Lets be clear about the purpose of the neutral lead -- it returns unbalanced currents to the breaker box instead of sending them through the chassis, water pipes, etc. A proper 3-wire configuration will not have unbalanced currents, but a 4-wire could have unbalanced currents (e.g., using 120V for electronics). So, if the unit is designed to be hooked up either 3-wire or 4-wire, then use whichever connection fits your wall receptacle. In the case of 3-wire, do not attach the neutral terminal in the unit to ground, let it float unless otherwise directed by the manufacturer. In case of 4-wire, bring the unit neutral to the receptacle neutral, and don't attach it to any ground terminals. kas

The third prong is connected to a bare copper wire that is grounded at the service panel. It is for the purpose of grounding certain kinds of electrical appliances to prevent fires and shocks and to prevent minor shorts in outlet boxes from starting fires (it also grounds metal outlet boxes). Double insulated appliances and table lamps do not have a third prong. A ground fault outlet is similar but is more sensitive and trips more quickly at the receptacle or the panel in areas where you are likely to inadvertently ground yourself like near plumbing fixtures while using an appliance. To add a third prong you will need to replace the wiring unless the existing wiring, for some reason, has a grounding wire or grounding strip that was not used. The first step is to ask an electrician to look at it and give you a price rather than guessing.

A polarized plug is primarily for devices that have some exposed metal attached to one side of the AC line. The common one is a lamp where the threaded side of the bulb (as opposed the the button in the middle) may be exposed. This makes sure only the grounded conductor is connected to that side. Plug is the thing with the prongs. The thing on tend end of a extension cord is a socket. The thing on the wall that you plug it into is a receptacle. Obviously you can always use a three wire extension cord with a two wire device just as you can plug a two wire cord into a three wire (Grounded) receptacle. There are two things that determine wire sizing in this situation. First is how much does the device draw. A two pin plug isn't going to draw more than 15A and usually much less. In that case a 14g cord is fine. The other is how much voltage drop is there over the length of the cord. Again with the small loads I doubt you'll ave a problem. If you were trying to run a refrigerator or a table saw or something at the end, that might have sen an issue. Out door cords usually aren't worth repairing. You lose the water resistance with your repairs.

I stand by my statement. You might read the current information etc. You are correct they are bonded together at only one place in an instillation; some locations now require that they are not. You are also required to have separate bars for the neutral and safety ground, if they are the same why? Why do they only want a single point ground? The earth is the ground and the reference point and hence the term ground. Why do you think the 25 ohm or less ground rod resistance to earth requirement exists? I know of farmers that ran a single wire to an outbuilding and drove a ground rod for the other to save money and the lights worked just fine. Your assumption of a ground fault does not compute. You describe a phase to neutral fault not a ground fault. Remove the bonding screw and connect a breaker to the safety ground then you have a ground fault and if the system is correct the breaker will trip. To make it easy just connect a test light between them, if it does not light you have a problem. Whenever a current flows through a conductor there is a voltage drop, ohms law defines this. You do not want that drop in the ground circuit. The difference can do interesting things if you get between them. Do you want to sit on the ground and when you turn on the power tool gives you a zap? The neutral carries only the difference current between the phases, the ground caries none. I assume you have four wires in your box, two phases (black and/or red), one neutral (white or bare) and one ground (green or bare separate from the neutral). All branch panels are connected with four wires, 220 assumed, one neutral, two phases and one ground. The normal transformer that feeds a house has a center taped winding with the center tap connected to the ground and called the neutral. If the neutral fails the safety ground will carry the current and protect your system that is why they upped the wire size requirement for the ground many years ago. Then you could get 12X2 with a smaller gauge ground #16 I think). The Edison transformer is also grounded via a ground rod on both the primary and secondary sides. I know this first hand, I have a neighbor with an open neutral and his ground current is coming in my city water pipe as well as the neighbors. I see 10 Â 30 amps on the water and gas pipes, even with my Edison power disconnected. Edison says this is normal and cannot do anything about it. They also told me it is very common in older subs and was caused by open neutrals.. The equation is resolved with the addition of a CFGI breaker, if the neutral opens it will trip if there is any connection to the earth. AFCIs take care of the arcing fault problems. CH makes a combo that costs about the same as the AFCI. I have a transfer panel out side and that is where they are bonded together as code requires. Four conductors connect each panel and sub panel. There is no bonding screw in any of the panels inside. The inspector did check this. You are correct in the normal flow of current. GFCI breakers measure the current in both wires, if they are more then about five mA different it trips. Where do you suppose the current is flowing?