What Struthers-Dunn does

Struthers-Dunn is a Timmonsville, South Carolina-based manufacturer of electromechanical and electronic relays founded in 1923 by John Struthers-Dunn. The company designs and produces relay products across ten primary categories — general purpose, traffic cabinet, power relays and contactors, motor reversing, latching/sequencing, special purpose, hermetically sealed, sensitive/low-input-power, timer/sensor, and reed relays — along with supporting accessories and sockets. Its core technology centers on electromechanical switching with proprietary design elements including the first plug-in relay with a built-in LED for normally-open contact status confirmation (2014) and the 87H and 88H Series, marketed as the first hermetically sealed plug-in relays to achieve simultaneous UL/CUL Class 1 Div. 2, ATEX, and IECEx Component Certifications for hazardous environments. The company is one of the last remaining U.S. manufacturers of power relays and contactors and maintains nuclear-qualified versions of its 219 Series and 236/237 time delay products for nuclear power plant applications.

The company generates revenue through direct hardware sales of relays and supporting sockets; pricing is not publicly disclosed and is handled via request-for-quote through authorized distributors or the manufacturer directly. Go-to-market is primarily channel-driven: an authorized distributor network that includes Master Electronics, RS Group, Universal Electronic Supply, Grainger, and McMaster-Carr in the United States, plus regional partners Electro-Sonic in Canada, Seratech in Singapore, Farnell Element 14 in the UK, and RS Group's Middle East portal for international coverage. Direct enterprise field sales handle custom relay design engagements for aviation, airport lighting, rail, and legacy/obsolescence replacement applications. Customer segments are horizontal across industrial end-markets — state DOT traffic signal cabinets, power generation and water/wastewater treatment, motor control (cranes, hoists, elevators, HVAC, electric vehicles), nuclear safety, oil and gas, and factory automation — with traffic and industrial controls identified as primary verticals.

Following its 2010 relocation to the current Timmonsville facility and the 2023 transition to 100% employee ownership, the company has executed a coordinated product refresh including the 2025 launches of the 450 Series Power Relay and the 87H/88H Series hermetically sealed families. Struthers-Dunn holds ISO 9001:2015 (re-certified July 2024), UL Client Test Data Program (CTDP) certification, ATEX and IECEx component certifications, and active memberships in the American Nuclear Society and the National Association of Manufacturers, providing the regulatory scaffolding required to serve safety-critical end-markets.

Name

Struthers-Dunn

Legal name

Struthers-Dunn, LLC

Website

https://struthers-dunn.com

Company type

Private

Founded year

1923

Operating status

Operating

Headcount range

11–50 employees

Short description

Struthers-Dunn is a 100-year-old, 100% employee-owned U.S. manufacturer of electromechanical and electronic relays serving traffic, power generation, motor control, nuclear, and industrial automation customers through authorized distributors and direct custom design sales.

Ownership category

akta.pro rank

Product category

Industrial Relays

NAICS

Relay and Industrial Control Manufacturing (335314), Switchgear and Switchboard Apparatus Manufacturing (335313), Electrical Equipment Manufacturing (33531)

SIC

Electrical Industrial Apparatus (3620), Switchgear & Switchboard Apparatus (3613)

akta.pro primary industry

Electromechanical Components (Relays, Switches, Potentiometers, Encoders) (IMAGAJAB)

akta.pro secondary industries

Circuit Protection Devices (MCBs, MCCBs, ACBs, fuses, RCD/GFCI, surge protection) (IMAGAEAB), Power Quality, Metering & Monitoring (HDACAJAG)

Keywords

• Electromechanical relays
• Industrial relay manufacturing
• Traffic cabinet relays
• Power relays contactors
• Hermetically sealed relays

Headquarters

HQ city

Timmonsville

HQ country

United States

HQ region

North America

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Operations, Supply Chain, Technology or R&D, Infrastructure, Marketing or Sales

Revenue model

1. Electromechanical Relays: Manufacturing and sale of electromechanical relays including general purpose, traffic cabinet, power, motor, latching/sequencing, special purpose, hermetically sealed, sensitive/low input power, timer/sensor, and reed relays
2. Electronic Relays: Manufacturing and sale of electronic relay solutions for industrial applications
3. Custom Design Relays: Custom-designed relay solutions for unique customer applications including aviation, airport lighting, rail industry, and other focused market segments
4. Accessories and Sockets: Sale of relay accessories and sockets including six, eight, and twelve pin sockets and plugs
5. Import Alternatives: High quality/lower cost import alternatives for certain products

