We are offering this package for use as hook up wire for the inside of DIY control panels. This variety pack contains 36" of each of the following:

10 AWG Black - For Hot L1 High Current from source input all the way through to the element output.
10 AWG Red - For Hot L2 High Current from source input all the way through to the element output.
10 AWG Green - For Earth Ground from source input to enclosure ground and element output.

16 AWG Black - For low current between Hot L1 to PID, Pump switches, Pump outlets, etc.
16 AWG Red - For low current between Hot L2 to PID, Pump switches, Pump outlets, etc.
16 AWG White - For low current between Neutral to Pump outlets, 120v contactor coils, etc.
16 AWG Green - For input earth ground to low current device grounds; SSR mounting screw.

12" Each of the following:
20 AWG Blue - For PID to SSR control DC signal, + polarity
20 AWG White w/Blue Stripe -For PID to SSR control DC signal, negative polarity

MTW/TEW stranded hookup wires.

You really don't want to try wiring your panel with a single color as it makes troubleshooting nearly impossible.
10AWG is usable up to 30 amps
16AWG is usable up to 20 amps when loose inside a box.