This section provides an overview for circuit protectors as well as their applications and principles. Also, please take a look at the list of 30 circuit protector manufacturers and their company rankings. Here are the top-ranked circuit protector companies as of November, 2023: 1.NOARK Electric North America, 2.Erickson Electrical Equipment Co., 3.Great Valley Industries, Inc..
A circuit protector is a power disconnect device for instrumentation. The word "circuit" refers to an electric circuit. Therefore, the literal translation of circuit protector is "electric circuit protector," and it is used for this purpose.
Instead of being low capacity, circuit breakers are characterized by a faster disconnection speed than general low-voltage breakers. Due to this feature, they are mostly used for protection of control circuits and instrumentation circuits. They operate before low-voltage breakers installed on the primary side to protect the upper circuits.
Circuit protectors are used in instrumentation and control circuits. Measuring equipment for industrial applications, such as differential pressure transmitters and electromagnetic flowmeters, are called instrumentation, and the circuits used to supply power to the instrumentation and receive and transmit signals are called instrumentation circuits. Instrumentation circuits are characterized by low power consumption in spite of their high importance among industrial devices.
Circuit protectors can be used to protect the upper circuits while minimizing the effects of instrumentation circuit malfunctions. Control circuits are electrical circuits that control the power and heat sources of industrial equipment.
Large industrial motors are controlled to run and stop by electromagnetic contactors, and other drive devices. Although large motors consume oversized amounts of power, the power consumption used to control the drive device tends to be small.
However, the control circuit is of high importance because any abnormality in the control circuit will cause the industrial equipment to lose control. The use of a circuit protector minimizes the effects of a control circuit error.
Circuit protectors in general use are divided into parts such as trip coils, contact parts, casings, and handles. The trip coil is the part that breaks the circuit by opening the contacts with the magnetic force of the electromagnetic coil in the event of an overcurrent. It is used in the disconnecting mechanism of circuit protector because it has a more immediate response than the bimetal.
The contact part is a metal part that actually conducts electricity to the circuit, and when the contact part opens, the circuit is interrupted. Copper or silver alloys are used as materials. The casing is the outer frame of the circuit protector and is made of insulating resin. It insulates the contacts from the drive spring and mounting bracket.
The handle is an interface component that allows human operation. The handle and spring turn the contacts on and off to control the conductive disconnection. Most circuit protectors are equipped with a trip-free function.
The trip-free function is a function that gives priority to overcurrent trips and opens the contacts even when the handle is locked in the "on" position. This is one of the main functions of a circuit protector and improves the reliability and safety of circuit breakage.
Circuit protectors are used in instrumentation and control circuits; they are not often used as circuit breakers for 3-phase power motors.
The first step is to check the number of phases in the circuit. Most instrumentation and control circuits are single phase, so select a 1-phase or 2-phase circuit protector.
While a 1-phase circuit protector saves space and is more economical, it does not completely interrupt the circuit. Therefore, use the phase with 0 V to ground voltage as the common phase (common wire); if both phases do not have 0 V to ground voltage, be sure to select a 2-phase or more circuit protector.
A 3-phase circuit protector is used in circuits that indicate 3-phase voltage, such as a voltage indicator. Rarely, they are also used as circuit breakers for small 3-phase motors.
Once the number of phases has been determined, check the current rating of the equipment to be connected to the secondary side; if two or more units are connected, the total value should be used as the rated current, and a circuit breaker with a capacity greater than the rated current should be selected.
If a circuit protector is selected with less than the rated current, there is a high risk of tripping during normal use. Since control and instrumentation circuits are often of high importance and frequent tripping is uneconomical, select a circuit breaker with sufficient capacity.
Circuit protectors for industrial equipment are often manufactured by Mitsubishi Electric Corporation in Japan. Ltd. is a specialized manufacturer of FM circuit breakers, which are circuit breakers for wiring.
The company also designs and manufactures related parts such as earth leakage circuit breakers, protectors for electrical equipment protection, current limiters, various power supply devices, and, in an unusual twist, garbage disposers.
Tyco Electronics Japan also manufactures Circuit Protectors, which are sold by Asahi Giken Kogyo. Eaton Electric Japan Corp. also sells circuit protectors.
It is a wholly foreign-owned company and its birthplace is Germany, where electrical control technology was born in 1899. The former company name Muller, with over 100 years of experience since its establishment, became a member of Eaton Gr in the U.S. in 2008. Eaton Electric Japan established its Japan office in 1974, and has been providing customer support in Japan for over 45 years since then.
