We are at the peak of what we here at EXAIR call Cabinet Cooler Season! Nothing can shut down an electrical cabinet and all the machinery its controlling faster than a 100° F + day and a non temperature controlled cabinet! EXAIR has a product that is controlled by the temperature in your panel so when those hot days come around it cools and protects your sensitive components. And shuts off conserving compressed air on the cooler days and months!
From right to left: Small NEMA 12, Large NEMA 12, Large NEMA 4X
One of our specialized applications are for Cabinet Cooler® Systems in areas with hotter than normal ambient temperatures. Sometimes electrical cabinets are located in environments near high heat sources such as boiler rooms, furnaces, ovens or other heat sources. If the ambient temperature is above 125° F (52° C) we offer a High Temperature Cabinet Cooler systems.
EXAIR High Temperature Cabinet Cooler systems offer relief for ambient temperatures ranging from 125° – 200° F (52°C – 93°C). Our Cabinet Cooler calculator found at https://www.exair.com/knowledgebase/cabinet-cooler-sizing-guide.html will automatically determine if the High Temperature cooler is required for your specific application.
Even in extremely aggressive environments, EXAIR Cabinet Cooler Systems provide reliable heat protection for your sensitive electronics and controls.
Heat within an electrical cabinet can be a major issue for manufacturing companies. The costs associated with downtime and repairs on sensitive electronics that fail due to heat or environmental contaminants, are an unnecessary burden. If you have any questions about how an EXAIR Cabinet Cooler can solve problems in your facility, contact an EXAIR Application Engineer.
Per the National Electrical Code (NEC) there are (3) classifications for areas that are defined as hazardous. They are Class I (gases & vapors), Class II (flammable dusts) & Class III (fibers), the focus of today’s Blog is on Class II locations.
Class II locations are those that are hazardous because of the presence of combustible dust. Note that the dust must be present in sufficient quantities for a fire or explosion hazard to exist. The fact that there is some combustible dust present does not mean a Class II hazardous location exists. Dust is defined as a combustible material that must exist as a finely divided solid of 420 microns (0.420 mm) or less. This will allow the dust to pass through a No. 40 sieve. Just as in Class I, Division 1 and 2, the subdivision of Class II into Divisions 1 and 2 identifies the likelihood that there is an explosion hazard.
Division 1 locations are defined as an area where the amount of combustible dust is either suspended in the air or accumulated on surfaces in a sufficient concentration to allow for ignition. The ignition could be caused by a failure or malfunction of the equipment in the classified area. Group E & F dust (see chart below) are considered conductive and could penetrate into electrical equipment such as electric motors, control panels, electrical panels, etc., and cause an electrical failure.
Group E dusts are metal dusts, such as aluminum and magnesium. In addition to being highly abrasive, and likely to cause overheating of motor bearings if it gets into them. Group E dusts are also electrically conductive and if they are allowed to enter an enclosure can cause an electrical failure.
Group F dusts are carbonaceous, the primary dust in this group is coal dust. Coal dust has a lower ignition temperatures than those in Group E. While Group F dust has a higher thermal insulating value than the layer of Group E. Therefore Group F requires more control of the temperature on the surfaces that the dust settles on. Group E dusts are semi-conductive, however if the voltages are 600 volts or less it is not generally considered a factor.
Group G dusts include plastic dusts, most chemical dusts and food-grain dusts. They are not electrically conductive. Generally these dusts have the highest thermal insulating characteristics and the lowest ignition temperatures. Therefore, the equipment used in Group G areas must have the lowest surface temperatures to prevent ignition of a layer.
Lastly, equipment rated for use in Classified Environments have a rating called the Temperature Code or “T-Code”. This is the temperature or temperature range that the rated device will operate normally and/or in a failed or failing state. Consider something as common as a light fixture, electric motors, etc., as they could become hot enough to cause ignition depending on the type of dust in the area. So be sure to check the “T-Codes” for every piece of equipment that will be used within a Classified Environment.
