Most electrical workers with some experience know that pests can quickly infiltrate and destroy electrical components inside control enclosures. Pests such as rats, snakes, and small insects will take over a control-housing unit because it provides them with protection from the weather and predators. Damage from pests in a control enclosure has been known to cause very costly fires or total production shutdowns. Failure of the panel could have been prevented with a little education on pest behavior and proper enclosure specification.
Common Pest Behavior: Rats/Mice: According to a study conducted by Rentokil: 49% of businesses report electrical damage caused by pests. Rats are especially damaging because they chew on electrical wires: “Rats have a pair of continuously growing incisor teeth in both their upper and lower jaw. As a result, they have to continuously gnaw on objects to wear them down and prevent them from becoming too long.” View the report at: https://www.rentokil.com/blog/rats-the-worlds-most-destructive-pest/#.WtOTHdPwZsM.
According to the Internet Center for Wildlife Damage Management, rats and mice can: Run along or climb electrical wires, pipes, fences, poles, ropes, cables, vines, shrubs, and trees to gain entry to a building; Climb almost any rough vertical surface, such as wood, brick, concrete, weathered sheet metal, and many plastic products; Crawl horizontally along or through pipes, augers, conveyors, conduit, underground utility and communications lines; Gnaw through a wide variety of materials, lead and aluminum sheeting, window screens, wood, rubber, vinyl, fiberglass, plastic, and low-quality concrete or concrete block.
Businesses in which food is stored or handled are especially prone to rodent invasion. Good sanitation practices are essential. Keeping food well sealed is very important. Reference: http://icwdm.org/handbook/rodents/RodentExclusion.asp.
Snakes: Snakes often enter electrical boxes for food similar to rats and mice. A snake’s climbing ability makes it easy for them to slither up and down electrical conduit. Once they enter the control box they are large enough to get shocked by the controls. Once shocked, all that will remain is the snake’s dead carcass and electrical controls that no longer operate. In 2017, a snake entered a substation and knocked out power for 22,000 customers in the Jacksonville, Florida area.
Ants: According to Texas Cooperative Extension, College Station, Texas: “Electrical workers must be aware that ants will nest in enclosures. What makes them especially dangerous is that they will defend their colony. These defense acts by ants can become a real physical threat to electrical personnel. Ants also tend to build nests with soil. The soil will corrode components, thus, causing control failure. Ants, like rats, will chew on wires and cause controls to fail.” https://fireant.tamu.edu/files/2013/02/FAPFS011_2007rev.pdf
Bees and Wasps: Bees and wasps find small openings, allowing them entry into electrical enclosures. The challenge is how to eliminate them without getting stung. According to the Michigan State University Extension -Department of Plant, Soil and Microbial Sciences: “Killing off a wasp nest is tricky business. As many of us know, the occupants of these nests tend to resist any effort to kill them by stinging the daylights out of those attempting to do so. During August, when the colony reaches its maximum size of worker wasps. The maximum size of the nest depends on the species: paper wasps may only produce a few dozen workers while colonies of yellow jackets may reach one or two thousand. The larger nests of yellow jackets and bald-faced hornets that are protected by a papier-mâché type material are more challenging and best left to pest control professionals.” http://msue.anr.msu.edu/news/getting_rid_of_wasps_nests
Prevention: To prevent damage to electrical controls, the staff needs to make sure the building, environment, and controls are secure from pests. Pests are experts at finding even the littlest of openings no matter if the controls are outside or inside.
Pests that find their way into a building’s structure will have access to all passageways for cables, pipes, and conduits that are integrated into the walls and ceilings, making them often hard to find and eliminate.
By inspecting the building’s foundation, conduit, pipes, outlets, water spigots, gaps at the base of a door, and windows that are not caulked properly, you can prevent pests from entering.
Properly fill any openings with pest-proof materials such as concrete, galvanized sheet metal, wire mesh, aluminum, copper, stainless steel wool, and other materials.
Having clean hands during the installation is very important especially after eating because food smells on the wiring will attract pest into the control housing. Keep all food items in secure containers and away from controls.
Specification of the control enclosure: While everyone is cost-conscious, choosing the least expensive electrical components, such as enclosures, is not always in your best interest. It is wise to make sure to properly select an enclosure that has been designed to protect against intrusions. There are lots of enclosure options such as materials, ratings, and hardware.
Process facility designers with the opportunity to select their material should investigate and determine the selections that are appropriate in the intended environment. Every application has its unique demands, and many performance capabilities are inherent in certain material choices.
However, an errant or over-estimated material choice can have many repercussions in the life cycle of a product. It makes good sense to select a product that is sufficient across the board.
Metallic enclosures: Stainless steel and other premium metal materials can be used where long life, corrosion resistance, and weatherability are critical. Keep in mind due to the higher cost of stainless steel enclosures compared to some other material options it is important to consider the environment the stainless steel enclosures will be placed. Even though stainless steel is corrosion resistant some environments such as coastal saltwater areas or chlorine exposure could still cause early failure of the enclosure. Lower grades of carbon steel can also corrode in harsh environments faster. Lastly, steel has high strength but exhibits low toughness, meaning it dents easily.
Non-Metallic enclosures: Fiberglass and polycarbonate material options have several advantages. These options are easy to modify (simple to drill cutouts), properly protect controls in harsh environments, is non-conductive, and withstands extreme cold/ heat. These enclosures are also cost effective.
Ratings: The NEMA (National Electrical Manufacturers Association) standards for enclosures indicate the amount of protection they are designed to provide. NEMA’s full standards can be found here: https://www.nema.org/Products/Documents/nema-enclosure-types.pdf
The seal of the NEMA 4X enclosure is designed to provide a degree of protection to the equipment inside the enclosure against an ingress of solid foreign objects (windblown dust) and provides a degree of protection with respect to harmful effects on the equipment due to ingress of water (rain, sleet, snow, splashing water, and hose directed water). Thus, an enclosure with a well-designed sealing solution will prevent the intrusion of even the smallest pests.
Electrical enclosures are also often put into harm’s way in commercial and industrial environments, especially in environments such as warehouse or outdoor work areas where accidental damage due to collision with heavy machinery, equipment, vehicles, and vandalism are often a daily occurrence.
The internationally recognized IK rating will help specifiers to determine if the enclosure is rated to withstand impact in these environments, so they will not eventually make it easy for pest to enter the housing. IK ratings are defined as IKXX, where “XX” is a number from 00 to 10, indicating the degree of protection provided by electrical enclosures against external mechanical impact. The higher the number will indicate more protection, with an IK10 being the highest rating available.
Robroy Enclosures patent material formulation is the main reason the enclosure stood up to IK testing. Robroy Enclosures patented SolarGuard compound ensures every enclosure manufactured in the Belding, Michigan, factory is rugged and durable in environments where exposure to impact is imminent.
After reviewing the many available enclosure options, an increasing number of companies that require secure protection from pest are choosing non-metallic enclosures.
For more details, please visit: www.RobroyEnclosures.com.