What does each wire in a plug do?
The green (or green with yellow strips) is for Earth. This is
the D shaped socket in a US outlet. The Black (US) or Brown (UK) is
for Live. This is the narrow rectangular socket on a US outlet. The
White (US) or Blue (UK) is for Neutral. This is the wide
rectangular outlet on a US socket. The color code may vary for
other countries, so be sure to check.