Standards
UL 508A
Definition
The United States safety standard for the construction of industrial control panels, covering component selection, spacing, conductor sizing, marking, and enclosure suitability.
It says nothing about whether the control scheme is correct. A panel can be flawlessly listed and still start the wrong pump.
The label is applied by a shop holding the listing, so a field modification made outside that program can invalidate it.
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See also
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