Mersen AOS-S - Add-On-Switches contain one single-pole doublethrow contact rated 4 amperes resistive and 1 ampere inductive at 250V AC maximum. Two versions of the Add-On-Switch are available. Catalog number -S has screw terminals
Mersen

AOS-S

Alternate Item Number: 782001942359

UPC: 782001942359

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Minimum Qty: 10

Multiplier: 10

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Overview

The Mersen AOS-S Add-On Switch (SKU: AOS-S) is a single-pole double-throw (SPDT) auxiliary switch designed for industrial control and automation systems. Rated at 4 amperes for resistive loads and 1 ampere for inductive loads at 250V AC maximum, this compact switch provides reliable switching for auxiliary control circuits, remote signaling, or circuit breaker interlocks. The AOS-S features secure screw terminals for stable wiring connections, making it ideal for environments with vibration or frequent maintenance. Unlike push-on connector versions (AOS-Q), the AOS-S ensures a mechanically robust termination suitable for high-reliability applications. With a single-pole configuration, it enables control of two separate circuits or switching between two states within a single circuit, enhancing system flexibility. Commonly deployed in manufacturing, material handling, HVAC, and building automation, the AOS-S integrates seamlessly into crowded electrical enclosures due to its compact form factor. Its SPDT contact design allows for auxiliary functions such as status indication, interlocking, or custom logic sequencing in automation panels. The switch’s 250V AC rating aligns with standard industrial power supplies, while its 4A resistive/1A inductive current handling covers typical control signal and low-power load requirements. Mersen’s engineering ensures long-term operational integrity, with durable construction suited for challenging industrial conditions. Professionals in electrical engineering, panel building, and system integration rely on the AOS-S for cost-effective, dependable switching solutions that meet UL/cULus standards.
  • Single-pole double-throw (SPDT) contact configuration for versatile switching
  • Rated 4A resistive / 1A inductive at 250V AC maximum
  • Secure screw terminals for stable wiring in high-vibration environments
  • Compact design for easy integration into crowded control panels
  • Compatible with standard industrial power supplies and automation systems

Specifications

Amperage Rating
4 A
Brand Name
Ferraz Shawmut
Connection
Screw
Mounting
Snap On
Special Features
Add-On-Switches contain one single-pole doublethrow contact rated 4 amperes resistive and 1 ampere inductive at 250V AC maximum. Two versions of the Add-On-Switch are available
Type
Blown Fuse Indicators
Voltage Rating
250 VAC
Package Dimensions (L x W x H)
1.27 IN x 0.64 IN x 0.64 IN
Package Dimensions (L x W x H)
3.2258 cm x 16.256 mm x 16.256 mm
Package Weight (Imperial)
0.060 L
Package Weight (Metric)
0.027 kg
Add-On-Switches contain one single-pole doublethrow contact rated 4 amperes resistive and 1 ampere inductive at 250V AC maximum. Two versions of the Add-On-Switch are available. Catalog number -Q accommodates quick connects

AOS-Q

Add-On-Switches contain one single-pole doublethrow contact rated 4 amperes resistive and 1 ampere inductive at 250V AC maximum. Two versions of the Add-On-Switch are available. Catalog number -Q accommodates quick connects
For use with Littelfuse FLNR_ID/FLSR_ID, IDSR, LLNRK/LLSRK and KLNR/KLSR series fuses.

LRU-616R

For use with Littelfuse FLNR_ID/FLSR_ID, IDSR, LLNRK/LLSRK and KLNR/KLSR series fuses.

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.