Take control: Play it safe with the help of enclosures

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On the surface, the structure of an electrical enclosure seems basic. Get involved in selecting one; however, and the power, place, and parts of this humble component takes on new dimensions.

The sheer volume of heat-generating electronics in the market has made industrial control panels and enclosures integral to electrical engineering. These specially fabricated and machined cabinets are a conduit for distributing voltages between circuits, ensure critical equipment provide a lifetime of service, protect auxiliary components from damage and, emphatically, keep personnel out of harm’s way.

What’s the code?
The starting point for specifying electrical enclosures in industrial applications is to have knowledge of the protection system or the codes and standards applicable to the geographic location of the industrial user. These standards ensure high quality and reliability.

In general, electrical enclosures in North America require UL approval, with an emphasis on the type of rating, as shown on the rating plate. In Canada, enclosures and cabinets that house electrical equipment are listed with NEMA (National Electrical Manufacturers Association), UL (Underwriters Laboratories) and/or CSA (Canadian Standards Association) ratings.

NEMA enclosure type ratings set standards for electrical enclosure safety and reliability by specifying the performance criteria for enclosures based on the environment the enclosure is intended for. The ratings cover such criteria as the degree of protection against water and dirt, mechanical impact, or oil and corrosion resistance.
Keep in mind that NEMA does not test products. Both UL and CSA use NEMA guidance for the investigation and listing of their electrical enclosures. Only once tested can enclosures carry a NEMA, UL or CSA label. Differences amongst these ratings may depend on whether the equipment was third party tested or whether standards were left in the hands of the manufacturer.

Form factors
Enclosure manufacturers take great care to define precise requirements with respect to materials (stainless steel, aluminum, zinc, galvanized steel, or polycarbonate), positioning and mounting (free-standing or wall-mounted) options, distance from other assemblies and climate control. These instructions must be observed, along with regular quality inspections, otherwise the warranty may be voided in the event of a malfunction or damage.

For insights into selecting an electrical enclosure that has as its objective a solution for both protecting equipment and guarding against arc flash conditions, André Bousette, president, Rittal Limited, Canada, suggested we look at the company’s isolation enclosure solution, which helps engineers design the ideal system for their application with arc flash prevention in mind. The Flange Mount Disconnect Enclosure, for example, meets Requirement 66.1.3 from the UL508A Standard for industrial control panel construction.

A simple mechanical interlock solution with robust safety considerations can function to prevent an operator from opening a power enclosure while the system is energized. The logic behind a simple principle that all doors must be closed to power the system on, is as follows:

• The connecting door interlocking kit provides the means to lock the connecting door while the main door is closed and the power is on. It also prevents the main door from closing while the connecting door is open and unsecure.
• The interlock activator allows the activator kit to work properly by latching and unlatching connecting doors when required.
• The adapter plates ensure compatibility with most commercially available operator handles and allow upgrades and modifications without performing additional cut outs in the field, all while maintaining Type 12 rating. (A type 12 NEMA rating is intended for indoor enclosures without knockouts. They provide a degree of protection to personnel against access to hazardous parts, and protects the enclosed equipment inside against ingress of dirt, dust, and fibres).
• The defeater lever provides safety locking between most common operator handles, enclosure and door. Assembly is simple with just two screws while the door is open. The activator bracket synchronizes the enclosure door latch with the operator handle. This allows the enclosure to be powered on only when the door is latched, and lock the internal doors in the event the main door is unlatched. (This lever is factory installed.)
• The connecting rod connects the defeater lever to the activator bracket and provides simple adjustments for the adapter plate and operator handle selected. This allows quick and easy installation with the flange door open.

Future-proofing power management
At Hannover Fair 2023, Markus Asch, CEO, Rittal International and Rittal Software Systems touted at a high level the benefits of smart production in the context of efficient processes that can be adapted to individual customer needs.

“Innovation that goes beyond products and solutions is needed,” said Asch. “We need to understand the various processes surrounding our customers’ value chains, consider new ecosystems and develop overarching solutions.”

To understand the full impact of how hardware and software work to streamline complex engineering processes and integrate safety, “we have to look at the global ecosystem around manufacturers like Rittal,” said Roland Younk, president, Eplan Canada. “These manufacturers provide hardware—components that all must work together in any given automation and control system. Their daily business relies on the precision of the customer’s BOM (bill of materials). This BOM must be 100 per cent before manufacturing starts to insure a proper workflow.”
Younk explained that during the early days of engineering, customers must be aware of all technical details of all parts involved in the design.

“Eplan’s design and engineering software provides over 1.4 million parts and provides access to more than 245 manufacturers via the data portal,” said Younk. “Here, not only commercial data is handled for the BOM, but also technical data as well as 3D connection data is carried along. I said carried along because once the BOM is forwarded for the sourcing of the parts, the game continues. Manufacturing and operations still require more smart data. The software will be using the rest of the carried data to calculate the precise length of all wiring required. The fact that the length is now known means extra wire pre-fabrication machines can be used, such as the WT Terminal from Rittal.”

The software is what allows manufacturers to use initial data along the process chain. All users—including the engineer, designer, purchasing, mechanics, and electricians—have visibility on the initial data provided and continue adding value. “At Rittal and Eplan we like to call it the added value chain,” said Younk. “It means engineering, sourcing, manufacturing, and operations are all served through data coming from the same and unique engineering software.”

Robust safety assessments
In today’s industrial environment, where safety is closely tied to precision and error-free performance, manufacturers are increasingly reliant on complementary areas of expertise.

Plants may link technology and data to process design and operational assets to derive insights from a single source of truth and drive improved performance through risk assessments and standard operating procedures based on the operating environment.

In some cases, a low-tech enclosure is all it takes to do the job. In others, future-proofing will require secure and protected equipment and controls through edge solutions. Either way, developing integrated safety training programs can save an arm and a leg.