical power and advanced materials solutions.

What technical support does Mersen offer?

Mersen provides comprehensive technical support through multiple channels, including technical experts located in your time zone who can assist with product selection, application guidance, and troubleshooting. Their Fuse Control™ program offers a free Fuse Inventory Audit & Analysis, and customers can access technical resources through their sales representatives and online platform ep.mersen.com.