Article 200.10(A) in the 2020 NEC reads thus:
What does "connection to more than one side of the circuit" mean? I think that this expression occurs only here in the NEC.All devices, excluding panelboards, provided with terminals for the attachment of conductors and intended for connection to more than one side of the circuit shall have terminals properly marked for identification, unless the electrical connection of the terminal intended to be connected to the grounded conductor is clearly evident.