Originally Posted by Lynkage
A 4 wire outlet (wired correctly) would deliver proper voltage to a 4 wire plug. This is assuming that the plug has been wired for it's intended purpose and not wired as the end user sees fit for their unintended use.
Exactly why I am curious to know what was wrong with JeepMan's friend situation. We know he fried his stuff, but don't know the exact cause yet.
It has been stated that he plugged his 50 amp trailer into a 50 amp 240 volt outlet as it should be.........but something went wrong here. If this statement is precise, then we have to assume the outlet was wired incorrectly as Herk pointed out.
If he however, did use an adaptor like BombDoc did, and plugged into a 240 volt 30 amp outlet, then he also would have shot 240 volts across things not made for it.
It would be good to know which scenario may have happened, for others to learn from it.
I am adding this for future readers and trying to put it simply, as it may be confusing from all the jargon above.
In normal use, a 50 amp trailer plugs into a 50 amp 240 volt outlet. This 240 volt service has two 120 volt hot lines, which make a combined 240 volts. The RV itself, separates the two 120 volt hot lines, and everything inside the trailer works off of 120 volts either on the Line 1 side or the Line 2 side.
A 30 amp trailer plugs into 30 amp 120 volt service. It only has one hot line and everything in the trailer works off of 120 volts.
You always want to make sure you are plugging into a 30 amp 120 volt outlet.....and not a 30 amp 240 volt outlet........for either a 30 amp or 50 amp (using adaptors) trailer above. It's obvious why you don't want 240 volts for a 30 amp trailer..... but when you use a 50 to 30 amp adapter, it will feed 240 volts to both the Line 1 and Line 2 sides if plugged into a 30 amp 240 volt outlet, which are normally separated to only get 120 volts each.