Circuit protector is available at Monotaro, an online retailer, for as low as one dollar. Many circuit breakers are made by major Japanese electronics manufacturers, such as Mitsubishi Electric and Fuji Electric, and are readily available parts unless they are special products.
*Including some distributors, etc.
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ABB Motors and Mechanical Inc., founded in 1920 and with headquarters in the USA, is a custom manufacturer and marketer of industrial electric motors, drives, and mechanical power transmission products. The company's products include AC/DC, gear, synchronous, variable speed servo motors, and permanent magnet motors produced in over 20 plants across North America, China, and Mexico for the HVAC, chemical, food and beverage, oil and gas, and wastewater industries, among others. ABB Motors and Mechanical Inc. also holds an ISO 9001:2015 certification.
Erickson Electrical Equipment Co. is a manufacturer of utility metering products, founded in 1932, and headquartered in Elk Grove Village, Illinois. They offer type CM group metering (modular) in both 240V and 480V, current transformer section with the disconnect in both 240V and 480V and current transformer cabinets. They also offer ground detectors, termination boxes, and accessories. Their products are used for accurate metering of electrical services, serving several sectors, including commercial, industrial, and residential.
Addison Building Materials was founded in 1947in Arlington Heights, Illinois. Addison has over 38,000 items in stock across departments including lumber, building materials, hand tools, power tools, electrical, fastener, paper products, SOG Knives, janitorial, clothing, ice & snow, automotive, and audio-visual departments. In addition, Addison offers various services including custom orders, local delivery, rental program for contractor and industrial tools and equipment, lumber cutting, pipe threading, and paint color matching.
Federal Radio and Television, now known as Federal Electronics, was founded in Providence, Rhode Island, in 1948. They were established by Romolo Evangelista and initially sold and maintained electric machinery and appliances. Federal Electronics is now an Electronic Manufacturing Services (EMS) supplier with offices in Rhode Island and Mexico. They engage in electronic contract manufacturing that is adaptable and configurable. Their services include but are not limited to, fiber optic interconnects, box builds, and systems integration.
Pollak Corporation was established in 1909 as a tool and die shop in Boston, Massachusetts. In 2019, Pollak Joined Standard Motor Products and expanded its product offerings. Today, Pollak provides custom design, test, and manufacturing for automotive, agricultural, construction, and marine-related industries. In the company’s ISO 9001/QS9000 certified facilities, the company advances customer requests from the concept stage through testing, initial production, and all the way to volume production. The company’s existing customers include Ford, General Motors, PACCAR, John Deere, and Caterpillar.
Marshall DC Lighting (MDL) is an American supplier of LED lighting solutions established in 2017 and based in Phoenix, Arizona. The company stocks various direct current (DC) LED light products, including standard, remote and off-grid lighting, as well as fixtures and utility items like exit signs. They operate as a partner to Nextek Power Systems, which is a national pioneer of DC-powered systems and technologies. MDL serves the lighting needs of in-state public utility companies, as well as client companies like Cox Communications, DuPont, and Lowe's.
Twittlebit.com is located in Lexington, Kentucky. Twittlebit is a distributor of industrial equipment and components divided into 8 sub-stores including: sensors, HMI & PLC, visual & audio , panel components, and pneumatic & vacuum. The company offers next day delivery to Kentucky and neighboring states, and 2-to-3-day delivery to most other states of in-stock products. The company offers in-stock selection of many top brands such as Autonics, EEControls, Panasonic, and Cembre. The company can also in-source many hard to find products directly from Japan from companies such as IDEC, Canon, Omron, and Fuji Electric in 7-to-10-days.
Dietz Electric was founded in 1974 and is based in Milwaukee, Wisconsin. Dietz Electric is a broad-line stocking distributor offering electric motors, drives, and power transmission products. Dietz Electric also offers customization options to test, manufacture, modify, and repair all product offerings. Product offerings include electric motors, hazardous locations motors, custom electric motors, variable frequency drives, motor controls, power transmission solutions, and specialty items such as purge systems, Uras vibrators, disc brakes, transformers, and AC line reactors.
Shamrock Controls is a division of Burns Controls Company, an industrial distributor of hydraulic, pneumatic, and automation products. Burns Controls Company was established in 1971 in Dallas Texas. Shamrock Controls is a global distributor of IEC electrical motor controls and factor automation solutions. Shamrock Controls product listings include contractors, overload relays, DP contractors, relays, push buttons, pilot lights, control stations, motor starters, circuit breakers, disconnect switches, cam switches, power supplies, terminal blocks, cable glands, lock nuts, din rails, ducts, wire accessories, and various pneumatic components.
