Actually, the currents are added. The effect is subtraction.

One leg has a -1 vector tagged to it so when adding it becomes subtraction.

Remember in the US and many other places the two voltages are 180 degrees
out of phase with the other.

Martin

Martin H. Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
"Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer
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On 6/9/2010 8:38 AM, Puckdropper wrote:
(Doug Miller) wrote in
:

In , Puckdropper
puckdropper(at)yahoo(dot)com wrote:
If you're running 2 120V circuits from a 12-3 cable, consider that the
neutral would have to carry twice as much current as it would in most
situations.

No, it doesn't, unless it's installed improperly. Properly installed
(with the two hot conductors on opposite legs of the service), the
current in the neutral conductor is the *difference* of the currents
in the two hots, not their sum. For example, with 11 amps on one leg,
and 7 amps on the other, the current in the neutral is 4 amps, not 18.

Bill, I'm sorry for the incorrect information. After much thought, I
think I can explain why Doug's right. (On opposite legs, the current
draws are going two different directions (on a plot). That's why they
subtract and not add.)

Doug, thanks for the correction.

Puckdropper