While the electrical and electronic equipment required for control panel assembly is the focus of your design work, underestimating or delaying the selection of an appropriate enclosure can lead to major problems that can be avoided with just a little forethought. Save yourself the headache by considering these key factors in advance. Which electrical enclosure should use?
A quick Google search for "electrical enclosures" yields 58 million results, so it's no surprise that some specifiers may feel a little overwhelmed by the task. For most applications, there is a perfectly acceptable solution - in fact. It is ideal to seek support from your enclosure supplier when required, but you need to know some key information to decide what is appropriate. There are many factors that can influence the selection of an enclosure for a particular application. We will focus on seven common considerations for electrical enclosures.
1. level of protection
2. Certification and approvals
3. size
4. access requirements
5. Cost
6. temperature environment
7. Corrosion resistance.
Level of protection
The protection class of an enclosure indicates how well the enclosure protects the equipment inside. Enclosures are rated according to their ability to prevent the ingress of various levels of dust and liquids. These protection ratings are often referred to as "type" or "NEMA" (National Electrical Manufacturers Association) ratings.
Certification and approval
Standards organisations have created rating measurements for the performance of different products. Categories of electrical enclosures are defined by organisations such as NEMA, CSA, UL and IEC to determine the ability of the enclosure to provide protection against dust, dripping water, hose-shot water, etc.
While all of these standards are designed to guide users in making the right product choice, there are some important differences between them.
In North America, NEMA, UL and CSA are the most commonly recognised standards organisations. They are virtually identical in their ratings and testing of enclosures.
UL and CSA require enclosures to be tested in approved laboratories to prove their performance. They regularly inspect manufacturers to ensure they are using approved materials and constructing products according to previously tested product designs. In turn, they provide a "certification label" that is permanently affixed to the inside of the enclosure.
While NEMA ratings are a common reference, unlike UL/CSA, this organisation does not provide testing services, they leave compliance and testing to the manufacturer's discretion and they do not provide a 'certification label' for enclosures.
In Europe, the IEC rating is the most commonly recognised standard for enclosures. the IEC rating is similar to NEMA but with different requirements for passing or failing. the IEC is primarily concerned with entrance protection and does not include unique ratings for enclosures in corrosive, rusty, oil, ice or explosive (hazardous) environmental conditions.
Dimensions
This is basic, but consider the minimum size of the enclosure required to accommodate all the installed components - for example, how deep is the deepest component? Then, confirm whether there are physical size constraints where the enclosure is to be installed - is the available space wide, short and wide, tall and thin, etc.
