Littelfuse PHS120A10 - The PHS120A10 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 10 A; inrush of 100 A.
Littelfuse

PHS120A10

Alternate Item Number: PHS120A10

UPC: 079458997781

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Overview

The **Littelfuse PHS120A10 Phase Control Relay** is a high-performance, variable voltage phase angle control relay engineered for precise industrial protection and load management. Designed to handle demanding applications, this relay delivers a **120VAC input voltage** with a **steady-state rating of 10A (100% on)** and an **inrush capability of 100A** (non-repetitive for 16ms), making it ideal for systems requiring robust current handling during startup or transient events. With a **voltage drop of approximately 2.0V at rated current**, the PHS120A10 ensures minimal power loss while maintaining operational efficiency. **Key Features & Technical Specifications:** - **Phase Angle Control:** The PHS120A10 utilizes **variable voltage phase angle control**, allowing for smooth and precise regulation of AC loads. This technology is critical in applications where gradual power delivery reduces stress on connected equipment, such as motors, heaters, or lighting systems. - **High Inrush Handling:** With an **inrush rating of 100A**, the relay excels in environments where high initial currents are common, such as motor starting or capacitive load switching. This capability prevents nuisance tripping and extends the lifespan of downstream components. - **Wide Input Tolerance:** The relay supports an **input voltage range of 120VAC ±20%**, accommodating fluctuations in power supply without compromising performance. It is also compatible with **230VAC systems**, offering versatility for global applications. - **Compact & Durable Design:** Measuring **50.8mm x 50.8mm x 38.4mm (2" x 2" x 1.51")** and weighing approximately **3.9 oz (111g)**, the PHS120A10 is designed for space-constrained installations. Its **surface-mount design** with a single #10 screw ensures secure attachment, while **0.25-inch (6.35mm) male quick-connect terminals** simplify wiring. - **Environmental Resilience:** Operating reliably in temperatures from **-20°C to 60°C** and storing between **-40°C to 85°C**, the relay is built to withstand harsh industrial conditions. It also features **95% relative humidity tolerance (non-condensing)**, ensuring consistent performance in humid or variable environments. - **Safety & Protection:** The PHS120A10 includes **dielectric breakdown protection ≥2000V RMS** (terminals to mounting surface) and **insulation resistance ≥100MΩ**, meeting stringent safety standards for industrial applications. For relays rated **≥6A**, Littelfuse recommends bolting to a metal surface using included heat sink compound to maintain a maximum mounting surface temperature of **90°C**. **Typical Applications & Industry Use Cases:** The PHS120A10 is a versatile solution for a broad range of industrial and commercial applications, including: - **Motor Control & Drives:** Ideal for variable speed drives, conveyor systems, and pumps where phase-controlled power delivery enhances efficiency and reduces mechanical stress. - **Heating Systems:** Suitable for resistive heating elements, ovens, and furnaces, where precise voltage regulation improves energy efficiency and temperature control. - **Lighting Control:** Used in dimming systems for incandescent, halogen, or LED lighting, providing smooth transitions and reducing flicker. - **Power Distribution & Automation:** Integrates seamlessly into PLC-based control systems, motor starters, and automated machinery for reliable load switching and protection. - **Renewable Energy Systems:** Can be deployed in solar inverters, wind turbine controllers, and battery management systems to manage phase-aligned power delivery. **Why Choose Littelfuse for Phase Control Relays?** Littelfuse is a globally recognized leader in circuit protection, switching, and control solutions, with a reputation for innovation and reliability. The **PHS Series**, including the PHS120A10, reflects the company’s commitment to delivering high-performance relays that meet the rigorous demands of industrial automation, power distribution, and motor control. With decades of expertise, Littelfuse ensures that its products undergo rigorous testing for durability, safety, and performance—giving engineers and technicians confidence in their long-term reliability. **Installation & Maintenance Considerations:** - **Mounting:** Secure the relay to a flat, grounded metal surface using the provided screw and heat sink compound (for ≥6A ratings) to dissipate heat effectively. - **Wiring:** Use **0.25-inch quick-connect terminals** for easy and secure connections. Ensure proper insulation resistance for line voltage applications. - **Adjustment:** The built-in **potentiometer** allows for fine-tuning of output voltage, enabling customization for specific load requirements. For 120VAC systems, a **100KΩ potentiometer rated at 1W** is used, while 230VAC systems require a **200KΩ, 2W potentiometer**. - **Compliance:** The PHS120A10 meets industry standards for dielectric strength, insulation resistance, and environmental resilience, ensuring compatibility with global regulatory requirements. **Conclusion:** For engineers and procurement professionals seeking a **reliable, high-performance phase control relay**, the **Littelfuse PHS120A10** stands out as a cost-effective solution for demanding industrial applications. Its combination of **high inrush handling, precise phase control, and robust construction** makes it an essential component in motor drives, heating systems, lighting controls, and power distribution networks. Backed by Littelfuse’s legacy of quality and innovation, the PHS120A10 delivers the performance and durability required to protect critical equipment and optimize operational efficiency.
  • Variable voltage phase angle control for precise load regulation
  • 10A steady-state rating with 100A inrush capability (16ms non-repetitive)
  • 120VAC input with ±20% tolerance; compatible with 230VAC systems
  • Compact 2" x 2" design with surface-mount capability and quick-connect terminals
  • Dielectric strength ≥2000V RMS and insulation resistance ≥100MΩ for safety

