To many end-users an enclosure is simply a box in which to store electrical components or connections, and the specification process needs to take no more time than is required to decide on the right size. However, if you look at the range of options on the market it becomes apparent that there are many more variables to take into consideration. Spelsberg alone has over 4,000 standard products and each one of them has been designed with a unique set of requirements in mind.

Enclosures are available in many different materials, shapes and sizes and all of them are relevant to different sectors of the market.

Enclosure material is the first, and probably most fundamental, choice to be made. The two basic choices are plastic vs. metal but in reality the two groups can be broken down further: eg. polycarbonate, ABS, polystyrene, glass reinforced polyester (GRP), aluminium, steel, and even cast iron.

For the majority of modern applications plastic construction is the favourable choice as it’s typically lighter, less expensive and easier to include built-in internal mounting options for quick installation. However metal enclosures are useful for applications which require protection from potentially heavy external knocks, such as building sites, mining and quarrying. Though in these instances GRP may be considered superior as metal enclosures are prone to corrosion once dented.

Despite the wide selection of choice between different plastics there are typically a few easy to follow rules. Polystyrene and ABS enclosures offer a lower tensile strength and less UV protection but the costs are low which make them ideal for applications which are inside and may require a lot of units at a lower cost. Polycarbonate offers increased tensile strength and is UV resistant which makes it ideal for harsh applications and outside installations.

Having chosen the correct material for your application it’s also important to consider the internal designs of the enclosure and how they meet with your requirements. The most obvious consideration is the size. Both the external and internal dimensions should be considered as some enclosures will make better use of the space inside for housing your component. Sourcing an enclosure with the correct dimensions can ultimately make installation easier and less time consuming while also ensuring that the external aesthetics are optimised.

Due to the variety of components which may be housed within an enclosure, most good manufacturers offer a plethora of different internal mounting options. When you’re specifying an enclosure you should consider what will be housed within it and ask what mounting options are available. Typical examples are PCB or terminal mountings, DIN Rails or separate compartments for housing batteries.

Some applications are even more specialised and many of the enclosures that Spelsberg and other manufacturers produce reflect this in their designs. The most obvious example is the AK range of distribution enclosures which are designed to house components such as Miniature Circuit Breakers (MCBs) on a DIN rail with a transparent window which can be easily opened for access to the components.

Other examples of application specific enclosures from Spelsberg include the IBT and IBTronic junction box range for pre-cast concrete construction; WKe range of fire resistance enclosures with up to E90 protection; and PV enclosures for photovoltaic installations.

Good enclosure suppliers will employ sales engineers who have experience in the industry and are able to offer specification guidance based on your udesign. However, by understanding the basic requirements of your application you can ensure that the enclosure you choose offers all the protection and performance that will be required.

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