Plug and socket

The invention discloses a plug comprising a first contact pin, a second contact pin, a third contact pin and a first substrate, wherein the first contact pin, the second contact pin and the third contact pin are partially fixed in the first substrate; the first contact pin is connected with the N end of alternating current; the second contact pin is connected with the L end of the alternating current; and the third contact pin is connected with a sheltered ground. The invention also discloses a socket matching with the socket for use. Through the cooperation of the plug and the socket, a charging pile is ensured to be electrically connected with a battery or a battery controller so that the charging pile charges the battery.