Wenzhou DAQUAN Electric Co., Ltd was founded in 1996 in Wenzhou, China. The company is an electrical products manufacturer of relays, relay sockets, timers, meters, and related components to customers both in and outside of China and serves both home appliance customers as well as industrial customers in manufacturing and other industries. The company has 5 major product segments including relays, timers, meters, circuit breakers, and switches. The company also sells various tools, alarm devices, and product accessories.
Siemens began in 1847 and is headquartered in Munich, Germany. Siemens focuses in automation and digitalization technology and operates globally. Siemens’s 5 operating segments are digital industries, smart infrastructure, mobility, Siemens Healthineers, and Siemens Financial Services. Siemens Financial Services provides debt and equity investment as well as financing solutions. Siemens Healthineers is a medical devices company that provides products and consulting. Mobility includes passenger and freight transportation. Smart infrastructure includes full solutions for electrification. Digital industries offer both software and hardware for industries and production efficiency.
Mitsubishi Electric was established in Japan in 1921 and headquartered in Tokyo. The company’s Semiconductors & Devices division is a manufacturer of products serving several industries ranging from home appliances and automotive to renewable energy and optical fiber communication. The company’s products are divided into 4 product segments: power devices, high-frequency devices, optical devices, and infrared sensors. Power devices encompass motion controls, most home appliances, and SiC applications. High-frequency devices include satellite communications systems, radios, and base transceiver stations. Optical devices include projector light sources and optical fiber communication. Infrared sensing systems include MeIDIR thermal sensors.
ETI is a manufacturer of electrical protection and control products based in Slovenia, Central Europe where it was established in 1950. The company deals in circuit breakers and switches along with enclosures, distribution boards, and equipment ETIBOX. The company is also known for manufacturing transformers, contractors, fuses, and control devices. These products are installed as integral solutions for the protection of electrical equipment and components in residential and commercial buildings, in the field of electric power and industry electrical installations.
Hoisden Corporation, founded in 1950, is a manufacturer and retailer of electronic components based in Kitakyuhoji, Japan. The products include transducers, electromechanical components, acoustic components, and wireless components. The transducers are speakers, receivers, microphones, and touch sensors, whereas the electro-mechanical components include HDMI connectors, USB connectors, miniature jacks, detector switches, and remote control units used in telecommunication, healthcare, home, and amusement industries. The company runs an OEM, ODM, and EMS contract and production service department, collaborating with the customer to plan, design and produce products according to their desired design or specifications.
SWEETA was established in 1995 and is headquartered in New Taipei City, Taiwan. SWEETA is a manufacturer of switches, AC sockets, and circuit breakers globally. Most products have been certified to meet international safety standards such as UL, CSA, VDE, and others. SWEETA has an extensive product line. A few listings include AC sockets, plug adapters, switches, thermostats, and test tweezers.
E-T-A, founded in Bayern, Germany, in 1948 is a manufacturer of overcurrent protection, power distribution, relays and intelligent systems. The company's product portfolio includes thermal-magnetic devices as well as magnetic and hydraulic-magnetic circuit breakers, battery isolation switches, power entry modules, and solid state relays and intelligent systems. The company serves industries such as Oil and Gas, Aerospace and Defense, Automotive and Transportation, Construction, and Power Generation. They have 4 production sites and operate in more than 60 countries.
Sang Mao Enterprise, since 1984, is a manufacturer of circuit overload protection components including temperature switches & control fuses, circuit breakers, and leak-proof temperature sensors based in Tainan City, Taiwan. Their circuit breakers are square, round, or toothless fixed heads or fixed frames with automatic return, manual reset, and shaking return types. The company also manufactures 1-inch and ¾ inch single and three-phase motor protectors. Sang Mao has passed ISO 9001:2015 certification and is UL, CCC, CSA, TUV, and VDE-approved. Their products are used in household appliances, automotive equipment, pumps & motors, and business machinery, including medical equipment, transformers, and industrial instruments.
The SCHURTER Company was founded in 1933 and operates out of Lucerne, Switzerland. SCHURTER is an innovator and producer of electronic components for many markets including industrial equipment, medical equipment, automotive, avionics and space, data and communication, and energy. SCHURTER products and solutions include: circuit protection, connectors, switches, EMC, custom components, HMI solutions, PCAP touchscreens, resistive touchscreens, capacitive switches, membrane switches, and a series of smart products including Smart Connector DS11 PEM, Smart Connector DT31 external, and Smart Ecosystem.
