Which wire is the ground on a lamp cord?

Answer 1

For a flexible lamp cord:

If it is in the US, Canada or other countries using the similar wiring codes, if the insulation on the wires is colored then White is intended for the "Neutral", Black for the "Hot" or "Live" and - if there is one in the cord - Green should be used only for the protective safety "Ground" wire.

On lamp cords which are fitted with only a 2-prong plug, it does actually matter which way round the hot and neutral are connected. Except for very old style appliances or lamps because the plug can be inserted into a socket outlet only one way on modern devices.

One kind of plug which has 3 prongs - for separate hot, neutral and ground wires - can be inserted in only one position to ensure that correct connections are made for each of those wires. Another kind is a polarized plug where one prong, the neutral prong, is wider than the hot prong.

If the lamp cord is clear or a solid color, and has only 2 wires, one side may have a raised ridge and the other side will be smooth. The ridged side is intended to be used for the Neutral and the smooth side for the Hot. The National Electrical Code requires the neutral wire be identified.

Only do this if the device you are testing is unplugged: take a multi-meter, set it on ohms and check for continuity between the ridged wire (or wider prong) and the outermost metal part inside of the light socket, to confirm the lamp is wired correctly if it is you will get a reading close to or zero ohms.

The reason for this is if one accidentally touches the metal shell of a light bulb while unscrewing it, he or she will not be in contact with a hot wire and not get a shock. The hot wire is the switched wire and always the center contact in screw in light socket.

Note re. lighting cords in the United States: most of UL-approved 2-prong power cords have a polarized plug. The bigger prong is for the Neutral and the other prong is for the Hot.

If it is in a country in Europe or other places around the world using similar wiring codes, the Neutral wire is colored Blue, the "Hot" or "Live" wire is Brown and the Ground wire, if there is one in the cord, is colored Yellow and green.

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Old style lamp cords do not have a ground wire in the two wire set. It just has a hot and neutral wire. The neutral conductor has a raised rib for identification.

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As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,

on electrical circuits, equipment or appliances,

always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.

Answer 2

Answer for USA, Canada and countries running a 60 Hz supply service.

If you are constructing an extension cord make sure that the ends go on the right end of the cable. Match the wire end when looking at it, to the proper pin configuration of the plug. Looking at the plug from the blade side directly on you should see a larger blade (silver) on the right, smaller (brass) blade on the left and a U shaped ground blade on the bottom. The white wire connects under the right (silver) coloured screw, the black wire connects under the left (brass) coloured screw and the green wire under the green ground screw. Looking at the end of the cable it should be matched to this configuration. If it doesn't, look at the other end of the cable. No wires should cross when connecting to the blades on the plug, if they do you have the wrong end of the cable.

<><><>

As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.

Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.

Answer 3

The wire that connects to the outer, screw section of the socket is the neutral in a two wire lamp cord. This neutral wire also connects to the larger of the two blades in a polarized plug -- if one is used.

The smooth wire connects to the black hot wire and the wire with ridges connects to the white neutral wire.

Answer 4

Ballasts do not have a ground wire. The incoming ground wire should be attached to the grounding screw in the fixture or underneath the mounting screw of the ballast.