Protecting your investment

The most functional, easiest to use, and most innovative control equipment is useless unless it's sheathed in a protective cover. Protection of this sensitive, often fragile equipment may be just as vital to the control engineer as the function they are designed to perform. Now, control equipment is performing in more and more harsh environments, and beside the contaminants they encounter...

By Michael Drakulich, assistant editor July 1, 1999

Enclosure Trends

NEMA specifications for protection



The most functional, easiest to use, and most innovative control equipment is useless unless it’s sheathed in a protective cover. Protection of this sensitive, often fragile equipment may be just as vital to the control engineer as the function they are designed to perform. Now, control equipment is performing in more and more harsh environments, and beside the contaminants they encounter, they’re also susceptible to such environmental factors as shock, vibration, and even ice damage.

Control Engineering recently learned more about the perceptions and attitudes of readers who specify, recommend, and/or buy enclosures and enclosure accessories. CE conducted a survey, randomly polling 1,500 readers to find answers to such issues as:

What protection codes respondents specify most, whether they are national, local, or industrial;

What features are most important when respondents specify enclosure components and accessories; and

What ergonomic factors buyers consider when choosing enclosure components.

Three-hundred thirty responded to the survey questionnaire, resulting in a 22% response rate. Nearly all that responded, 98%, specify, recommend, and/or buy enclosures and/or enclosure accessories.

Of the 98% that specify, recommend, and/or buy enclosure equipment, 72% do it for in-plant requirements, 21% say it’s for OEM requirements, while 5% say it’s for both.

Raw materials processing is the most represented industry segment, according to survey results. Over half, 52.5%, say their company’s primary end product is raw material. Manufacturers of machinery and equipment for manufacturing and service industries came in second with 27%. Manufacturers of instrumentation and control equipment, and automotive and other transportation equipment manufacturers tied for third, both with a 5.3% share of the votes.

What users need

National and international organizations have developed rating systems to standardize enclosure performance. For nearly every type of environmental condition there is a corresponding rating within one of these organizations’ systems. Respondents look to NEMA’s (National Electrical Manufacturers Association) rating system the most when specifying protection requirements. In fact, NEMA takes the top four spots in the survey. When choosing enclosures, respondents specify NEMA 4 (52%) most often, a slight edge over NEMA 12 (51%). NEMA 4X comes in with 34% of the votes, while NEMA 1 has 22%.

IEC/IP 56 is specified by 3% of the respondents and IEC/IP 55 is specified by 2%; perhaps this isn’t so surprising since IEC/IP standards are recognized in Europe, whereas NEMA is mostly recognized in North America. Other specifications accounted for 5% of the votes (for a complete list of what each of these specifications entails, see CE , March 1999, p. 166, or visit . Results exceed 100% due to multiple responses).

Doug Franz, industrial market segment manager for Hoffman (Anoka, Minn.), says NEMA 12 enclosures are an established, mature segment of the enclosure market. NEMA 12 enclosures from Hoffman have been one of the company’s top sellers for over a decade. But he says the segment to really watch is NEMA 4X. He predicts the market share for NEMA 4X enclosures will continue to rise as enclosures are installed in corrosive environments with more frequency.

In addition to codes designed to protect components inside the enclosure, users also need to specify safety codes to ensure everything and everyone outside the enclosure is protected from hazards such as fire and electrical shock. Enclosures may have to meet an array of standards as mandated by national, local, or industrial authorities. Users are also asked to work in several different types of environments. To account for the variety of standards and application types, the survey asked what three safety codes respondents most often specify; 59% say NEC (National Electrical Code) is consistently in the top three. Fifty-seven percent say NEMA is most often in the top three codes they must specify, while 32% say UL (Underwriters Laboratories) is.

Other codes respondents rank in the top three are: NFPA (National Fire Protection Association), 20%; ANSI (American National Standards Institute), 19%; OSHA (Occupational Safety & Health Association), 19%; IEC (International Electrotechnical Commission) 15%; and CE Mark, 13%.

Narrowing their choices even further, respondents singled out NEC, with 33% of the votes, as the code they most often specify. Again NEMA (32%) came in a close second. In third place is UL (Underwriters Laboratories) with 9%.

What users want

Most of all, make the enclosures affordable say the survey’s respondents. The survey asked them to pick the five most important features when specifying enclosures. Seventy-two percent of the respondents say low-cost is one of the top five features, more than any other feature in the survey. Availability, which was the top choice in CE ‘s 1998 Enclosure study (see CE , July 1998, p. 127), came in a close second with 67% of the votes. In third place is construction material, which 46% of the respondents consider as one of the five most important enclosure features.

Other features mentioned, along with the percentage of votes in the top five are: safety, 43%; maintainability, 40%; variety of accessories, 34%; ergonomics, 20%; modularity, 18%; expansion, 15%; design assistance, 12%; and OEM modifications.

Though cost received the most votes in respondents’ top five, availability, construction material, and safety tied for the most votes as the most important factor when specifying enclosures, each with 15%. Cost came in a close second with 14%. No other feature accounted for more than 10%, though maintainability received 7% percent of the votes.

Customization is also very important to respondents. Because of customization’s broad nature, it was broken down into several segments for this survey question: variety of accessories, modularity, expansion, and OEM modifications. All of the segments received substantial support from respondents, and OEMs agree.

