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Mersen OT20 - Fuse OT - Class K5 - Fast-Acting 250VAC 250VDC 20A Ferrule Amp-Trap®
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Mersen OT20 Fuse OT - Class K5 - Fast-Acting 250VAC 250VDC 20A Ferrule Amp-Trap®

Alternate Item Number: OT20

UPC: 782001700126


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Contact for Pricing

Minimum Qty: 10

Multiplier: 10

*Contact for lower quantities*

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

Overview

The Mersen OT20 (SKU: OT20) is a Class K5, fast-acting ferrule fuse designed for reliable protection of feeder and branch circuits in non-motor applications. Rated for 250VAC and 250VDC, this 20A fuse delivers robust short-circuit interruption with an interrupting rating (IR) of 50,000 amperes AC and 20,000 amperes DC. Ideal for lighting, heating, and general-purpose circuits, the OT20 ensures secure connections via its ferrule design in compatible fuse holders. The clear imprint label enables quick identification and replacement. 248.9. Note: OT and OTN fuses are not rejection types;
  • Class K5 fast-acting ferrule fuse for non-motor applications
  • 20A current rating with 250VAC/250VDC voltage rating
  • 50kA AC and 20kA DC interrupting rating for robust short-circuit protection
  • Ferrule design ensures secure connections in compatible fuse holders
  • Clear imprint label for quick identification and replacement

Specifications

AC Voltage Rating
250 V
Amperage Rating
20 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
Connection Type
Ferrule
Current Rating
20A
DC Voltage Rating
250 V
Interrupt Rating
50 kA
Mounting
Clip
Series
Amp-Trap®
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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Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

E1062696

Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20
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.

LCC5

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.
9F61 Size B Clips 1.6in

9F61BWW460

9F61 Size B Clips 1.6in

Frequently Asked Questions

What is the interrupting rating of the OT20 fuse?

The OT20 fuse has an interrupting rating of 50,000 amperes AC and 20,000 amperes DC.

Is the OT20 fuse suitable for motor applications?

No, the OT20 is designed for non-motor applications such as lighting, heating, and general-purpose circuits.

What voltage ratings does the OT20 support?

The OT20 supports 250VAC and 250VDC voltage ratings.

What is the current rating of the OT20 fuse?

The OT20 fuse has a current rating of 20 amperes.

What type of fuse holder is compatible with the OT20?

The OT20 uses a ferrule design for secure connections in compatible fuse holders.

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.