Mersen AJT500 - Fuse AJT - Class J - Time-delay 600VAC 500VDC 500A Blade SmartSpot® Amp-Trap 2000®
Mersen

AJT500

Alternate Item Number: AJT500

UPC: 782001962173


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Overview

The Mersen AJT500 Class J time-delay fuse delivers superior circuit protection with advanced material technology, offering IEC Type 2 No Damage protection for main, feeder, and branch circuits. Rated for 600VAC or 500VDC, this 500A fuse handles motor and transformer inrush currents with time-delay characteristics while providing exceptional current-limiting performance. Its SmartSpot® visual open fuse indicator (available in 8-600A models) enables quick fault identification, reducing downtime. The AJT500 requires only half the mounting space of 600VAC Class RK fuses, optimizing panel design and cost efficiency. With a 300kA interrupting rating (self-certified, UL witnessed), it meets the most demanding industrial applications. UL/CSA listed to standards 248-8 and C22.2 No. 248.8, this fuse is ideal for motor circuits, transformers, bus ducts, and control panels. The fiberglass body and high-grade silica filler ensure dimensional stability and fast arc quenching in harsh environments. The Amp-Trap 2000® series fuses are designed to provide high performance and reliability.
  • 600VAC/500VDC rated, 500A current capacity
  • SmartSpot® visual open fuse indicator (8-600A models)
  • IEC Type 2 No Damage protection for all load types
  • 300kA interrupting rating (self-certified, UL witnessed)
  • Half the mounting space of Class RK fuses

Specifications

AC Voltage Rating
600 V
Amperage Rating
500 A
Application
Motor circuits Mains Feeders Branch circuits Lighting, heating & general loads Transformers Control panels Circuit breaker back-up Bus duct Load centers
Body Material
GMG
Brand Name
Mersen
Class
Class J
Connection
Blade
Connection Material
Brass
Connection Type
Blade
Current Rating
500A
Interrupt Rating
200 kA
Mounting
Clip or Bolted
Nema Rating
Class J
Series
Amp-Trap 2000®
Size
8 x 2.5;203.2 x 63.5 in;mm
Size
8 x 2.5 in
Size
203.2 x 63.5 mm
Special Features
Non-indicating or solid state SmartSpot visual blown fuse indicator Time-delay for motor starting and transformer inrush 300kA interrupting rating - self-certified, UL witnessed tests Extremely current-limiting for low peak let-thru current Most current-limiting UL class fuse Recommended for Arc Flash energy reduction Small footprint requires less mounting space and allows smaller, more economical fuse blocks Easy 2-to-1 selectivity for prevention of nuisance shutdowns Unique Class J dimensions prevent replacement errors High-visibility orange label gives instant brand recognition Metal-embossed date and catalog number for traceability and lasting identification Fiberglass body provides dimensional stability in harsh industrial settings High-grade silica filler ensures fast arc quenching Optional EI indicator/switch mount for AJT70 to 600 open fuse indication
Special Features
Non-indicating or solid state SmartSpot visual blown fuse indicator Time-delay for motor starting and transformer inrush Self Certified 700VAC, 15-600A range, 100kA IR 300kA interrupting rating - self-certified, UL witnessed tests Extremely current-limiting for low peak let-thru current Most current-limiting UL class fuse Recommended for Arc Flash energy reduction Small footprint requires less mounting space and allows smaller, more economical fuse blocks Easy 2-to-1 selectivity for prevention of nuisance shutdowns Unique Class J dimensions prevent replacement errors High-visibility orange label gives instant brand recognition Metal-embossed date and catalog number for traceability and lasting identification Fiberglass body provides dimensional stability in harsh industrial settings High-grade silica filler ensures fast arc quenching Optional EI indicator/switch mount for AJT70 to 600 open fuse indication
Standard
AJT (1-600): UL listed to standard 248-8 File E2137 DC listed to UL standard 248 CSA certified to standard C22.2 No. 248.8 IEC 60269-2-1 AJT (70-600) EI: UL listed DC tested to UL standard 248
Standard
AJT (1-600): UL listed to standard 248-8 File E2137 DC listed to UL standard 248 CSA certified to standard C22.2 No. 248.8 IEC 60269-2-1 AJT (70-600) EI: UL listed DC tested to UL standard 248 Self Certified 700VAC, 15-600A range
Sub Brand
Amp-Trap 2000®
Type
Class J
Type Of Indicators
SmartSpot®
Voltage Rating
600 VAC
Package Dimensions (L x W x H)
8 in x 2.5 in x 2.5 in
Package Dimensions (L x W x H)
203.2 mm x 63.5 mm x 63.5 mm
Package Weight (Imperial)
3.020 lb
Package Weight (Metric)
1.370 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.
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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.