is where we seem to be heading. The original question is now heading into Electrical 101. I spent a period of my past life working with commercial generators for Verizon in New England.
Here are some simplifying facts:
For engineers and industrial purposes the designations 'x', 'y' and 'z' are significant. For our purposes L1, L2, Neutral and Ground work just fine.
In the RV power pedestal world we see the following with a volt and amp meter is all is wired correctly:
1/ A 30A service is just that. 30 available amps at 120VAC. The danger lies in the fact that the hot and neutral can easily be reversed coming into the coach. I must confess, at this very moment I do not recall which lead is which. It has been some time since I have wired one. I ALWAYS look up the spec in a file I have on hand before I do any work on a 30A service.
2/ A 50A service is made up of 2 50A, 120V legs called L1 and L2. The total available amperage to your RV is 100A. Your service panel is designed and wired to only give you 120V service to your outlets. You may or may not see 240VAC at the pedestal between L1 and L2, but to Neutral/Ground and L1 OR L2 you WILL see 120VAC. (Only a few high end RVs use a true 240V service as is in our stick homes. Our coach generators produce 2 each 120VAC legs in phase. You will read 0VAC between them.)
The size of the Neutral is critical depending on which type of 50A service is supplying the pedestal. Because, mechanically speaking, it is more practical to wire L1 and L2 at the host service panel this is what we find at the campgrounds. The Neutral can be one wire size smaller than the hot legs because of the 'neutralizing' nature of the normal wiring practice. The neutral will not see more than 50A. If, however, L1 and L2 are in phase the Neutral has the potential of seeing 100A.
Just a word of caution. It is a good practice to check that the Neutral measures 0 ohms to the Ground across the pedestal outlet terminals. The loss of the Neutral is often very damaging to our RVs unless they are equipped with special protection circuitry.
I must stop now to join my DW for morning coffee. I hope I have helped.
Rick
Here
. (full time volunteers)
come from L1 and L2 so when you check it the voltage between X and Y should be 240-Volt. This service provides 12,000 watts. On a FAKE 50-amp they use L1 or L2 for BOTH side (X & Y) of the HOT leads therefore the voltage between X and Y will be 0-Volt. This service will give you 6,000 watts. Better than 30-amp with 3,600 watts but it is NOT a TRUE or CORRECTLY WIRED 50-amp service. 
Linear Mode
