Which flexible wiring method is permitted between a time clock and a panel?

The correct choice regarding the permitted flexible wiring method between a time clock and a panel is to use 1/2" LFNC. LFNC, or Liquid-tight Flexible Nonmetallic Conduit, is specifically designed for use in applications requiring flexibility and protection from moisture and corrosion. It is compliant with the National Electrical Code (NEC) for certain installations, making it suitable for connecting a time clock to a panel, where movement or vibrations may occur.

The use of LFNC is advantageous in scenarios involving installations where environmental factors might necessitate this type of conduit. It provides necessary protection while ensuring that the installation remains flexible and adaptable. Other types of flexible conduits listed in the options may have different applications or limitations under the NEC concerning areas such as outdoor installations, exposure to chemicals, or specific mechanical protection requirements, which makes LFNC the most appropriate choice here.