Electronic Enclosures Types and Terms

  • Computer enclosures are housings made specifically for computers. Computer enclosures are usually made of metal and are used to protect the inner electronics from dust and moisture damage.
  • Custom enclosures are made to the detailed specifications of the customer. The sizes can vary to enclose a range of equipment, from a fuse box to a number of electronic devices and cables housed in a separate room, referred to as network racks.
  • Double-shielded enclosures have an inner wall that is isolated from the outer wall with the exception of the region where the power-line filters and coaxial connectors penetrate. Double shielded enclosures can also be rooms.
  • Electronic cabinets are filters designed to protect electronic parts from damage caused by dirt, oil, dust and moisture. Electronic cabinets, used in virtually every industry, give electronic components a plane of operation that improves their efficiency.
  • EMI shielding (http://www.emi-shielding.net) involves using materials, such as filters, gaskets and coatings to block, absorb or redirect electromagnetic waves, in order to prevent electromagnetic interference (EMI) from harming sensitive equipment. These materials are attached to the metal surface of such enclosures.
  • Junction boxes are a type of enclosure used specifically for wiring and the connecting of wiring to a larger unit and are often constructed with metal material. Junction boxes must have a cover plate and should be easily accessible.
  • Metal boxes are metal enclosures that protect electronics.
  • Metal enclosures are typically made of either aluminum or sheet metal. Metal enclosures are being replaced by enclosures made of lighter, more durable composites.
  • NEMA enclosures are a specific type of electronic enclosure that is certified by the National Electronic Manufacturers Association (NEMA), which rates the enclosures bases on the type of application for which they are used. NEMA enclosures are typically made from carbon or stainless steel and can range in size from a pushbutton panel to a room-sized panel.
  • Plastic enclosures are plastic housings that protect electronics.
  • Pushbutton enclosures are either rectangular or wedge-shaped. Pushbutton enclosures have cutouts for surrounding and securing pushbuttons and can be mounted to a wall, pedestal or suspension system.
  • Terminal boxes are similar to junction boxes and are used for the housing and protection of a connection point between two different types of wire.

Attenuation - A reduction in signal strength. Attenuation can occur naturally during normal signal transmission, or it may be produced intentionally by inserting a device in the path of the signal to reduce signal strength.

Bounding Surface - The outer surface of the electrical enclosure.

Cabinet - Often used interchangeably with either enclosure or rack. It is a piece of equipment designed to house or enclose something, such as electrical or process equipment.

Cable Glands - Seals that prevent water, dust, etc. from entering the enclosure at the point at which the cable is brought through the enclosure wall. Often, cable glands are installed via a gland plate.

EMI (Electromagnet Interference) Emission - The unintentional or undesired exiting of potentially interfering electromagnetic energy from electrical/electronic sources.

Flame Retardancy - The ability of a material to resist burning, sparking, sputtering or dripping when brought into contact with a naked flame. Not all enclosures are flame retardant.

Gear Tray - Also called a "mounting plate" or "mounting pan," it is a shelf that allows the mounting of equipment inside the enclosure. Gear trays are typically located at the rear of the enclosure, though some may be movable.

Gland Plate - Removable section of the enclosure, usually located on the bottom. The gland plate can be removed to allow the easy fitting of cable glands.

Permeability - The extent to which a material can be magnetized.

Plinth - Term used to describe various styles of mounting bases for floor-mounted enclosures.

Shielded Cables - Cables that have shields, such as braids or foils, to prevent EMI from entering or exiting the cable.

Rated Current - The input current of the equipment as declared by the manufacturer.

Shielding Vents - Vents that are used for HVAC or simple ventilation of shielded products, such as cabinets, rooms or enclosures. Some shielding vents also provide high shielding or air filtering.

Shielded Windows - Shielding consisting of a thin conductive film on the glass or a fine-wire mesh or metalized open-mesh textile.

Shielding Gasket - A material that maintains shielding effectiveness across a seam or gap in an electronic enclosure.

Type 1 - A NEMA rating indicating that the enclosures are intended for indoor, non-hazardous locations. Type 1 enclosures are mainly used to provide protection against limited amounts of falling dirt.

Type 3R - A NEMA rating indicating that the enclosures are intended for use in outdoor, non-hazardous locations. Type 3R enclosures are mainly used to provide protection against falling rain and external ice formation.

Type 4 - A NEMA rating indicating that the enclosures are intended for indoor or outdoor use in non-hazardous locations. Type 4 enclosures are mainly used to provide protection against splashing or hose-directed water, damage from external ice formation and windblown dust or rain.

Type 12 - A NEMA rating indicating that the enclosures are intended for indoor use in non-hazardous locations. Type 12 enclosures are mainly used to provide protection against dripping, non-corrosive liquids, circulating dust and falling dirt.