In 1815, Sir Humphrey Davy patented an oil lamp for use in coal mines, and coincidentally pioneered the movement to provide safe and reliable products for use in explosion-prone environments. In the days before electricity, miners used lamps that burned fuel oil for lighting. The problem with that was, deposits of underground coal are almost always accompanied by methane gas pockets which, when mixed with coal dust in proximity to an open flame, created terrible and deadly explosions. Davy’s design incorporated a brass net around the wick chamber that let the light out, and let oxygen (necessary for combustion of the fuel oil) in, but if methane entered the wick chamber, it’d extinguish the flame and prevent ignition of the gas outside the lamp.
Industrial growth and the proliferation of electricity that (literally) powered it introduced new hazards in a number of industries other than just mining…which grew exponentially through the 19th century, since coal was the main fuel in electric generating plants. As hazards were identified (usually, unfortunately, by a tragic accident), new and safer products were developed, and eventually, industry professionals implemented controls & standards to make sure these new and safer products were designed, manufactured, and used for the prevention of future tragic accidents.
In North America, the National Electrical Code’s (NEC) system of Classes and Divisions specifies requirements of electrical product testing & use to ensure safety in this regard. In 2014, the European Union created the ATEX Directive, which specifies similar (but not identical) requirements, also aimed at mitigating explosion risks in industrial environments. In 2019, EXAIR introduced our HazLoc Cabinet Cooler Systems, which comply with certain NEC requirements, and we just recently introduced ATEX Cabinet Cooler Systems to comply with that directive.
Both the HazLoc (left) and ATEX Cabinet Cooler Systems are available from stock in NEMA 4 and NEMA 4X ratings.
Like our HazLoc Cabinet Cooler Systems, their ATEX counterparts have been subject to stringent UL testing to ensure compliance with the ATEX Directive. They’re approved for use in areas defined by the Directive as:
Zone 2 (an atmosphere where a mixture of air and flammable substances in the form of gas, vapour or mist is not likely to occur in normal operation, but if it does occur, will persist for a short period only) and
Zone 22 (an atmosphere where a mixture of air and flammable substances in the form of powder or dust is not likely to occur in normal operation, but if it does occur, will persist for a short period only.)
This fall, EXAIR will celebrate 40 years of dedication to safety and efficiency in engineering & manufacturing compressed air products for a wide range of applications. If you’d like to find out how our Cabinet Cooler Systems – or any of our Intelligent Compressed Air Products – can increase safety and efficiency, and lower sound levels for your compressed air usage, give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
Have you ever walked through a production facility and actually looked at and in electrical cabinets? If you did, you would find very few that are identical and even ones that are similar sizes; the internals can be drastically different. When I was in the metal cutting industry customizing, installing, and servicing CNC machines, the same model machine may have different drives for an extra option and can easily add additional heat load to the panel. Bring this up because it’s time we talk about how the dimensions of a panel are not enough to select the level of cooling needed.
Some manufacturers of air movers and “traditional” enclosure cooling method devices will use merely the dimensions of a panel to estimate a heat load and then treat the panel for the worst case scenario. Sometimes it may even be a worst-case scenario for that size of panel. I’m here to tell you from experience that’s not always the best option. This is why we like to have additional information, an “inside man” on the panel, if you will. We want to know exactly what kind of air temperatures we are seeing so that we can use that information combined with some math to determine an acceptable heat load that needs to be dissipated.
The information permits us to size the Cabinet Cooler system for your exact panel; even if you have two that are the same size but one of them has some additional drives or circuits running through it, we can account for that. The reason it is essential to size each panel that has anything different in it is that all devices have some level of efficiency. So the power they consume isn’t 100% converted into their intended function. This results in some level of heat generation. That means different internal components, and different heat loads, easy as that.
This is one of the reasons we took so much care when designing and refining ourCabinet Cooler Calculator. Each variable will impact the heat load and model selection for the Cabinet Cooler System. Some major factors, such as solar heat load and cabinet color, are even accounted for when panels are located outside. We even account for existing fans that will need to be removed to seal the panel. This is because all of these factors directly affect the amount of cooling needed.
Suppose you are looking to cool down some electrical cabinets throughout your facility and want to fully understand what heat load you may need to dissipate and maintain a safe operating environment; check out our Cabinet Cooler Calculator, orcontact an Application Engineer today. In that case, we can size the system while we are talking on the phone with you.