Go-to-market motion3 records

Distribution channels10 records

Marketing channels4 records

Core offering

Struthers-Dunn designs and manufactures electromechanical and electronic relays and industrial controls for traffic signal cabinets, power generation, water/wastewater treatment, HVAC, motor control, nuclear power plants, and custom industrial applications. The company produces general purpose, traffic, power, motor, latching/sequencing, special purpose, hermetically sealed, sensitive/low-input, timer/sensor, and reed relays, along with supporting accessories and sockets. As one of the last remaining U.S. manufacturers of power relays and contactors, the firm emphasizes rugged, overbuilt designs with high reliability for demanding industrial environments.

Product overview

Struthers-Dunn is a manufacturer of electromechanical and electronic relays and controls serving the traffic signal, nuclear safety, power generation, industrial automation, and motor control markets. Founded in 1923, the company offers a comprehensive portfolio of relay products organized into categories including General Purpose Relays, Traffic Cabinet Relays (1-136 Series, 21H Series), Power Relays & Contactors (450 Series, PM Series, 575 Series, 645RT Series), Motor Relays (275 Series), Hermetically Sealed Relays (87H, 88H Series), Timer/Sensor Relays (286/287, 326/327, 388/388, 235, 236/237, 349 Series), and Special Purpose Relays. The company also produces custom-designed relays for aviation, airport lighting, and rail applications, and provides nuclear-qualified versions of several relay families. Accessories include various socket configurations for traffic cabinet integration. As one of the last remaining U.S. manufacturers of power relays and contactors, Struthers-Dunn emphasizes rugged, overbuilt designs with high reliability for industrial applications.

Differentiator

Problem solved

Functional benefit

Products and services

• General Purpose Relays Industrial general purpose relays for factory automation and control applications.
• Traffic Cabinet Relays Relays designed for traffic intersection signal cabinets, specified in NEMA, Caltrans, and ATC Style cabinets.
• Power Relays & Contactors Industrial power relays and contactors for power generation, motor control, and heavy-duty applications.
• Motor Relays Relays and contactors for motor reversing applications in cranes, hoists, elevators, HVAC, and electric vehicles.
• Latching / Sequencing Relays Relays with latching and sequencing capabilities for power control applications.
• Special Purpose Relays Custom-designed relays for unique applications including aviation, airport lighting, and rail industry.
• Hermetically Sealed Relays Hermetically sealed relays approved for hazardous locations including Class I, Div. 2, ATEX and IECEx certified environments.
• Sensitive – Low Input Power Relays Relays designed for low power input applications.
• Timer / Sensor Relays Time delay relays and voltage/current sensor relays for industrial control applications.
• Reed Relays Reed relays for various industrial and control applications.
• Accessories and Sockets Supporting accessories and sockets including six, eight, and twelve pin sockets and plugs for traffic cabinet components.
• 87H Series Hermetically Sealed Relays 5-Amp ice cube size 8 or 14 pin hermetically sealed relay with optional LED indication, Class I Div. 2, ATEX & IECEx approved for hazardous environments.
• 88H Series Hermetically Sealed Relays 10-Amp hermetically sealed relay approved for Class I, Div. 2 hazardous locations with ATEX & IECEx certifications.
• 450 Series Power Relay 40/50 Amp power relay with standard panel mount including optional DIN rail mount, power-on LED indicator, finger protective cover, rectified coil or suppression diode, blowout magnet, and auxiliary switches.
• 1-136 Series Flash Transfer Relays Flash transfer special purpose relays with stellar reputation for reliable and durable traffic control in NEMA, Caltrans, and ATC cabinets.
• 275 Series Motor Reversing Contactors Motor reversing contactors for industrial motor control applications including cranes, hoists, elevators, and HVAC.
• 219 Series Family Configurable relay family covering a wide range of contact combinations and coil voltages, including Time Delay 246/247, Latching 255, and Sequencing 311 Series. Nuclear qualified versions available.
• 21H Series Compact hermetically sealed design for new ATC traffic cabinets with variety of coil voltages for longer trouble-free life.
• 418 Series Hybrid Relay Hybrid relay designed to replace Mercury Displacement Relays in older traffic cabinets, handling loads up to 75 Amps as main power contactor.
• 428/429 Series Hybrid Main Contactor Hybrid main contactor designed for use in ATC traffic cabinets.
• PM Series Power Relays Industrial power relays for motor control applications in cranes, hoists, elevators, and HVAC.
• 575 Series Motor Reversing Relays Motor reversing relays for industrial power and motor control applications.
• 645RT Solid State Motor Reversing Series Solid state motor reversing relays for industrial applications.
• 286/287 Series Timer Relays Industrial time delay relays for power generation and control applications.
• 326/327 Series Timer Relays Industrial time delay relays for industrial control systems.
• 388 Series True-Off Timer Relays True-Off series timer relays for industrial applications.
• 235 Series Adjustable Current Sensor Adjustable current sensor relay for industrial monitoring applications.
• 236/237 Series Time Delay / Voltage Sensor Relays Adjustable voltage sensor and time delay relays, including nuclear qualified versions for power plant applications.
• 349 Series Over/Under Voltage Sensing Relay Voltage sensing relay for over/under voltage protection in industrial applications.
• Nuclear Qualified Relays Nuclear qualified versions of 219 Series and 236/237 Time Delay Series approved for use in Nuclear Power Plant applications.
• Custom Design Relay Solutions Custom-designed relay solutions for unique customer applications including aviation, airport lighting, rail industry, and competitor obsolescence replacements/retrofits.

