Extreme Connecting: Hazardous Situations Demand
Interconnects That Perform Even In Worst-Case Scenarios
By Lynda Nolen, Bishop & Associates Inc.

Over the last two decades, the use of connectors in industrial applications has increased tremendously. Along with this surge in usage and demand has come a need for connectors designed specifically to operate in extremely hazardous environments—even in catastrophic conditions, such as an explosion or fire. Various regulations and certifications have been established to regulate the use of electronic/electrical equipment in these types of environments and eliminate, minimize, or control the potential they might have to ignite the atmosphere.

There are three basic ways that electronic and electrical equipment can be a potential source of atmospheric ignition. Heat generated by the equipment can cause the surface of the equipment to become hot, which in turn heats the surrounding air, raising the potential of fire. Arcs or sparks generated by the normal operation of the equipment is also a risk factor. The third situation that raises fire risks is the electrical shorting of a terminal. Based on where the equipment is located, specific regulations governing product design and use have been established to prohibit or reduce the chance of any of these three situations occurring. These regulations are often referred to as Ex or Explosion-proof certifications, and are based on a variety of criteria, including location or zone, temperature, and type of material (gas, solid, or liquid).

Numerous environments and applications require explosion-proof or Ex certification. These consist of areas where flammable liquids, vapors, gases, or combustible dust, fibers, or flyings are present, and include:
 

Over the years, a number of recognized certifications for the operation of electrical/electronic equipment in hazardous environments have been established. Two of the more prominent are ATEX and IECEx. ATEX (often commonly referred to as Directive 94/9/EC) stands for ATmosphere Explosive, and refers specifically to equipment manufactured for use in hazardous areas. Developed in Europe in the 1990s to allow open trade among European member unions, ATEX provides technical and legal guidelines for both the manufacturer of the equipment and the user. Effectively a law in all union countries, ATEX is a mandatory directive in Europe that can only be provided by EU certification agencies. Today, along with regional and national certifications, including NEMA, UL, and CSA, ATEX certification is not only recognized and accepted in Europe, but is also often accepted by equipment installers and operators in many other countries, including North America.

IECEx (International Electrotechnical Commission Explosive) certification, which was developed with the objective of having one international certificate, thus permitting the unrestricted sale of products worldwide, was initiated in the late 1990s. Unlike ATEX certification, IECEx certification not only covers equipment, but also the repair and overhaul of existing equipment.

Both ATEX and IECEx certification demonstrate that a sample of the manufacturer’s explosion-proof connector has been independently tested and complies with the standards associated with the certification. Certification also demonstrates that the facility used to manufacture the connectors has been audited and found to meet the appropriate quality system requirements. There are a variety of organizations that can provide certification, and IECEx and ATEX certification can be issued at the same time, using the same test reports. Many of these test reports can also be used to obtain national certification, such as UL, CSA, BASEEFA, or KEMA.

Although many equipment installers and users will accept either certification, Dean W. Nagy, director business development oil and gas-Pyle products at Amphenol Industrial Operations, explains, ”IECEx is becoming the certification of choice because it will not only be accepted in Europe but most everywhere around the world. The ATEX certification is really going to mean nothing within the next couple of years. In fact, we have customers that are now requiring IECEx certification, and will not use your product if all you have is ATEX. IECEx is also the most versatile of the certifications, and although ATEX has been accepted outside of Europe, now with IECEx becoming the choice, ATEX is losing favor in many areas.”

When determining the appropriate Ex certification, there are a series of steps manufacturers and users must take. These steps, vary depending on the certifying agency, such as ATEX or IECEx. They include group, zone, class, type of protection, and temperature. Further classification separates the gases from the dust, and specifies the level of ingress protection (IP). In the U.S., hazardous location descriptions are based on the National Electrical Code (NEC). In Canada, the Canadian Electric Code description is used, while Europe and much of Asia rely on guidelines established by the International Electrotechnical Commission (IEC). There are two primary equipment groups—equipment used in underground mining operations, and equipment used in other areas where the potential for an explosive atmosphere exists. In the U.S., the mining industry is not regulated by the NEC, but rather by the Mine Safety and Health Administration (MSHA).

Products used in applications not involving mining fall under zones 1 or 2 for gases, and zones 21 or 22 for dust; groups IIA, B, or C for gases, and groups IIIA, B, or C for dusts. The charts below provide a brief description of hazard location categories.

