Boxes, enclosures, and racks are mechanical elements of a system that provide for structure and encasement of electronics products. There are a massive variety of options available off-the-shelf for these devices, but in many instances (especially in the case of boxes and enclosures) they must be custom designed for a particular product.

Boxes are available in a number of options. There are standard electronic boards that can be used to implement products (for example 'Arduino' and 'raspberry pi') and boxes are available to house them with mounts for the boards and physical ports for connectors. There are boxes for housing electronic 'breakers' and 'fuses' called 'breaker boxes.' Such boards and other control boards can be housed in off the self-cabinets. Junction boxes store electrical cable connects to insulate for safety and weather proof.  Enclosures, like cabinets, can have security locks and be able to be mounted on walls. They house electronic circuit boards and in the case of the power supply for business and homes, may also house power meters.

Racks slot in modules as a convenient way of vertical stacking or horizontally holding multiple modules in the same place. Rack systems will typically have rear or front entry for modules that may have cabling to other modules and in or out from the system or there may be a 'back-plane' which is a large PCB with connectors that enable modules to be plugged in and out of the rack. Racks can have provision for doors and can be sealed. In the case of high-power systems or systems in dangerous environments, the rack enclosure may have flame channels to guide fire, smoke or explosion. There are standard rack sizes available.

Card racks are similar to racks of modules. They typically have backplanes and are designed for special characteristics like high-speed communication between cards, provision for redundancy on power supplies, and cooling.  They support standard card sizes (for example VME, cPCI), and racks are defined by the number of cards they support (6U, 9U).