Mike Murphy, product manager-industrial enclosure systems for Rittal (Springfield, O.) says customization is really on the rise. ‘We try to drive the customers to buy standard, cataloged enclosures,’ he says, but a large percentage of them really need the customization.

Jerry Stephani, OEM marketing manager for Stahlin (Belding, Mich.) says his company is working overtime for things users need such as specialized cutouts, colors, doors, and other similar requests. In fact, to ensure a swift turnaround, he says the company has had to restructure work shifts to accommodate requests for cutouts alone.

In addition to accommodating various customization requests, Stahlin also has its FastRight program to ensure that all enclosures rated as ‘type A’ in Stahlin’s catalog are shipped within 24 hours.

Hoffman combines customization and short lead times with its Modification Services program. The company says it can meet a wide variety of specifications, whether they be wall-mounted or large enclosures, in lead times as short as one to four weeks.

The survey also asked respondents about their top three ergonomic considerations when they specify enclosures. Easy access to internal components was the runaway favorite, both as the top choice, and the number of votes in the top three. Thirty-seven percent of the respondents say it’s their most important ergonomic consideration, while 72% say easy access one of their top three ergonomic considerations.

Easy-opening doors and panels follows with the second most votes in the top three with 53%, and mounting options comes in third with 38%. Footprint (36%), security (21%), viewing angles (19%), and height (13%) were also mentioned.

As the most important ergonomic factor, footprint followed easy access to internal components in second place with 16%. Easy opening doors is third with 11%, while mounting options is fourth (7%). Security and viewing angles tied for fifth as the most important ergonomic factor with 5% each.

Enclosure Products

For more information on enclosure products, visit .

Replacing steel with fiberglass

Belding, Mich. -Type 3 Series control enclosures are designed to house electrical, electronic instrumentation, and mechanical controls where front and rear access are desired. These units are constructed of compression molded, fiberglass-reinforced polyester with a memory-retaining, continuous silicon door gasket. Strut-mounted interior panels are made of aluminum, and they’re removable. All hardware is made of 300 series stainless steel.


Datacom cabinets

Anoka, Minn. -Proline DataCom cabinets house data and communication equipment, and network file servers. Proline cabinets are available in 22 frame sizes and can be configured as stand-alone enclosures, or used together for greater capacity. Each UL Type 1 rated DataCom cabinet is available with a range of external components such as doors, sides, covers, tops, and bases. Louvered components are available for ventilation. The cabinet window door features a black perimeter ventilation screen and a lockable, flush-mounted pop-up latch.


Mobile PC enclosures

Racine, Wis. -QCS7000SS mobile PC enclosure is constructed of stainless steel, acrylic, and polystyrene. Targeted toward such food processing applications as dairies and breweries, QCS7000SS is said to be ideal for applications where frequent washdowns occur, and corrosion of metal parts is a problem. Computer cabinet and monitor enclosures provide a secure location for valuable electronic equipment such as CRTs, CPUs, printers, and keyboards. The monitor enclosure adjusts in 3 axes and rotates for easy viewing.


Cooler to replace fans

Springfield, O. -Vortex Kooler cooling systems use compressed air to cool electrical enclosures. They are said to be well-suited to cooling small to medium-sized enclosures where heat loads are 2,500 BTU/hr and below. They are able to cool below the ambient temperature, maintain a NEMA 4/4X or NEMA 12 enclosure protection category, and reduce the maintenance requirements typically associated with air conditioners and filter fans. The Vortex Kooler product offering includes systems from 400 BTU/hr to 2,500 BTU/hr cooling capacity, with most models featuring either a UL 12 or UL 4X listing #E191061.


Wall-mounting cabinets

Elkridge, Md. -CAB PC family of wall mounted cabinets is built from corrosion-resistant polycarbonate (PC). UL listings include 4, 4X, 12, and 13. These units are also rated IP65. All CAB PC units have an enclosure flammability rating of UL94-5V, and offer an optional swing out door, an opaque or smoke transparent cover, quick release latches on the long or short side, and a latch or key-lock door. A wide range of sizes is available that can be machined, painted, and marked to meet custom requirements.


Enclosures for NEMA 4, 12 areas

York Haven, Pa.- 0140 Series enclosures are specifically designed for dirty, wet, or washdown areas. This enclosure can hold a desktop PC with up to a 21 in. monitor. It’s built with continuous weld seams for improved strength. Monitor shelf height is adjustable, and large front and rear access doors are latched for easy cleaning. An add-on keyboard drawer enclosure (pictured) allows a keyboard and pointing device protection from the environment without compromising the protection integrity of the upper enclosure. Several cooling options are available.

Daisy Data

Structure Combines Power and Control

Pittsburgh, Pa. -Integrated Facilities Systems (IFS) is a custom-designed approach to combining power distribution and control functions with environmental controls into a single, space-saving structure. IFS is said to solve problems associated with conventional equipment, such as the need to design around multiple suppliers’ in-stock inventory; excessive space required for several structures; increased installation time, labor costs and wiring expenses; and programming. IFS structures are prewired, preprogrammed, and tested per customer specifications and arrive on site ready to install.