Steel Enclosures & Junction Boxes
Electrical enclosures are designed to house industrial components and to protect them from the surrounding environment. They are also designed to protect operators from electric shock. They come in many different shapes, sizes and materials. Some things to consider when selecting the proper enclosure would be the number of components housed inside and what material and rating will provide the appropriate protection.
The National Electrical Manufacturers Association (NEMA) has devised a rating system to set performance standards for electrical enclosures. Manufactures follow these universal standards when making their electrical enclosures and label them accordingly. The most popular NEMA ratings are listed below.
NEMA 1 provides the least amount of protection and is for indoor commercial applications.
NEMA 3R provides protection against snow, rain and windblown particles. These enclosures can be indoor or outdoor and are commonly used for utility boxes and meter cabinets.
NEMA 4 provides protection against all weather conditions as well as being watertight. These enclosures are commonly used to house hydraulic controls, wiring and operator consoles.
NEMA 4X provides the same protections as NEMA 4 with additional corrosion protection. These enclosures are commonly found in water treatment facilities, marine environments, oil and gas industries and industrial food processing.
NEMA 12 provides a dust-tight enclosure, but are not watertight and should not be used in wash down environments.
Steel enclosures are made with carbon or mild steel for indoor and outdoor enclosures. Carbon steel is a strong and cost-effective material however, it is susceptible to corrosion from exposure to moisture and oxygen. Carbon steel enclosures require a powder coating or paint to provide protection from the elements.
Junction boxes are enclosures that house wire connectors or terminal blocks and are designed to protect the devices from harsh environmental conditions as well as operators from electric shock. They can distribute power from one location to many other locations or they can collect control signals from I/O devices and bring them back to a central control panel or cabinet.