Carling Technologies, founded in 1920 in Connecticut, USA, is a circuit breaker and switch manufacturer. The company specializes in the design, development, and manufacturing of advanced switches and control products. Their comprehensive product line comprises of toggle switches, rocker switches, push-button switches, rotary switches, and circuit breakers. These products are crucial for managing electrical systems, keeping operations secure, and regulating power distribution. They are used in various industries, such as automotive, marine, aerospace, industrial, and telecommunications. The company also offers customized, advanced solutions for marine technology, including power regulations for vessels of any size and circuit protection.
TE Connectivity Ltd., started in 2007 and headquartered in Schaffhausen, Switzerland, is a designer and manufacturer of sensor and connectivity solutions for harsh conditions. It operates three primary segments, namely transport, industrial, and communication solutions, and its product portfolio includes automotive connectors, fiber optic connectors, analog power meters, RTD sensors, and circuit breakers. It serves customers in approximately 140 countries and several industries, including aerospace, automotive, rail, IoT connectivity, and E-mobility. The company manufactures 192 billion products annually and has invested over 610 million USD in research development and engineering.
Crouzet was founded in 1921 and is headquartered in France. The company is an independent manufacturer of mechatronic components for applications in the aerospace, energy, building, and machinery industries. The company offers four primary product categories: Switches & Sensors, Aerospace, Motion, and Automation & Control. Aerospace includes cockpit controls, electrical protection, and various position sensors. These are designed to increase pilot comfort and improve flight safety. Motion includes motors, actuators, and external control electronics. Automation & Control includes both hardware and software solutions.
NOARK is based in Pomona, California, and is a global manufacturer of low-voltage electrical components for industrial applications. NOARK specializes in motor controls and protection for original equipment and manufacturers with products covered by five-year limited warranties. NOARK parts are used in numerous solutions such as HVAC and refrigeration, industrial food equipment, panel builders, digital storage, and engine generators. NOARK’s main product lines include low-voltage power circuit breakers, molded case circuit breakers, miniature circuit breakers, overload relays, and circuit control devices.
Fuji Electric Equipment Control was established in 2008 in Saitama-ken, Japan is a manufacturer of power distribution and control equipment. The company boasts an extensive and diversified product portfolio including motor controls, MV distributors, energy control equipment, LV distributors, and industrial control relays. These products find applications in construction as magnetic contactors, automotive as manual motor starters, home appliances as air circuit breakers, health care devices as sensors and switches, and in environmental management for quality assurance and protection of high-voltage electric power and management of low-voltage consumption rate.
Rockwell Automation, Inc. was founded in 1903 and is headquartered in Milwakee, WI. Rockwell Automation provides industrial automation and digital transformation solutions around the world. Rockwell Automation operates through their intelligent devices, software & control, and lifecycle services segments with both hardware and software products and services. The Intelligent Devices segment offers drives, motion, safety, sensing, industrial components, and configured-to-order products. The Software & Control segment provides control and visualization software and hardware, information software, and network and security infrastructure solutions. The Lifecycle Services segment provides consulting, professional services and solutions, and connected and maintenance services through independent distributors.
American Electrical was founded in 1997 and is based out of Richmond, Virginia. The company is a distributor of DIN rail-mounted components and electrical equipment to customers in the US as well as overseas. The company offers 3 product segments: Connection, Protection, and Wire Preparation. The connection segment includes terminal blocks, PCB terminal blocks, IR modules, and DIN rails. The Protection segment includes products such as circuit breakers and surge arrestors. Wire Preparation offerings include wiring ducts, wire ferrules, and tools.
Hybrid Electronics is a global distribution specialist of electronic components, with access to over 50 million unique components. Among the markets HE serves are the aerospace, automotive, communications, defense, industrial, medical, national security, and test & measurement industries. In addition to components, HE also provides quality and compliance testing, counterfeit detection, upscreening, and other forms of quality control. Examples of component subtypes that HE offers include ICs, batteries, capacitors, semiconductor products, sensors, circuit protection, interconnectors, filters, optoelectronics, relays, switches, power supplies, and cables and cable assemblies.
AutomationDirect.com was founded in 1994 to provide solutions for the industrial automation market and has been growing its list of offerings ever since. AutomationDirects’ extensive catalog includes individual components such as cables, various controls, I/O devices, relays, gauges, fittings, and sensors to complete systems. Many parts and devices, especially PLC units are customizable. AutomationDirect.com also provides support via video instructions, online manuals, a learning library, an active community forum to further assist customers.