What color is circuit number 23 in a 120 volt three phase panel?

Your service entrance cable could be Black, Red, White and bare cable. In a 240 V panel there would be 240V between Black and Red and 120 V between Black and White and Red and White. In the branch circuits the colors are Black, White and Bare wire. Black is Hot, White is Neutral and bare wire is earth ground and should be terminated on the ground bus in the main panel.