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Littelfuse SAO020 - 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 SAO020 The National Electric Code now permits Edison-base fuses to be used only for…

Alternate Item Number: 0SAO020.Z

UPC: 079458400717

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Overview

The NEC now restricts Edison-base fuses to replacement use only in existing installations, mandating Type S adapters for new installations. The SAO020 screws into standard Edison-base fuseholders, creating a permanent, tamper-proof interface that accepts only correctly rated Type S fuses. This prevents the dangerous practice of inserting improperly sized fuses, which can lead to overfusing, equipment damage, and fire hazards. This adapter is rated for 125 Vac and features an interrupting rating of 10 kA rms symmetrical. It is UL Listed to standard 248-11. The SAO020 is specifically designed to accept only 20 Ampere rated Type S fuses, preventing nuisance fuse openings and enhancing electrical safety. For optimal performance and safety, it is recommended to pair the SAO020 adapter with properly rated SLO (medium time-delay) or SOO (dual-element time-delay) series Type S fuses. Key Specifications: * Voltage Rating: 125 Vac * Interrupting Rating: 10 kA rms symmetrical * Approvals: UL Listed 248-11 * Accepts Fuse Ratings: 20 Ampere only The Littelfuse SAO020 is an essential component for electricians, facility managers, and maintenance professionals upgrading older electrical infrastructure to meet modern safety codes. It provides a cost-effective and reliable solution for enhancing electrical system protection in industrial, commercial, and institutional facilities. Manufacturer SKU: SAO020.
  • Accepts only 20 Ampere rated Type S fuses
  • 125 Vac voltage rating
  • 10 kA rms symmetrical interrupting rating
  • UL Listed 248-11
  • Designed to accept Littelfuse SLO or SOO series Type S fuses for optimal protection.

Specifications

Application
General purpose circuits and small motor loads
Brand Name
Littelfuse
Material
Poly
Mounting Type
Screw-in
Series
SAO
Special Features
Feature metal threads
Sub Brand
SAO Series
Type
Plug Fuse Adapter
Package Weight (Imperial)
0.029 L
Package Weight (Metric)
0.013 kg
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.

SAO6.25

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.
Mersen plug fuses are intended for industrial and residential applications. Non time-delay fuses are available for receptacle and lighting circuits and time-delay fuses for motor loads. For Canadian requirements, a type P fuse is used for non-motor loads and Type D, for electrical heating and cyclical load circuits. Both fuses have low melting-point temperature elements. Type S plug fuses are time-delay and tamper resistant. 125 Volts 15 Amps GP series. 125 Volts 20 Amps GT series.

GT20

Mersen plug fuses are intended for industrial and residential applications. Non time-delay fuses are available for receptacle and lighting circuits and time-delay fuses for motor loads. For Canadian requirements, a type P fuse is used for non-motor loads and Type D, for electrical heating and cyclical load circuits. Both fuses have low melting-point temperature elements. Type S plug fuses are time-delay and tamper resistant. 125 Volts 15 Amps GP series. 125 Volts 20 Amps GT series.
SOO Fuses are dual-element time delay Type S fuses designed for motor and motor branch-circuit protection; also suitable for all general purpose circuits.

SOO.400

SOO Fuses are dual-element time delay Type S fuses designed for motor and motor branch-circuit protection; also suitable for all general purpose circuits.
SLO Fuses are medium time-delay Type S fuses for general-purpose branch-circuit protection.

SLO020

SLO Fuses are medium time-delay Type S fuses for general-purpose branch-circuit protection.
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.

SAO015

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.
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.

SAO030

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.
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.

SAO005

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.
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.

SAO008

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.

Frequently Asked Questions

Where can I find in-depth training courses on Littelfuse products?

In-depth training courses and quick references for Littelfuse products can be found at the award-winning Littelfuse University (LFU) website.

What kind of technical support does Littelfuse Techline offer?

The Littelfuse Techline offers technical support for fuse and relay products, including product cross-references, general technical information, engineering drawings, and application assistance.

What types of fuses does Littelfuse offer for industrial applications?

Littelfuse offers UL Class fuses, high-speed fuses, medium voltage fuses, 10 x 38 mm fuses, and solar fuses for industrial applications.

What do Littelfuse pump controllers protect against?

Pump controllers protect and disable a pump if a hazardous condition arises, with options for single-phase and three-phase applications.

How do ground-fault protection relays work?

Sensitive ground-fault relays use advanced filtering to quickly detect insulation resistance breakdown caused by moisture, vibration, chemicals, or dust.

What is the function of trailing-cable protection relays?

Trailing-cable protection relays continuously monitor the integrity of the ground conductor in portable cables to protect equipment from hazardous voltages.

How can distributors display their inventory on Littelfuse.com?

Distributors can participate in the Stock Check Program to display their inventory levels directly on Littelfuse.com with a link back to their website.

What is the MROplus™ program designed to help manufacturing facilities with?

The MROplus™ program helps manufacturing facilities save money by reducing inventory and downtime while improving safety and productivity.

What are Littelfuse fuse blocks and holders designed for?

Littelfuse fuse blocks and holders are selected by OEMs and designers for their compact designs, indication features, and DIN-rail mounting flexibility.

What is the purpose of POWR-BLOKS power distribution blocks?

POWR-BLOKS power distribution blocks provide a safe and convenient method for splicing cables and managing power distribution requirements within panels and systems.

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.