Specifications

Brand Name
Littelfuse
Connection
Surface mount with one #10 (M5 x 0.8) screw
Connection Type
0.25-inch male quick-connect terminals
Current Rating
10 A
Mounting
Surface mount with one #10 (M5 x 0.8) screw Mount
Mounting Type
Surface-mount with single #10 screw
Operating Temperature
-20 to 60 F
Operating Temperature, Maximum
60 F
Operating Temperature, Minimum
-20 F
Series
PHS
Size
50.8mm x 50.8mm x 38.4mm
Special Features
10Y WARR
Standard
UR/CSA
Sub Brand
SSAC
Voltage Rating
120 VAC
Package Dimensions (L x W x H)
1.51 IN x 2 IN x 2 IN
Package Dimensions (L x W x H)
38.4 mm x 50.8 mm x 50.8 mm
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First) FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FA155-2

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First) FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The PHS120A6 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.

PHS120A6

The PHS120A6 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.
The PHS120A20 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 20 A; inrush of 200 A.

PHS120A20

The PHS120A20 relay provides phase control protection with input voltage at 120 V ac and output load rating at steady state (100% on) of 20 A; inrush of 200 A.
The SCR series are Tower and Obstruction Lighting Controls used in a variety of applications. The SCR430T and SCR630T are universal lamp alarm relays designed to sense the failure of flashing or steady incandescent beacon lamps or steady side lights. The SCR9L is a universal lamp alarm relay designed to sense the failure of flashing or steady LED beacon lamps or obstruction lamps. The SCR490D Series is used to provide remote monitoring of steady burning incandescent marker and obstruction lighting. Four onboard switches allow operator programming for lighting systems with two through nine lamps on a single AC circuit. See the Technical Resource Section below for individual datasheets containing specifications and operation details.

SCR430T

The SCR series are Tower and Obstruction Lighting Controls used in a variety of applications. The SCR430T and SCR630T are universal lamp alarm relays designed to sense the failure of flashing or steady incandescent beacon lamps or steady side lights. The SCR9L is a universal lamp alarm relay designed to sense the failure of flashing or steady LED beacon lamps or obstruction lamps. The SCR490D Series is used to provide remote monitoring of steady burning incandescent marker and obstruction lighting. Four onboard switches allow operator programming for lighting systems with two through nine lamps on a single AC circuit. See the Technical Resource Section below for individual datasheets containing specifications and operation details.
The SIR2B20A4 relay provides solid-state switching protection with input voltage from 90 to 150 V ac/dc and output voltage at 120 V ac.

