Understanding electrical boxes and enclosures

October 17, 2014

Electrical boxes and enclosures come in different sizes and configurations, which means users must take the time to become familiar with them before making a selection.

Understanding electrical boxes and enclosures

Many technical factors determine the ideal box for a given application.

  • You'll need to think about functional aspects like internal temperature control, material properties and shielding.
  • A well-chosen box provides a safe and reliable housing for mount switches, knobs and displays. It doesn't have to be all function, though.

There are many options that are just as pleasing to the eye as they are functional. However, the design and construction must adhere to strict guidelines to ensure safety.

Structural configurations

Electrical enclosures are made from different types of materials, which influence their structural properties and range of suitable applications.

  • These materials include processed wood, plastic, fibreglass, stainless steel, aluminum, natural wood and carbon steel.
  • Manufacturers employ several fabrication methods for metals, such as cold rolling, galvanizing and hot rolling.

Punched openings or knockouts enable easy fitting of conduits, connectors and cables. The application environment has a bearing on the choice of material. In addition, the physical properties of the material must create a robust structure. The presence of corrosive agents compels you to make use of materials that perform well in certain environments. For example, aluminum resists corrosion by forming a layer of oxide.

Enclosure selection considerations

You need to consider the intended applications for the box ahead of environmental and material considerations.

  • You should look into issues such as mounting and the need for a disconnect.
  • In addition, you should take into account several factors when selecting the appropriate size of box. These include service connections, climate control configurations, internal components dimensions, economics and aesthetics.

It is vital to pick a box with an ideal rating for the target environment and application.

  • Proper evaluation of thermal management considerations helps you improve the durability and performance of electrical components.
  • Environments with high temperatures require sufficient heat dissipation mechanisms.
  • On the other hand, colder temperatures call for heat generation capacity.
  • In some cases, security is a key aspect that demands physical features capable of preventing unauthorized or accidental operation. Hinges, locks, latches and hardened structural properties play a crucial role in this regard.

Additional considerations include enclosure weight load capacity, sunlight or UV resistance, flammability and impact resistance.

  • You must bear in mind that weight load capacity determines the right amount of maximum weight for a given enclosure size.
  • Exterior surface roughening normally caused by UV exposure should not affect internal components, but it dictates the choice of material.

*Not only is it dangerous, it may even be illegal in some provinces, such as Québec, to do your own electrical wiring. The solution: consider hiring a master electrician.

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