[LazyPup]

Most fixtures would have color coded wires with the black being the powered conductor, White is circuit common, and bare or green for grounding.

From you description it sounds like you have a hanging fixture that is wired with "Zip cord".

Zip cord is the molded two wire cord that we commonly associate with lamp cords or light duty extension cords. The wire is called zip cord because it can be cut at any point and the two wires separated like opening a zipper to make working leads to complete the wiring.

If you will examine the cord very carefully you will note that one of the two wires has a smooth covering while the other one has very small molded ribs running the full length of the wire. (Rub your finger nail across the wire and you can feel the ribs.)

The wire with the ribs is the "identified conductor" and it is supposed to be used as the circuit common or neutral, which is to be connected to the white wire from the source.

The wire with the smooth covering is the "non-identified conductor" and it is to be used as the circuit "power or line", and which is to be connected to the Black wire at the source.

When wiring a lamp socket the ribbed or "Identified conductor" is to be connected to the "Shell" The shell is the outer part of the lamp socket that has the screw threads to hold the light bulb.

The smooth wire (Non-identified conductor) is to be wired to the center contact of the light socket.

If you will examine a common lamp plug you will see that one of the two plug in tabs is wider than the other. The widest tab is the identified conductor and the ribbed wire should be attached to the wide tab.

Although a lamp will work with the wires connected either way, the intent here is to insure that only the center contact of the lamp holder is powered and the shell or outside part of the lamp holder is neutral.

If you happen to reverse the wires, the exterior part of the lampholder is powered and there is a potential that if someone were to touch it while touching another grounded surface they would get shocked.