Littelfuse SPD2-550-M - Surge protection devices (SPDs) provide equipment protection from transient overvoltage events lasting micro-seconds. By limiting the overvoltage to the equipment during these events, costly damage and downtime can be mitigated. The surge protection devices for the 1+0 configuration are available for 60 V to 600 V nominal voltage sub-distribution board applications.
Littelfuse

SPD2-550-M

Alternate Item Number: SPD2-550-M

UPC: 079458253818

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Overview

The Littelfuse SPD2-550-M surge protection device (SPD) is a high-performance solution engineered to shield critical electrical infrastructure from destructive transient overvoltage events. These microsecond-duration spikes, often caused by lightning strikes, switching surges, or utility faults, can inflict irreversible damage on sensitive equipment, leading to costly repairs, unplanned downtime, and compromised operational continuity. Designed for 1+0 configuration applications in sub-distribution boards, the SPD2-550-M operates across a wide nominal voltage range of 60V to 600V, making it an ideal choice for industrial, commercial, and utility environments where voltage stability is paramount. Engineered with Littelfuse’s decades of expertise in surge protection, the SPD2-550-M delivers robust, reliable clamping performance to limit transient overvoltages to safe levels. Its advanced metal oxide varistor (MOV) technology provides fast response times and high energy absorption capacity, ensuring that even the most severe surges are effectively mitigated before they reach downstream equipment. This proactive protection strategy not only preserves the integrity of connected devices—such as PLCs, variable frequency drives (VFDs), motors, and control panels—but also extends the operational lifespan of the entire electrical system. The SPD2-550-M is specifically tailored for sub-distribution board applications, where it serves as a first line of defense against transient events. Its compact and modular design allows for straightforward installation in both new and retrofit projects, with DIN-rail mounting compatibility for seamless integration into existing panel configurations. The device’s 1+0 configuration—featuring a single protective path—simplifies wiring and reduces installation complexity, making it a cost-effective solution for protecting critical circuits without compromising performance. In industrial settings, where equipment reliability is non-negotiable, the SPD2-550-M is trusted to safeguard operations in sectors such as manufacturing, data centers, renewable energy, and healthcare. In data centers, for example, even a brief power surge can disrupt servers, leading to data loss or hardware failure—risks that the SPD2-550-M mitigates by ensuring stable power delivery. Similarly, in renewable energy systems like solar or wind farms, where inverters and controllers are exposed to harsh environmental conditions, this SPD provides essential protection against transient events induced by grid fluctuations or atmospheric discharges. Littelfuse, a global leader in circuit protection solutions, has built a reputation for innovation and reliability in the surge protection industry. With a portfolio that spans low-voltage to high-voltage applications, Littelfuse’s SPDs are trusted by engineers and facility managers worldwide to deliver consistent, long-term performance. The SPD2-550-M exemplifies this commitment, offering a combination of durability, precision, and ease of use that aligns with the demands of modern electrical systems. By integrating this device into your sub-distribution infrastructure, you gain not only immediate protection against transient threats but also long-term peace of mind, knowing that your equipment is shielded by a solution backed by industry-leading expertise and support.
  • Designed for 60V to 600V sub-distribution board applications (1+0 configuration)
  • Mitigates transient overvoltage events lasting microseconds to prevent equipment damage
  • Fast response time with high energy absorption for severe surge protection
  • Compact, DIN-rail mountable design for easy installation in new or retrofit projects
  • Trusted by industrial, commercial, and utility sectors for reliable surge suppression

Specifications

Application
Equipment protection from transient overvoltages
Brand Name
Littelfuse
Mounting Type
DIN-Rail
Series
SPD2
Special Features
DIN Rail Mount
Standard
UL Listed
Sub Brand
SPD2 Series
Type
Type 2 Surge Protection Devices
Voltage Rating
60-600 V
Voltage Rating
60–600 V
Ethernet SHDSL Extender

DDW-120

Ethernet SHDSL Extender
Fiber cable ODC to SC duplex - 670mm

Fiber cable ODC SC Duplex 670mm

Fiber cable ODC to SC duplex - 670mm
Power supply for DIN-rail

PS-60

Power supply for DIN-rail
DIN Rail ? DIN 35

ARH 1656

DIN Rail ? DIN 35
Super-Safeway® Multiple Outlet Box, Extended Depth, 2-Sided, F2 (1/2") Cord Grip Body, with Flip Lids for (2) Duplex Not Included

3085

Super-Safeway® Multiple Outlet Box, Extended Depth, 2-Sided, F2 (1/2") Cord Grip Body, with Flip Lids for (2) Duplex Not Included
18U 24W 36D NWC WINDOW FILTERS

NWC18U2436WFBK

18U 24W 36D NWC WINDOW FILTERS
Cable Manager, fits 19-inch open rack, Black, Steel

ECK19H

Cable Manager, fits 19-inch open rack, Black, Steel
ON OFF SPST Nickel Pull Chain with Cord

75102CW

ON OFF SPST Nickel Pull Chain with Cord
6U PERF PANEL

PPFS19010BK

6U PERF PANEL
This TX6A 10Gig Cat 6A STP Patch Cord is a 12-Meter, Int'l Grey cord constructed of 26 AWG, shielded, twisted pair, stranded, CM/LSZH cable and with high-performance modular plugs. Its tangle-free latch prevents snags and ensures a fast release, streamlining moves, adds, and changes. The slender strain relief boot provides easy access in high-density applications. Enabled with RapidID, the product has pre-installed barcodes for simple port mapping using RapidID software.

