2.2.7 Electrical cabinets

Electrical or industrial control panels, electrical cabinets, electrical enclosures or e-racks are boxes where electrical components are stored. These components perform different tasks for monitoring and controlling a machine or a production process.

As mentioned in the introduction of Operational Technology (OT), reliability & safety, maintainability & standards, and certifications are of high importance in the OT sphere. Therefore, the different electrical devices that supervise and control the machine must fulfill these requirements.

What is an electrical cabinet?

A box that stores all the electrical components which automate a machine or a production process.

List of components

The list of components of an electrical cabinet can be distinguished in two types, non-electrical or mechanical components and electrical components.

Non-electrical components

  • Back panel: steel sheet where components are attached
  • DIN rail: steel rail with standard width for mounting devices. DIN refers to the German Institute for Standardization
  • Wiring duct: helps to route and organize cables and wires that power and connect the electrical devices

Electrical components

  • Main circuit breaker: switch where power comes in and energizes all the electrical devices
  • Surge suppressors: protect all electrical devices from over voltage
  • AC power distribution: composed by several circuit breakers, serves as a node that enables the connection for other devices which needs AC voltage
  • Power supply: change AC voltage to DC voltage. Common voltages are 5V, 12V, 24V DC
  • DC power distribution: circuit breakers but for DC voltage
  • Terminal blocks: nodes that serve to connect two wire together
  • Ethernet switch: allow elements in the panel to communicate between each other
  • PLC: send and receive data from instruments wired in the machine
  • Terminal blocks: connection points which field instruments such as sensors or actuators are wired into the electrical cabinet. Can be digital or analog type
  • Relays: PLC from overcurrent while enables digital outputs

Documentation

A very important part of an electrical cabinet is the documentation with mechanical, electrical and network diagrams. Moreover, list of materials, consumables and spare parts should be added. There are several standards of how to do this documentation, which will be shared in the following subchapter relating it to certifications. Most relevant is that the cables and elements must be identified, so any authorized technician can troubleshoot and give maintenance to the e-rack.

Last modified October 5, 2022: Historian article (#107) (5f30dc0)