Smart Appliances Require Intelligent Interconnect
By Lynda Nolen, Bishop & Associates Inc.

Appliances as we once knew them are being transformed by new technology. And as familiar consumer devices utilize more electronics to monitor and control their operation, their interconnect systems need to keep pace.

The global market for cable assemblies used in consumer applications is expected to exceed $7 billion by 2015. A key industry within the consumer market is the appliance, or “white goods” industry. Encompassing major appliances we use daily, the white goods industry includes washing machines, dryers, refrigerators, microwaves, freezers, dishwashers, trash compactors, and ovens/ranges. It also includes smaller appliances, such as vacuums, coffee makers, mixers and blenders, and convection ovens.

These everyday products can easily be taken for granted until they are not working. But the connector industry has taken notice of the white goods industry, and has helped transform these devices with technology, pushing them beyond the mundane. Geared towards consumer convenience and safety, as well as the need to reduce energy consumption, much of this transformation has occurred because of the increased use of electronics, and in turn, cable assemblies.

Today’s consumers may already have appliances such as robotic vacuums and floor washers. It may not be long before the modern home also includes such appliances as refrigerated ovens, smart microwaves and dishwashers, and a wide variety of appliances with built-in repairmen. The refrigerated oven, for example, keeps food cold while you are away, and then becomes an oven, preparing your meal at the exact temperature you choose with a simple phone call or email command. With an additional call or email, the refrigerated oven will even keep your meal warm if you get stuck in traffic. The newest microwaves can automatically scan the UPC/barcode of packaged foods and select the correct time and cooking power to create a meal. Others use humidity-sensing technology to determine when the food is cooked. Smart dishwashers not only do the basic job of cleaning your dishes, but also can determine exactly how much detergent needs to be added, the proper cleaning cycle, and start time, basically doing everything but putting the dishes away for you. And it is no longer just the Maytag repairman who is lonely. A number of appliances, including washers, dryers, and dishwashers, offer a direct line to your repairperson, which allows them to analyze your appliance by phone and to find and fix the problem online.

Three key factors in the increased use of electronics in appliances are standardization, modularization, and communication. In the realm of standardization, the most influential connector system is the RAST system. Developed well over two decades ago in Europe as a way to standardize components and assemblies, assuring inter-mateability among manufacturers and reducing plugging errors, the RAST systems also reduces labor costs, which results in lower costs to the consumer and increased profits for the manufacturer.

RAST, as explained by Lee Thomas, Molex industry marketing manager – home appliances, “is the acronym for Raster Anschluss Steck Tecknik, roughly translated from German as ‘pitch connection plug technology.’ Controlled by the ZVEI (Zentralverbank Elektrotechnik–und Elektronikindustrie e.V, German Electrical and Electronic Manufacturers’ Association) committee, RAST connectors form the connection system for the multiple sensor, switch, actuator, and motor drive wires that connect to the control board.” Initially developed using a crimp-style contact where the wire was stripped, crimped, and snapped into a plastic housing, many of today’s RAST system components now incorporate an IDT contact that allows termination of the wire without stripping or crimping. Because the contacts are pre-assembled in the housing, there are fewer components to worry about and less chance of wires being inadvertently snapped into the wrong position, all advantages that broaden the RAST system’s industry appeal and its potential.

Developed around two contact pitch configurations, 2.50 (.098”) and 5.00mm (.200”), RAST connectors are available in a variety of versions, with multiple keying, coding, and locking options. For instance, as Thomas adds, “The Molex RAST line-up includes RAST 5 IDT and crimp for indirect mating in either 10 amp or 16 amp versions. RAST 2.5, for direct and indirect mating, and RAST Power, for direct and indirect mating, in both 6 amp and 10 amp versions. Optional polarizing ribs, color coding, side latches, and pip locks are offered throughout the range, along with open or slotted side walls on the RAST 2.5 and RAST Power.” To complement their range of RAST IDT and crimp connectors, Molex also offers a full range of mating headers in vertical and right-angle versions, as well as a “comprehensive range of application tooling, ranging from simple manual bench presses, ideal for prototype work, through semi-automatic tools to fully automatic machines capable of producing up to 18,000 terminated circuits per hour.”

In addition to thru-hole PCB-mount, many European manufacturers of RAST connectors also offer surface-mount versions. STOCKO Contact, the first company in Europe to offer surface mount RAST connectors, offers product made of DSM Engineering Plastic’s high performance Stanyl® For Tii™. Use of this high-performance material allows connectors to be assembled to the board by lead-free reflow soldering, reducing assembly time and cost while complying with RoHS requirements.

