Industrial Enclosure Selection Guide
Enclosure Selection Guide
An electrical enclosure is a cabinet typically used for housing electrical or electronic equipment; to mount things like knobs, switches and displays. It also used to prevent electrical shock to users and equipment along with protect the contents from the environment. The enclosure is the part of the equipment which is seen by users. It is usually designed not only for its utilitarian requirements, but also to be pleasing to the eye with easy access. The housed electronics may place many demands on an enclosure for things like heat dissipation, electrostatic discharge, radio interference along.
There are a lot of factors to consider when selecting an enclosure. The following is a list of key factors and guidelines to help make your selection.
1- Size- The obvious first criteria for selecting your enclosure is the size including height, width, and depth. When analyzing the location, you need to consider the door opening for access and maintenance. Inside the enclosure you will need to note that most backplates that are used for mounting the equipment sit about 1” off the back of the enclosure. For the depth, you need to allow the additional 1” to the height of your components that will be installed in the enclosure. This will ensure that all will fit while still allowing the door to close properly. Also, the mounting backplates are typically 2” smaller in width and height than the enclosure size. That is to allow space a 1” spacing around the outside of the backplate for installing the backplate once the enclosure is mounted. You need to take into consideration how many components you must put inside the enclosure and have proper spacing for things like heat dissipation, wiring and ease of access.
2- Environment- All enclosures have ratings, called NEMA ratings that defines the types of environments the enclosure can be used for. The ratings define indoor or outdoor use along with conditions such as dirt and dust conditions along with water and liquids. This will ensure the components inside the enclosure will be properly protected. See our NEMA guide or NEMA chart which both show the NEMA ratings and conditions for which they are protected. You will also want to consider what material the enclosures are made from. For example, stainless steel and non-metallic enclosures have a NEMA 4x rating for use in corrosive environments. Steel and Stainless Steel are heavier but very durable. Some Non-metallic enclosures break down with the UV rays or become very unsightly. See our chart for the advantages and disadvantages of each enclosure material type.
3- Modifications- Many times you will need to make modifications like holes or cutouts for things like access or mounting. Once again, the type of material the enclosure is made from can make the job tougher or easier. For example, Stainless Steel is very difficult to drill or cut into. Metal is still a little difficult but much easier than stainless steel. With Non-metallic enclosure fiberglass is easier than the metals but more difficult than other thermoplastics because the glass is highly abrasive which dulls your cutting tools. The other thermoplastic enclosures like polyester and ABS are very easy to modify.
4- Thermal Issues- Evaluate environment of the location the enclosure will be used. The outside and inside temperature must be evaluated. Excess heat or cold can seriously affect the performance or damage any electronic components housed inside an enclosure. Recognize the exposure to the ambient heat, internal heat, and solar gain from the sun exposure. For example, an enclosure located with full sun exposure and no watts of internal heat load can reach temperatures in excess of 160°F degrees.
Non-metallic enclosures are made of thermoplastics which are superior insulators but at the same time poor at dissipation of heat or cold. Metallic enclosures are poor insulators and good conductors. This will affect the thermal conditions for the enclosed components. Insulators like non-metallic enclosures can keep the heat or cold out, but at the same time don’t dissipate heat generated by the electrical components inside. They may need ventilation to dissipate the excess heat. Conductors like metallic enclosures are poor insulators. They don’t insulate but instead absorb the exterior cold or heat, but at the same time can dissipate the heat created from the electrical components inside. Proper placement in shaded areas can work to the advantage for enclosures or sun shielding can help. You need to evaluate which type of enclosure would work best based on the interior heat load and the exterior temperature. In many cases you may need to add vents, fans, air conditioning, or heaters to keep the components at the proper temperature.
(Also note that typically enclosure coatings, gaskets, windows and plastics are designed to withstand tests of -22°F for a period of 24 hours and up to 140°F for a period of 168 hours.)
5- Aesthetics- The appearance of the enclosure is another consideration. Stainless Steel is a high quality nice finish, but the cost is higher. Aluminum is another nice finish enclosure but may be less durable. Painted steel is not quite as nice as other metals but is more cost effective while being very durable. Non-metallic thermoplastic enclosures don’t always look as nice or durable as the metal enclosures but are less expensive.
6- Price- The price of enclosures can vary by a great deal based on the construction and materials. Like with anything else you need to weigh the trade-offs between the price and things like, durability, aesthetics, thermal properties, ability to modify and more. Typically, the order of price from higher to lower is Stainless Steel, Aluminum, Painted Steel, and Non-metallic. See our chart below to see the comparisons.
7- Weight- At time weight can be an issue for circumstances like mounting conditions or materials, ease of access for installing and more. From the more heavy to light we have Stainless Steel, Painted Steel, Aluminum, and Non-metallic.
8- Durability- This can be an issue in a highly active environment where there is moving equipment or personnel. Some enclosures are more durable from impact than others.
9- Hinges- There are enclosures with no hinges and just a screw cover for those cases where the components inside will rarely need to be accessed. Standard hinges are typically used where the door can easily and quickly be opened and shut, especially where access is often needed. Continuous hinge enclosures are often used in cases where things need to be mounted to the door, like pushbuttons, indication light, HMI screens and more.
10- Latches & Locks- The latch type will be a factor in the access and security you need to have. Quarter-turn latches are easy to open and close along with some clamp type latches but they are not a convenient as a handle with a three-point latch system. Also, there are handles with keylocks, quarter-turn latches with special bits to open, and there are padlock latches included or can be added to an enclosure.