Mersen A4BY1800 - Fuse A4BY - Class L - Time-Delay 600VAC 300VDC 1800A Blade Amp-Trap®
Mersen

A4BY1800

Alternate Item Number: A4BY1800

UPC: 782001939229


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Overview

The Mersen A4BY1800 is a Class L, time-delay fuse designed for robust protection of critical electrical systems. With a 1800A rating, 600VAC and 300VDC voltage capabilities, and a 200kA interrupting rating (AC) / 100kA (DC), this fuse is engineered for demanding applications. The A4BY series is the industry's preferred choice for safeguarding service entrance equipment, feeder circuits, and circuit breakers. Its 100% rated design allows for continuous current application up to its ampere rating, ensuring full equipment utilization. A key feature is the 4-second minimum time-delay at 500% of its rating, which effectively permits normal current surges to pass while providing crucial coordination with ground fault relays. Constructed with a glass melamine body and plated terminals, the A4BY offers superior reliability even in harsh industrial environments. Blade-stamped catalog numbers ensure permanent identification, and unique dimensions prevent incorrect substitutions by other fuse classes. Applications include mains, feeders, circuit breakers, load centers, panelboards, switchboards, and metering centers. This fuse is UL Listed to standard 248-10 (File E2137) and CSA Certified to standard C22.2 No. 248.10, with self-certification for DC applications per UL248. SKU: A4BY1800. Proudly manufactured in the US.
  • 1800A, 600VAC/300VDC, Class L Time-Delay Fuse
  • 200kA IR (AC) / 100kA IR (DC) interrupting rating
  • 100% rated device for continuous current up to ampere rating
  • 4-second minimum time-delay at 500% rating for surge handling
  • Glass melamine body and plated terminals for harsh environments

Specifications

AC Voltage Rating
600 V
Amperage Rating
1800 A
Application
Mains Feeders Circuit Breakers Load centers Panelboards Switchboards Metering Centers
Body Material
GMG
Brand Name
Mersen
Class
Class L
Connection
Blade
Connection Material
Silver-Plated Copper
Connection Type
Blade
Current Rating
1800A
DC Voltage Rating
300 V
Fuse Class
L
Interrupt Rating
200 kA
Mounting
Bolted
Series
Amp-Trap A4BY
Size
10.75 x 3.5 in
Size
273.05 x 88.9 mm
Special Features
Unique dimensions prevent replacement by other fuse classes Blade-stamped catalog numbers for permanent identification Glass melamine body and plated terminals provide superior reliability in harsh environments
Standard
Mersen Self-Certification, UL Listed to Standard 248-10, File E2137 CSA Certified to Standard C22.2, No. 248.10 IEC 269-2-1 DC Tested to UL 248 limits (Mersen Self-Certified)
Sub Brand
Amp-Trap®
Type
Class L
Voltage Rating
600 VAC
Package Dimensions (L x W x H)
10.75 in x 3.5 in x 3.5 in
Package Dimensions (L x W x H)
273.05 mm x 88.9 mm x 88.9 mm
Package Weight (Imperial)
8.460 lb
Package Weight (Metric)
3.837 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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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.