Segments7 records

Ideal customer profiles5 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature7 records

Partnerships

Two partnerships are on record, tiered minor.

• NAM (National Association of Manufacturers)minorOthersCorporate membership in the National Association of Manufacturers, an industry association that advocates for manufacturing policy and provides industry resources.
• American Nuclear SocietyminorOthersMembership in the American Nuclear Society, an organization for professionals in the nuclear science and technology field, supporting the company's nuclear relay products.

Scale indicators4 records

Recent moves7 records

Expansion highlights5 records

Broad incumbents

• Omron Corporation: Japanese global manufacturer with a substantial industrial relay business (general purpose, solid state, power, PCB relays). Significantly larger and more diversified than Struthers-Dunn but directly competitive in factory automation relay sockets and panel-mount products.
• Eaton: US-based power management major with D series, P series, and other relay lines serving motor control, power distribution, and industrial automation. Competes with Struthers-Dunn on power relays and contactors and shares the US manufacturing footprint advantage.
• ABB: Global electrification and automation major with a broad relay portfolio covering contactors, motor protection, and interface relays. Competes with Struthers-Dunn in industrial panel builders and in oil & gas and power generation verticals.
• Schneider Electric: Global industrial controls major that previously owned the Magnecraft portion of Magnecraft & Struthers-Dunn. Offers overlapping relay and contactor products through its Zelio, TeSys, and Harmony lines, with comparable applications in motor control and industrial automation.
• TE Connectivity: Global electronics conglomerate whose Potter & Brumfield / Schrack relay lines compete directly with Struthers-Dunn in general purpose, power, and hermetically sealed relays. Much larger scale and broader portfolio but overlapping core relay products and industrial customer base.
• Panasonic Industry (Industrial Solutions): Division of Panasonic offering a wide range of electromechanical relays (signal, power, solid state) for industrial and automotive applications. Competes across the same general-purpose, power, and automotive/electric vehicle relay categories served by Struthers-Dunn.
• Phoenix Contact: German manufacturer of industrial connection technology, automation, and relay products including PLC interface relays and power contactors. Overlaps with Struthers-Dunn in industrial control cabinets and DIN-rail mounted relay sockets.

Direct peers

• Finder: Italian privately-held manufacturer specializing in relays and sockets for industrial applications. Closest direct comparable to Struthers-Dunn in product mix (general purpose, power, timer, PCB relays), niche specialization, and customer segment focus on industrial automation and panel builders.
• IDEC Corporation: Japanese manufacturer of relays, timers, and industrial control components with comparable product breadth in electromechanical and solid-state relays. Targets similar industrial automation and control panel customers and competes head-to-head in general purpose and power relay categories.

Others

• Magnecraft (acquired by Schneider Electric, legacy brand): Legacy relay brand now part of Schneider Electric's Harmony line following the 2005 acquisition of the Magnecraft portion of Magnecraft & Struthers-Dunn. Historically the closest competing commercial relay brand to Struthers-Dunn and still sells product lines with overlapping specifications.

Market position

Strengths5 records

Weaknesses4 records

Competitive moat4 records

Key highlights1 record

Customer concentration

Compliance6 records

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Struthers-Dunn