Saad,
I suspect you as asked about connecting the safety ground to the neutral because there's no green wire in your outlet. Like the other guys in this string said, if you connect the neutral to where the green was connected, it'll be tricky making sure you don't get a shock from the case, for example, if somebody wired the outlet wrong years ago. It'd probably be easier to just cut off the third prong on your power cord or don't connect the green-wire circuit to anything. That's the way it was years ago when I started in electricity. They also sell 3-to-2 prong converters that you could use to adapt your computer power to your 2-prong outlet.
I had an experience one time with these 3-wire plugs on the water heater for my horses. In the winter I have to put a heater into the horse tank, otherwise, the water will freeze and my horses would be VERY unhappy. This one winter, I'd just bought "Fussin' Miz" a high-strung TB mare. She shared the water tank with "Spalding", a dutch warmblood gelding.
The day after I'd put in the heater, Miz was really "fussin". She was upset about the water; she wouldn't drink and kept running around the pen. While I was watching, Spalding (just like he was going to explain the situation to me) walk to the water tank, lowered his head as if to drink, but hesitated. Then raised his head a little, then plunged his nose into the water and began to drink. If the tank were slightly electrified, I could imagine that he'd be shocked only at the instant his muzzle touched the water; once submerged, the current density through his muzzle, body, etc. would be greatly reduced.
So, I got a meter (back then it was a D'Arsonval-type). With one probe in the mud, one in the water I got a slight deflection on the most sensitive ac scale. That would be some micro-amps, which I suspect my very sensitive TB mare could feel.
So, I took out the heater, and she drank--lots.
The sheath of the heater (in contact with the water) is connected to the green wire. Neither the neutral nor the black wire are connected to the sheath, of course. (They are connected to resistance element.) In the electrical service to the barn, the green wire was connected to the neutral. I figure there must be some small amount of current passing through the soil at the club where the horses live. I believe overhead distribution lines can induce some current. Also, the poles that hold up the wires all have ground wires. These are connected to the neutral up on top of the pole, and to a ground rod at the base of the pole.
In the winter, when lots of tank heaters are operating for the horses, there could be 30-40 amps in the overhead wires. Over a stretch of 5-600 feet, an IR drop of several volts could be developed.
E=IR
where: E = 1-10 volts
I = 30 - 40 amps
R = wire resistance (approx. 0.3 milli-ohms per ft.)
This value of E, I'd expect, would be the Thévenin source term.
I didn't feel any shock when I put my hand in the water, but the skin on a person's hand is a lot tougher that a horse's. Also, I was standing right near the tank; Miz was standing right near the tank too, but in this configuration her hind legs were several feet from the tank. In the distance between her hind feet and the tank the electric field in the soil (produced by the ground current) could develop plenty more potential than my body would.
To fix the problem, I installed another ground rod near the tank and disconnected the green wire from the neutral in the service box. Then I connected the green wire of the heater to the ground rod--nothing else. That worked for many years. Eventually, I got "Salute", a thoroughbred gelding, and had the same problem. To fix it, I had to install another ground rod on the other side of the tank and connect it to the green wire which is connected to the original ground rod.
But as I pointed out before, I've seen it done wrong far to often to actually trust the colors to be right.