STP6X12MIG

This TX6A 10Gig Cat 6A STP Patch Cord is a 12-Meter, Int'l Grey cord constructed of 26 AWG, shielded, twisted pair, stranded, CM/LSZH cable and with high-performance modular plugs. Its tangle-free latch prevents snags and ensures a fast release, streamlining moves, adds, and changes. The slender strain relief boot provides easy access in high-density applications. Enabled with RapidID, the product has pre-installed barcodes for simple port mapping using RapidID software.
OM1 2 fiber, 16mm jacket, patchcord, Riser (OFNR) rated, LC duplex to SC duplex, Std IL

F62ERLNSNSNM002

OM1 2 fiber, 16mm jacket, patchcord, Riser (OFNR) rated, LC duplex to SC duplex, Std IL
Membrane plate cable entry system offers a good strain relief while maintaining IP/NEMA ingress sealing rating. The CESUM3-C15 is a Rectangular Un-Terminated Cable Entry System, 4.1" (103 mm) Long, with 8 Openings 0.12" (3.0 mm) to 0.31" (8 mm), 3 Openings 0.20" (5.1 mm) to 0.35" (9.0 mm), 4 Openings 0.3" (7.5 mm) to 0.47" (12.0 mm). Color is Black. Standard Package Quantity is 1 PC.

CESUM3-C15

Membrane plate cable entry system offers a good strain relief while maintaining IP/NEMA ingress sealing rating. The CESUM3-C15 is a Rectangular Un-Terminated Cable Entry System, 4.1" (103 mm) Long, with 8 Openings 0.12" (3.0 mm) to 0.31" (8 mm), 3 Openings 0.20" (5.1 mm) to 0.35" (9.0 mm), 4 Openings 0.3" (7.5 mm) to 0.47" (12.0 mm). Color is Black. Standard Package Quantity is 1 PC.

Frequently Asked Questions about Littelfuse

What certifications and standards do Littelfuse products comply with?

Littelfuse products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Customers can verify specific product certifications by consulting individual product datasheets on Littelfuse.com, which provide comprehensive details about standards compliance for each component.

What industries and applications are Littelfuse products used for?

Littelfuse products are critical for electrical protection and safety across multiple industrial sectors, including manufacturing, automation, power distribution, and electrical control systems. Their comprehensive product portfolio serves industries that require robust electrical protection, including motor and pump applications, solar installations, programmable logic controllers (PLCs), electrical switch panels, and critical infrastructure environments. Key product lines protect against overcurrent, voltage transients, ground faults, and temperature-related electrical risks, ensuring equipment safety and operational reliability.

What technical support does Littelfuse offer?

Littelfuse offers comprehensive technical support through multiple channels. Their Technical Hotline (800-TEC-FUSE) provides direct access to engineers who can help identify issues and recommend solutions. Additionally, Littelfuse offers extensive online Technical Resources at Littelfuse.com, including datasheets, product manuals, whitepapers, application guides, and online design tools. Their experienced product and application engineers also provide step-by-step support from design to installation.

What are the main product lines offered by Littelfuse?

Littelfuse offers comprehensive industrial protection and control product lines, including fuses, fuse holders, protection relays, temperature sensors, and electrical safety components. Their key product categories span surge protective devices, custom OEM products, electrical switch panels, medium voltage fuses, ground-fault protection relays, motor and pump protection devices, and temperature sensors. These products are designed to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard personnel from electrical faults.

What are the key features of Littelfuse products?

Littelfuse products feature exceptional circuit protection technologies with key characteristics including UL/IEC safety standard compliance, low internal resistance, and advanced protective capabilities across multiple product lines. Their components provide critical protection for industrial systems, offering features like overcurrent protection, voltage transient suppression, and resettable protection devices with ultra-low resistance and compact designs. Key product lines include fuses, metal oxide varistors (MOVs), TVS diodes, PolySwitch devices, and specialized electronic protection components that enhance system reliability and safety.

What environmental ratings do Littelfuse products have?

Littelfuse products feature comprehensive environmental ratings, including NEMA Type 1, 2, 3, 3R, 4/4X, 12, and 13 certifications, as well as IP65 protection. These ratings ensure superior protection in diverse industrial environments, with an operating temperature range of -40°F to +131°F (-40°C to +55°C). Many products also include UV-stabilized materials and neoprene gaskets for enhanced durability in outdoor and challenging conditions.

What accessories are available for Littelfuse products?

Littelfuse offers several key accessories across their product lines, including fuse holders, voltage monitoring modules, and terminal connectors. Specific accessories include the LPSM003ZXID (indicating) and LPSM003Z (non-indicating) POWR-SAFE Dead Front fuse holders for Class CC and Midget-Style fuses, the VRM6048 voltage monitor accessory module, and female quick connect terminals (P1015 series) in various wire gauge sizes. These accessories are designed to enhance protection, monitoring, and connectivity for Littelfuse electrical components.

What is Littelfuse's warranty policy?

Littelfuse provides comprehensive warranty details on their official website at www.littelfuse.com/warranty. Customers should visit this page to review the specific warranty terms and conditions for their specific product lines. For direct warranty support or questions, customers can contact Littelfuse Technical Support at 1-800-TEC-FUSE or email [email protected].

What communication protocols do Littelfuse products support?

Littelfuse supports a comprehensive range of industrial communication protocols, including PROFIBUS, PROFINET, EtherNet/IP, DeviceNet, Modbus RTU, and CANopen. Our products provide flexible connectivity solutions across multiple industrial automation platforms, enabling seamless integration with various control systems and network architectures.

How are Littelfuse products typically installed?

Littelfuse products are typically installed using specialized mounting hardware like fuse holders, blocks, and panels designed for specific industrial applications. The POWR-SAFE Dead Front holders, for example, provide optimum protection for Class CC and Midget-Style fuses, supporting installations up to 600 VAC/DC. Installation often involves using precision terminals with strain relief, such as 0.25 in. female quick connect terminals, to ensure secure and safe electrical connections in industrial control systems.