Although a number of manufacturers produce various types of electrical/electronic components for use in hazardous environments, Amphenol Industrial has been a key connector manufacturer of explosion-proof approved products for many years. Their flagship series, Star-Line EX®, is a hybrid form of their proven Star-Line series and a preferred source for geophysical and petrochemical applications, including top drive drilling systems, FPSO buoy and mooring systems, AC drive systems, BOP controls, and pumps and monitoring systems for land and offshore. Designed for use in power, control, and instrumentation applications, the heavy-duty Star-Line EX series can be terminated onto unarmored or armored and sheathed cable built to IEEE-45/UL1309, IEC, BS, DIN, and JIC standards, and has a vast array of reversible inserts for power, signal, and mixed applications. Globally recognized for use in explosive atmospheres, the Star-Line EX is available in contact sizes ranging from single-contact to 143 contacts, and in wire gauges from 18 through 777MCM. The Star-Line EX series is ATEX and IECEx certified for Zone 1-11C, has an IP68 rating, and offers double-lead Acme threads that provide complete coupling in one turn of the coupling nut.

In addition to Star-Line EX, Amphenol Industrial also manufactures Amphe-EX. The newest connector in their line of explosion-proof connectors, the Amphe-EX, is an IP68-rated, miniature threaded cylindrical connector specifically designed to allow a signal to pass through zone rated areas, using coax, and fiber optic cables, as well as standard copper. “The primary difference between the Star-Line EX and Amphe-EX is the size and the current carrying capabilities. Star-Line EX is more for power and multi-pin applications over 16 AWG wire sizes, and Amphe-EX is for the smaller wire sizes, coax, and fiber optics,” said Nagy. Reducing the space required for the connectors, the Amphe-EX series is approved for Zone 1 rated applications and ATEX, IECEx, and AEX certified. In addition to copper, coax, and fiber optic cable, Amphenol Industrial is also currently designing an RJ45 series connector, which will allow use of Ethernet Class D/Cat 5e cable, and they hope to have a USB version completed by year’s end. “The RJ45 and USB could be used anywhere, most of our current customers use them for programming of equipment in hazardous areas and downloading of data in Zone 1 areas,” added Nagy.

To facilitate fast delivery of Amphenol IECEx and ATEX approved products, Amphenol Industrial has established a worldwide network of distributors. One of these distributors, PEI-Genesis, is recognized for their ability to assemble and delivery connectors in as little as 48 hours and is certified to supply the entire Amphenol Industrial explosion-proof offering. The Star-Line EX series, which is assembled in their U.K. facility, carries the same ATEX certification as if purchased through Amphenol Industrial direct.

In order to maintain ATEX/IECEx certification, Amphenol Industrial has all of their distributor partners audited by SIRA Testing and Certification every 12-18 months. “This allows them to ship our product with certified ATEX/IECEx labels,” said Nagy.

Although these products are designed for a niche market, it’s a market that has been growing yearly, particularly in regions like China, the North Sea, and the United Arab Emirates. Explosion-proof connectors from a certified supplier are essential to installer and operator safety, as well as to reduce maintenance and downtime of the end product.

Although most mil-spec-approved connectors are designed for used in harsh environments, it is important to differentiate between connectors designed and manufactured for harsh environments and ones manufactured for hazardous environments. Nagy said, “There are major differences between a mil-spec-approved connector and one that is, for instance, ATEX approved. ATEX-approved connectors all have to have approved flame paths; these would be all the threaded joints. ATEX-approved products have to be able to contain an explosion internally, if gases that it’s rated for get inside the connector and explode. ATEX-approved products all have temperature limits that they cannot exceed at full load, based on the gases that they are tested to. Most Mil-DTL spec products do not have the mechanical strength to qualify for any type of hazardous application.”

Fueled by higher oil and gas prices, the desire to embed control and communications features into these products, and the addition of sensors for machine diagnostics, it is anticipated that the requirement for explosion-proof certified electronic/electrical connectors will continue to grow over the next decade. A good indication of this growth is also seen in the number of additional connector manufacturers who also offer certified products. Today, in addition to Amphenol, others offering explosion-proof, certified connectors and connector accessories include ITT Cannon, Cooper Industries, Bulgin, Glenair, Cavotec, Stahl, and Gisma.

Lynda Nolen Director of Databases, Regions-Products-Markets, Bishop & Associates Inc. Lynda Nolen has been in the interconnect industry for over 30 years. She has worked in sales, sales management, marketing, and product management for such companies as TRW Electronics Components Group, Sunbelt Components, Cinch Connectors, Arrow Electronics, PEI Genesis, and Delphi Interconnect. Nolen has extensive experience in competitive cross-referencing, drawing, web and catalog review, new product introduction programs, harness and connector assembly programs, account management, and customer service programs. Lynda received her Bachelor of Arts degree from Roger Williams University in Rhode Island in 1979, and has completed various electrical engineering courses.