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Mersen OT1 - One-Time OT and OTN general purpose fuses provide low cost protection for feeder and branch-circuits serving lighting, heating, and other non-motor loads. OT and OTN fuses will safely interrupt available short-circuit currents up to 50,000 amperes in all ratings. OT and OTN fuses are not rejection fuses and care should be taken to ensure that replacement fuses do not have lower interrupting ratings than original fuses. OTN(15-60) satisfy the Canadian electrical code requirement for Type P low melting-point, non-time-delay fuses. 250 Volts 1 amps OT series.

Mersen OT1 One-Time OT and OTN general purpose fuses provide low cost protection for feeder and…

Alternate Item Number: 782001700003

UPC: 782001700003


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Specification Sheet

Contact for Pricing

Call +1 (262) 252-1600 (toll-free 877-268-3700) or email [email protected] for pricing and availability.

Overview

The Mersen OT1 (SKU: OT1) is a Class K-5 general purpose fuse designed for cost-effective overcurrent protection in feeder and branch circuits serving non-motor loads such as lighting, heating, and resistive applications. Rated at 1 Ampere and 250 Volts AC/DC, this fuse provides reliable safeguarding with an interrupting rating of 50,000 amperes (50kA I.R. AC) and 20,000 amperes (20kA I.R. DC). Engineered for versatility, the OT1 fuse is ideal for residential and small commercial installations where dependable protection is required without excessive cost. Its non-rejection design ensures compatibility with existing systems, but users must verify that replacement fuses meet or exceed the original interrupting rating to maintain safety. The OT1 fuse features an easy-to-read imprint label for quick identification and replacement, streamlining maintenance workflows. For Canadian installations adhering to the Canadian Electrical Code, OTN variants (15-60A) are required for Type 'P' low melting-point, non-time-delay applications. Applications include feeders, branch circuits, and resistive heating systems where non-inductive loads dominate. Mersen’s OT series fuses are trusted for their balance of performance and economy, offering a practical solution for circuits demanding dependable protection without compromising safety or performance.
  • Class K-5 general purpose fuse for non-motor loads (lighting, heating, resistive applications)
  • Rated 1A at 250V AC/DC with 50kA interrupting rating (AC) and 20kA (DC)
  • Non-rejection design; ensure replacement fuses meet or exceed original interrupting rating
  • Easy-to-read imprint label for quick identification and replacement
  • Suitable for feeders, branch circuits, and residential/small commercial installations

Specifications

Amperage Rating
1 A
Application
Feeders Resistive Heating Residential and Small Commercial Installations
Brand Name
Ferraz Shawmut
Class
Class K5
Connection
Ferrule
Interrupt Rating
50 kA
Mounting
Clip
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 DC Tested to UL Standard 248 (Mersen Self-Certified)
Type
North American Power Fuses
Voltage Rating
250 VAC
Package Dimensions (L x W x H)
2 IN x 0.562 IN x 0.562 IN
Package Dimensions (L x W x H)
5.08 cm x 14.2748 mm x 14.2748 mm
Package Weight (Imperial)
0.040 L
Package Weight (Metric)
0.018 kg
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POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

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POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

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.