SIR2B20A4

The SIR2B20A4 relay provides solid-state switching protection with input voltage from 90 to 150 V ac/dc and output voltage at 120 V ac.
The FS200 Series may be used to control inductive, incandescent, or resistive loads. Factory fixed flash rate of 45 or 90 FPM or may be ordered with a fixed custom flash rate ranging from 10 to 180 FPM. Encapsulation provides protection against shock, vibration, and humidity. Uniform performance, high inrush current capability, and low RFI, make this series ideal for general industrial applications. Operation: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until input voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS224

The FS200 Series may be used to control inductive, incandescent, or resistive loads. Factory fixed flash rate of 45 or 90 FPM or may be ordered with a fixed custom flash rate ranging from 10 to 180 FPM. Encapsulation provides protection against shock, vibration, and humidity. Uniform performance, high inrush current capability, and low RFI, make this series ideal for general industrial applications. Operation: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until input voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The PHS230A6 relay provides phase control protection with input voltage at 230 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.

PHS230A6

The PHS230A6 relay provides phase control protection with input voltage at 230 V ac and output load rating at steady state (100% on) of 6 A; inrush of 60 A.
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS127

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The FS300 Series of solid-state flashers were specifically designed to operate lamp loads. Their two-terminal series connection feature makes installation easy. The high immunity to line noise and transients makes the FS300 Series ideal for moving vehicle applications. All solid-state construction means reliability and long life. The FS300 Series offers a factory fixed flash rate of 75 FPM or may be ordered with a fixed, custom flash rate ranging from 60 to 150 FPM. Operation: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until input voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS324

The FS300 Series of solid-state flashers were specifically designed to operate lamp loads. Their two-terminal series connection feature makes installation easy. The high immunity to line noise and transients makes the FS300 Series ideal for moving vehicle applications. All solid-state construction means reliability and long life. The FS300 Series offers a factory fixed flash rate of 75 FPM or may be ordered with a fixed, custom flash rate ranging from 60 to 150 FPM. Operation: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until input voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS126

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.

FS146RC

The FA and FS Series Flashers have proven their reliability through years of use on communication towers, smoke stacks, cooling towers, tall buildings, bridges and utility towers. The highest quality components are encapsulated in a rugged plastic housing with a molded-in heat transfer plate. The flash rate, ratio, and failsafe design meet FAA regulations. Zero voltage switching can increase lamp life up to ten times. The FS155-30RF & FS165-30RF include superior RF filtering circuitry for use in high RF installations, including AM hot towers. Operation: FS Series - Flasher (OFF First), FA Series - Flashers & Aux. Modules: Upon application of input voltage, the T2 OFF time begins. At the end of the OFF time, the T1 ON time begins and the load energizes. At the end of T1, T2 begins and the load de-energizes. This cycle repeats until voltage is removed. Reset: Removing input voltage resets the output and the sequence to T2.
The SCR series are Tower and Obstruction Lighting Controls used in a variety of applications. The SCR430T and SCR630T are universal lamp alarm relays designed to sense the failure of flashing or steady incandescent beacon lamps or steady side lights. The SCR9L is a universal lamp alarm relay designed to sense the failure of flashing or steady LED beacon lamps or obstruction lamps. The SCR490D Series is used to provide remote monitoring of steady burning incandescent marker and obstruction lighting. Four onboard switches allow operator programming for lighting systems with two through nine lamps on a single AC circuit. See the Technical Resource Section below for individual datasheets containing specifications and operation details.

SCR630T

The SCR series are Tower and Obstruction Lighting Controls used in a variety of applications. The SCR430T and SCR630T are universal lamp alarm relays designed to sense the failure of flashing or steady incandescent beacon lamps or steady side lights. The SCR9L is a universal lamp alarm relay designed to sense the failure of flashing or steady LED beacon lamps or obstruction lamps. The SCR490D Series is used to provide remote monitoring of steady burning incandescent marker and obstruction lighting. Four onboard switches allow operator programming for lighting systems with two through nine lamps on a single AC circuit. See the Technical Resource Section below for individual datasheets containing specifications and operation details.

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.