The National Electric Code defines industrial electrical control panels as an enclosure or open panel containing two or more power circuit components, control circuit components, or a combination of the two. Panels may include:– Auxiliary devices
– Disconnect means
– Motor branch-circuit protective devices
– Motor controllers
And other control devices.
Under NEC guidelines, industrial electrical control panels operate on less than 600V. Panels provide the signals needed to control equipment but contain neither the main power source nor the equipment itself. Industrial control panels send signals to a wide range of industrial equipment, including but not limited to:– Heaters
– Industrial machinery
– Pump loads
– Refrigeration equipment.
Types of Industrial Control Panels
Industrial control panels come in two basic forms: enclosed and open. Enclosed industrial control panels include the enclosure itself, all components within the enclosure, and all components mounted to the enclosure walls or cover.
Open industrial control panels include internal wiring, field wiring terminals, and components mounted on a sub panel, but have no enclosure.
What Standards Apply to Control Panels?
In addition to NEC 409.2, several other standards apply to industrial control panels. These include UL 508A (Standard for Industrial Control Panels) and NFPA 70 (Electrical Standard for Industrial Machinery. In addition, the design, installation, testing, and maintenance of control panels is subject to standards set out by IEEE, NECA, and NETA.
Industrial Control Panel Maintenance
– Control panel maintenance is made easier by good design, with all wiring, terminals, and components clearly labeled. Regular maintenance includes:– Connection controls: tightening connection screws can actually worsen connections. Instead, use an infrared gun to test for high resistance; disassemble, clean, and reassemble terminals as needed.
– Dust Control: while cabinet floors can be vacuumed, remember the enclosure is energized, so follow standard safety precautions before cleaning. Do not vacuum close to circuit boards without first following electrostatic discharge procedures.
Insulation: periodically perform insulation resistance tests to identify potential wiring failures.
– Pest control: depending on your environment, this may include roach bait or rodent traps, which must be periodically checked and replaced.