Wiring:  Live to Live, Neutral to Neutral

Most of the power cords are with two cores, one "Live" (+) and one "Neutral" (-). 

Sockets are also with 2 contacts, one "Live"(+) and one "Neutral"(-).

Be sure to connect Live core to Live contact, and Neutral core to Neutral contact. 

In case of installing a switch in the power cord, the on-off (cutting) should be at the Live core.

Power Cords:  Which core is Live and which is Neutral?

U/L Cords:  The core with markings is Live, and the other without marking is Neutral.

T-Mark cords:  The core with markings is Live, and the other without marking is Neutral.

European Cords: The brown core is Live and the blue one is Neutral.

Sockets:  Which contact is Live and which is Neutral?

Always remember that in a socket the center pin is Live and the wall pin is Neutral. 

If there are contact screws on the bottom of socket, the brass color screw is Live and the chrome one is Neutral.

Some U/L sockets are with wire terminals, of which the black wire is Live and the white one Neutral.