Modularization, the second key factor that has influenced the increase in electronics in appliances, is also supported extensively through the RAST system. As more features are added to an appliance, the number of connections increases, as each of these features must be connected to the control panel. Rather than using individual connectors and harnesses, RAST provides the ability to gang up connections, reducing the number of harnesses. Using both color-coded and uniquely keyed and polarized connectors, the RAST system not only reduces assembly time, but also reduces the chance of mis-wiring, and reduces the number of components a manufacturer has to keep in inventory.

In North America, it’s important to reduce the number of components that have to be stocked for repair of domestically manufactured products. Due to a lack of standardization, service centers that support repair requirements must carry a much wider breadth of inventory to satisfy multiple manufacturers. Lack of standardization is even more noticeable to the North American consumer when the required repair is on an appliance assembled in China or the Asia-Pacific region. Because of the broad number of manufacturers who supply components to the white goods industry, it is not uncommon for a consumer to wait weeks while a part is ordered and shipped from overseas.

Although the predominate usage of the RAST connector system is still primarily European-based, there are many signs indicating that as the benefits of the system become more apparent, adaptation by other countries will increase. According to Thomas, “The new global interest in the RAST system is based both on process improvements and cost savings. Automated IDT systems not only add speed to the wire harness assembly process, but also provide testing to lower the applied costs in the manufacturing process. As IDT typically uses an automated process, harness failures are significantly lower compared to manually built harnesses, which are normally crimp-and-poke-type systems. A harness failure can be extremely costly for a manufacturer when you consider the rework costs to replace a failed connector on a harness that is already loaded into an appliance.”

Better serving both their indigenous market and the international market is exactly what China-based Leoco is doing. One of the few Chinese connector manufacturers to offer RAST connectors, Leoco offers both the RAST 2.5 and RAST 5 connector systems. Primarily serving European-based customers, as pointed out by Claire Chang, sales director for Leoco USA, Leoco sells product and works extensively with Chinese-based contract manufacturers who are buying and assembling parts for European customers. Similar to other manufacturers of RAST connectors, Leoco’s RAST connectors are used in large and small appliances, HVAC applications, as well as anywhere control modules interface with sensors.

When dealing with manufactured equipment, especially equipment such as appliances that are geared primarily towards consumer use, being able to satisfy local safety standards is also very important. In North America, this means being able to satisfy UL and CSA standards, in particular UL94V-0. UL94V-0 evaluates the combustion of a particular item when brought in contact with a direct flame. In order to satisfy UL94V-0 requirements, a flame must be out in 10 seconds or less, no glow must be visible beyond 30 seconds, and no burning material can fall.

In Europe, this means not only being able to satisfy TUV standards, but also IEC 60335-1 fourth edition. IEC 60335-1 fourth edition, often referred to as the Glow-Wire European safety standard, is much more stringent than UL94V-0 requirements in that it covers both direct flame and indirect flames. As Thomas points out, “This certification is required on all home appliances sold in Europe. The Glow-Wire standard acts as protection against fire for unattended electrical household appliances. The test is designed to identify plastic materials that could ignite when wires are overloaded. To pass the test, a connector is submitted to a glow wire at 750ºC for 30 seconds. There can be no ignition or any flame must self-extinguish within two seconds. Molex RAST connectors meet the strict Glow-Wire European safety standard, as well as U.S. safety standards.” Chang also acknowledges the importance of satisfying the European Glow-Wire safety standard. “Yes, Leoco’s RAST products definitely all meet the Glow-Wire European Safety standard, in addition to being UL recognized, CSA certified, and TUV licensed,” she said.

Probably the easiest factor for the layperson to understand, yet one of the most challenging but influential factors, is the increase in communication, both to the consumer and to the appliance’s control modules. Just like you are able to instruct your computer to tell your printer what to print, how to print it, and when to print it, today’s Internet-enabled appliances can be programmed to start, stop, switch modes, or even entertain you, all while optimizing the performance of the appliance.

Other communication applications use sensors to determine time, temperature, humidity, and other variables. These have greatly influenced appliance development, allowing for a complete real-time diagnostic review of your appliance, not only solving current problems or issues, but also forewarning of future or potential problems.


Although many of these products have been around for years, widespread adoption is just beginning, influenced heavily by the proliferation of smartphones. And as smartphone capabilities also increase, so will the capabilities of our appliances. Just think, maybe someday they will come up with a way to not only dry your clothes at the perfect temperature setting, but also put them away for you!