Electrical enclosures are the boxes that protect electrical equipment from dust, water and heat. Some are fitted with an infrared window, so that an inspector can check for hot spots without opening the box.
An electrical panel holds the switches, wires and drives of a machine. Dust and water inside it cause faults. So the panel sits in an enclosure, usually made of steel or plastic. Its protection level is given as an IP rating, for example IP65. The first digit, 6, means that the box is dust-tight. The second digit, 5, means that it keeps out jets of water. A fan or an air conditioner may be fitted to take heat away.
Consider a control panel at a water pumping station in Guwahati, standing outdoors through the monsoon. Wind-driven rain hits the door for hours. A rubber seal around the door of an IP65 enclosure stops the water from entering, so the drives and the PLC inside stay dry. The sealed box also keeps out the dust and insects. A sealed box traps heat, so a small fan with a filter, controlled by a thermostat, is fitted to keep the inside from getting too hot.
The weakest points in a panel are the joints where wires are connected. A loose joint has more resistance, so it heats up. Left alone, it can start a fire. Heat is invisible, but a thermal imaging camera shows it as colour. An inspector should not open a live panel, because the risk of an electric arc is high. So some enclosures have an infrared window, a panel that infrared light can pass through, and the inspector points the camera through it.
The enclosure is also used outside factories. For instance, an EV charger keeps its electronics in an enclosure that must withstand rain and dust.
The wires that the enclosure protects are the connectors and cable assemblies. Server rooms use a related kind of box, the rack, to hold equipment.