On a 3 wire plug (NEMA 5 configuration, 125v 2 pole 3 wire grounding) the narrow blade is the "hot" lead, the wide blade is the neutral lead, and the U shaped prong is the equipment grounding conductor (EGC). Most 2+G non-metallic-cables (NMC) are color coded for Black = "hot", White = neutral, and Bare = EGC
The hot(black)) wire on a lamp cord will be the the side that has the more narrow prong on the plug-in. The Neutral (white) wire goes on the wide blade,
If there is no ground wire connect the ground wire to the neutral wire.
A NEMA 5-20 plug is a standard 3 prong plug. It wires the same as a NEMA 5-15 plug (Ground wire to the "D" contact, Hot to vertical terminal and neutral to the horizontal terminal (with the Ground terminal either at the top or bottom)).A 5-20P plug has the neutral blade rotated 90°. The 5-20R receptacle usually has a T-shaped neutral hole, to accept both 5-15P and 5-20P plugs.
The best way to find the neutral wire on any lamp is to ring the wire out. Before there were polarized plugs and receptacles a lamp could be plugged in either way. All new lamps have polarized plugs where the neutral is connected to the shell of the lamp holder and the "hot" wire is connected to the center pin deep in the lamp socket. Back to your goose neck lamp, you will need a meter that reads resistance and use it as a continuity meter. With the lamp unplugged and the lamp's switch in the off position connect one lead of the meter to the shell of the lamp holder. Take the other lead and touch it to one of the plug cap blades. If the meter gives a reading it is that blade that is the neutral wire. If there is no reading then that blade is considered the "hot" wire. If you are changing the plug (cap) out for a new one connect the newly established neutral wire to the silver coloured screw and the newly established "hot" wire to the gold coloured screw. Now when ever and where ever the lamp is plugged into a voltage source the polarity will be correct and the lamp will be much safer to use.
a loose connection of a neutral wire
The neutral wire and power wire are never connected together.
Look at plug, wider blade is the Neutral (MARK IT) the more narrow blade is Hot (MARK IT) Cut end off wire.. Inside a wire splice box wire nut black to hot, white to neutral. This is a very basic task however if you have no experience maybe contact an electrician.
On a lamp cord or two wire extension cord the writing is on the neutral side. Double check this by tracing the wire down to the cord end. You should find the neutral wire connected to the wider blade, of the two blades, of the plug cap
On a molded 2- or 3-wire line cord the ribbed conductor is the neutral conductor. On a polarized 2-prong plug it will be connected to the wider blade. On some line cords the neutral conductor may have a white stripe instead of ribs.
An L5-30P is a two pole three wire grounding 30 amp, 125 volt plug . The neutral wire is connected to the W terminal, the ground wire to the G terminal and the hot wire to the only terminal that is left. The small blade/slot is neutral (white), the larger blade/slot is hot (black) and the notched blade/slot is ground (green).
An extension cord that you plug into your house is neither positive OR negative. It uses alternating current so there's a live wire and a ground. Only direct currents (like those in cars) have positive and negative. On a two wire extension cord the ribbed side is the neutral. If you look close and it is a moulded plug on the end of the extension cord you will find that the side with the rib is also the same side as the wider blade on the plug. This corresponds to the wide blade hole in the receptacle which is also the neutral side of the receptacle.
What you are refering to is a polarized plug. The wide connector forces the proper orientation in the outlet. This is so that the hot and neutral connectors in the plug, match the hot and neutral (cold) prongs on the plug. This forces a switch to operate on the "live" or hot wire. If a switch interrupted the flow of electricity in the neutral wire, the appliance would still shut off but the plug itself will remain "hot" whcih is a shock hazard. No, the wide blade on a plug is the neutral connection.
In the UK the neutral wire is 'blue'.
The identified conductor on a two wire lamp cord cable will be the neutral wire. The identification will be a raised rib or on some the wire identification data will be used to identify the neutral. This wire connects to the wide blade, using a silver coloured screw on the plug (cap) as a connection point.
neutral
In North America the connections for a 15 amp cap (plug) goes as follows. 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.
If there is no ground wire connect the ground wire to the neutral wire.
white. Screws on that side (neutral) should be silver. "Brass" side gets the Black (hot) wire.