Littelfuse TOO01.8 - Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse

TOO01.8

Alternate Item Number: 0TOO01.8Z

UPC: 079458430400

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Overview

The **Littelfuse TOO01.8 Plug Fuse (SKU: TOO01.8)** delivers trusted overcurrent protection for general-purpose circuits and small motor loads, adhering to the highest safety and compliance standards. Designed with an **Edison-base configuration featuring durable metal threads**, this fuse is engineered for seamless integration with standard incandescent lamp bases, making it the ideal replacement solution for existing installations. Unlike Type S fuses, the TOO series is permitted by the **National Electrical Code (NEC)** for replacement purposes only, ensuring compatibility with legacy systems while mitigating risks associated with improper fuse selection. Plug fuses like the TOO01.8 are critical components in **low-voltage distribution systems**, providing fast-acting protection against overcurrent events that could damage wiring, equipment, or create fire hazards. The Edison-base design simplifies installation—simply screw the fuse into a compatible socket without additional adapters—while its **metal-threaded construction** ensures reliable electrical contact and mechanical stability. This design is particularly valuable in **commercial buildings, industrial facilities, and residential applications** where retrofitting or maintaining older electrical systems is common. **Key Features and Benefits:** - **NEC-Compliant Design:** The TOO01.8 complies with **NEC Article 240.51(B)**, which restricts Edison-base plug fuses to replacement-only applications to prevent over-fusing—a common cause of electrical hazards. This ensures your installation meets regulatory requirements while maintaining safety. - **Fast-Acting Protection:** Engineered to interrupt fault currents quickly, the TOO01.8 minimizes downtime and reduces the risk of equipment damage during overload or short-circuit events. This is essential for protecting **small motors, lighting circuits, and branch wiring** in both industrial and commercial settings. - **Universal Compatibility:** The Edison-base design allows for direct replacement in existing sockets, eliminating the need for costly rewiring or adapter kits. This makes the TOO01.8 a cost-effective solution for maintenance teams upgrading or repairing legacy systems. - **Durable Construction:** Constructed with high-quality materials, the TOO01.8 resists corrosion and mechanical stress, ensuring long-term reliability in demanding environments. Its robust design is ideal for **harsh industrial conditions**, where reliability is non-negotiable. - **Trusted Manufacturer Reliability:** Littelfuse, a global leader in circuit protection, designs the TOO01.8 to meet rigorous industry standards, including **UL 198E** and **CSA certification**. With decades of expertise, Littelfuse is the preferred choice for professionals who demand **precision, safety, and performance** in their electrical protection solutions. **Typical Applications:** The TOO01.8 Plug Fuse is widely used in **general lighting circuits, small appliance circuits, and fractional horsepower motor protection** across multiple industries. Common applications include: - **Commercial Buildings:** Office spaces, retail stores, and schools where lighting and small power circuits require reliable overcurrent protection. - **Industrial Facilities:** Manufacturing plants, warehouses, and maintenance workshops where legacy Edison-base fuse panels are still in use. - **Residential Retrofits:** Homes with older electrical systems that require replacement fuses without system upgrades. - **HVAC Systems:** Protection for small motor loads in heating, ventilation, and air conditioning units where fast-acting response is critical. - **Machine Tools and Equipment:** Safeguarding control circuits and auxiliary components in industrial machinery. **Installation and Selection Considerations:** When selecting a plug fuse like the TOO01.8, professionals prioritize **ampere rating, voltage rating, and interrupting rating** to match the circuit’s requirements. The TOO series is available in a range of ampere ratings (typically 15A to 30A), allowing for precise protection tailored to the load. Always verify the **NEC compliance** of your installation—Edison-base fuses like the TOO01.8 are restricted to replacement-only use, while Type S fuses (with adapters) are required for new installations to prevent over-fusing. Littelfuse’s reputation for innovation and reliability makes the TOO01.8 a standout choice for engineers, electricians, and facility managers. Whether you’re maintaining an existing system or ensuring compliance in a retrofit project, the TOO01.8 provides the **safety, simplicity, and performance** you need. Trust Littelfuse to deliver circuit protection solutions that keep your operations running smoothly—**safely and efficiently**.
  • Edison-base design with metal threads for standard lamp base compatibility
  • NEC-compliant for replacement-only applications (prevents over-fusing)
  • Fast-acting overcurrent protection for general circuits and small motors
  • Durable construction for long-term reliability in industrial/commercial use
  • Trusted Littelfuse quality with UL 198E and CSA certification

Specifications

Application
General purpose circuits and small motor loads
Brand Name
Littelfuse
Connection Type
Edison-base screw
Material
Metal
Mounting Type
Screw-in
Series
TOO Series
Special Features
Metal threads
Sub Brand
TOO Series
Type
Time Delay Fuse
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO020

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO009

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
The National Electric Code now permits Edison-base fuses to be used only for replacements in existing installations, and then, only when there is no evidence of overfusing or tampering. All new Edison-based fuseholders must have Type S fuse adapters installed before they are placed in service. Designed to prevent installation of wrong size fuses, Type S Adapters (SAO series) screw into Edison-base fuseholders so they may accept Type S fuses. Once installed the adapters cannot be removed. To prevent shunting of open fuses or overfusing, and to reduce nuisance fuse opening, it is recommended that SAO adapters with properly rated SLO or SOO series fuses be installed in all Edison-base fuseholders.

SAO1.25

The National Electric Code now permits Edison-base fuses to be used only for replacements in existing installations, and then, only when there is no evidence of overfusing or tampering. All new Edison-based fuseholders must have Type S fuse adapters installed before they are placed in service. Designed to prevent installation of wrong size fuses, Type S Adapters (SAO series) screw into Edison-base fuseholders so they may accept Type S fuses. Once installed the adapters cannot be removed. To prevent shunting of open fuses or overfusing, and to reduce nuisance fuse opening, it is recommended that SAO adapters with properly rated SLO or SOO series fuses be installed in all Edison-base fuseholders.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO02.5

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO05.6

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases.Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TLO030

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases.Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO012

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO03.5

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO014

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO007

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO002

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.
Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

TOO010

Littelfuse Plug fuses provide overcurrent protection to general purpose circuits and small motor loads. Edison-base Plug fuses (TOO and TLO series) feature metal threads similar to incandescent lamp bases. Type S Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and must be used with Type S adapters (SAO series). The National Electrical Code permits Edison base Plug fuses to be used for replacement purposes only. Type S fuses and adapters prevent shunting open fuses and over-fusing.

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.