How do the two 120 volt lines from the power grid become 240 volts when joined together?

Answer 1

Canada and US - Visualize it the other way around. The transformer that feeds your house has a primary of 7200 volts. The secondary voltage is 240 volts. This secondary voltage is a split voltage. There are 3 bushings coming out of the transformer on the secondary side. The two outside bushings have the 240 volts on them. The position of the center bushing splits the 240 in to two 120 volts. This center tap is then grounded and becomes the neutral of your house wiring service. L1 to N = 120 volts, N to L2 = 120 volts, and L1 to L2 = 240 volts.

Answer 2

Do you mean tying two breakers together or tying two 120v wire together. You can tie two breakers together with a breaker tie bar if they are each on seperate legs of the panel and yes you will then have 240. If you are talking about tying 2 120v WIRES together BE CAREFUL! If those two wires come from different 120v legs of the panel you will have a direct short and a pretty serious spark to put it mildly. You should only tie 2 120v wires together that are on the same circuit. And you'll still have 120 at that point

Answer 3

When two 120 volt lines from the power grid are joined together, they are 180 degrees out of phase with each other. This means that when one line is at its peak voltage, the other is at its minimum voltage. By combining these two lines, the potential difference between them adds up to 240 volts, resulting in a 240 volt supply.