HELP AC Outlets blowing devices!

CA Traveler wrote:

wnjj wrote:

JimM68 wrote:
ok, read the first half of the first page. Rig is a 50 amps with an open neutral.
OP is not qualified to fix this.

Things will continue to blow up. Recommend an electrician. unfortunately, most electronic / computer types just have no clue about a/c power, particularly 2 phase stuff. (and yes, generally 50 amp rv power is 2 phase, even though it doesn't need to be and is not specified to be.

If 50 amp RV power uses a 4-pin plug, it had better be 2-phase. If both hots are on the same phase the neutral wire needs to handle twice the current which it likely isn't capable of. The only safe way to use such a system with a neutral wire sized for 50 amps is to use a double pole 25 amp breaker.

Both of these posts are incorrect.

50A RV power is in fact single phase. 240/120V power comes from a SINGLE center tapped winding on a transformer with the center tap being the neutral. As such current in the winding and hence both hot legs flows in one direction or the other and can only be single phase.

The neutral does in fact handle only the difference of the two hot leg currents which with the dual 50A CB restricts the neutral current to 50A in this SINGLE PHASE system.

50A RV power is not multiple phase power like you might find with a Y or Delta configuration.

50A RV power is also the same at the typical household power except that the typical home has a bigger panel like 200A. Otherwise both are single phase.

It's very common but incorrect to refer to 50A RV power as 2 phase. Split phase is a good description of 50A power.

Ok. What I called 2-phase is actually called split-phase, but what I wrote about the wire sizes is still true which is the important point. Split-phase operates like the now obsolete 2-phase did except 180 degrees out of phase instead of 90.

In both cases the current flowing in each of the hot wires is out of phase with each other (hence why I mistakenly called it 2-phase). It looks to me like the only reason we don't call it 2-phase today is simply to avoid confusion with legacy 2-phase (90 degree) systems or maybe the technical definition of phase is that 180 is considered the same as 0.

Obviously 180 degrees allows for full neutral sharing where 90 doesn't. Close enough?

Regardless, not the point of this thread since the OP's trailer is wired for split phase.