Did I Just Fry My Appliances?
This past weekend I took my dad's 5th wheel to a buddy's farm to hang out for a couple of days. Both of our generators were at our farm a couple hours in the other direction. So, i ran down to the loc...
Forum Discussion
RustyJC wrote:
If the two hot legs are in phase as you describe, there's a real risk of overloading the neutral conductor in your shore power cord. Neutral leg current is the sum of the hot leg currents, but because "proper" 120/240VAC split phase center tap neutral 50A service has the two hot legs 180* out of phase, one leg is mathematically assigned a minus (-) sign. Thus, in a "proper" 50A setup, if both legs were drawing 50 amps, the neutral current would be 50 + (-50) = 0 amps. If it were wired in phase as you describe, then neutral leg current would be 50 + 50 = 100 amps; the neutral conductor is sized for 50 amps, so the potential problem is obvious.
Besides, most power management systems look for 240VAC across L1 and L2 as an indicator that 50A service is available. If they see 0VAC across L1 and L2, they default to 30A service - that's what my system does. By doing so, it prevents the overloaded neutral conductor situation described above.
Rusty
But an adapter to feed a 50-amp trailer from a 30-amp plug does just that. Feeds 120v of the same phase to both legs. Meter it, 120v to ground or neutral. But 0v between the hot's
And our EMS-PT50C doesn't seem care if the hot are phased or not. Shows the same voltage on both legs.
