Littelfuse ELCT5-31 - CT 100:1 WITH FLUX COND 31MM
Littelfuse

ELCT5-31

Alternate Item Number: ELCT5-31

UPC: 079458232660


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Overview

The Littelfuse ELCT5-31 Current Transformer (CT) is a high-precision, sensitive current sensing solution engineered for low-level earth-leakage detection in industrial protection and monitoring systems. Designed as part of the ELCT series with an integrated flux conditioner, this CT is optimized for seamless integration with Littelfuse relays—particularly the SE-701 series—to deliver accurate current measurement even at minimal signal levels. With a 100:1 turns ratio and a 31mm internal diameter window, the ELCT5-31 is ideal for detecting subtle current imbalances in power distribution networks, motor control circuits, and industrial automation systems where early fault detection is critical to preventing equipment damage and downtime. Engineered for reliability in demanding industrial environments, the ELCT5-31 operates across a wide frequency range of 50 to 400 Hz, ensuring compatibility with global power systems and variable-speed drives. Its robust construction supports an insulation level of 600V and withstands extreme operating temperatures from -40°C to 55°C (-40°F to 131°F), making it suitable for harsh and outdoor installations. The unit is certified to UL, cUL, and CE standards, and complies with RoHS, IEC 61869-2, and ANSI/IEEE C57.13, underscoring its adherence to international safety and performance benchmarks. Key performance attributes include a secondary exciting current of 0.1 mA at 0.01 VA for the ELCT5-31, enabling high sensitivity to low-level currents—essential for earth-fault and leakage protection. The integrated flux conditioner enhances signal integrity by minimizing distortion and improving response time, which is vital in applications such as motor protection, generator monitoring, and renewable energy systems. The compact 31mm window accommodates conductor sizes from 0.05 mm² to 3.3 mm² (12–30 AWG), offering installation flexibility without compromising performance. Installation is straightforward, with mounting via M5 or #10 screws and a recommended tightening torque of 0.5 N·m for secure, vibration-resistant attachment. Wiring follows a standard CT configuration, with secondary leads connected to compatible Littelfuse relays such as the SE-330 or SE-704 (for ELCT30 variants), ensuring seamless integration into existing protection schemes. The unit’s lightweight design (127.0 g / 0.28 lbs) and compact footprint facilitate easy retrofitting into control panels and switchgear. Littelfuse, a global leader in circuit protection and sensing technologies, brings decades of expertise to the ELCT series. Known for innovation in current sensing, power distribution, and industrial automation, Littelfuse products are trusted by engineers and technicians worldwide for their accuracy, durability, and compliance with rigorous industry standards. The ELCT5-31 exemplifies this commitment, offering a dependable solution for precise current measurement in mission-critical applications where reliability cannot be compromised. Whether deployed in manufacturing plants, data centers, or renewable energy installations, the ELCT5-31 delivers consistent performance, reduced maintenance costs, and enhanced system safety—making it an essential component in modern industrial protection architectures.
  • 100:1 turns ratio with 31mm window for precise low-level current detection
  • Integrated flux conditioner minimizes signal distortion and enhances response time
  • Operates from 50 to 400 Hz; suitable for global power systems and variable-speed drives
  • Rated for -40°C to 55°C; 600V insulation; UL, cUL, CE certified
  • Lightweight (127g) with M5 mounting; compatible with Littelfuse SE-330 and SE-704 relays

Specifications

Connection Type
Secondary leads (CT configuration)
Frequency
50-400 Hz
Mounting Type
M5 or #10 screws
Series
ELCT
Size
31mm window
Voltage Rating
600 V
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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.