Suppose you have 220 volts AC and a load such as an electric fan. Is the current before and after the load exactly 100% similar in value? Are there loads wherein the current can become different before and after the load. If they are all 100% exactly the same. How come the two parallel electric cord glued together commonly used in appliances still has residue magnetic field (like 1.5mG) and they don't cancel 100%. They theoretically should since the current before and after the load is exactly the same so the magnetic field is exactly 180 degrees out of phase so 0 mG output should suppose to occur.
Thanks.
Dave