To summarize. There are two separate 50 AMP 115 volt circuits in a "50" AMP configured 5th wheel. Allowing a set of appliances to draw up to 50 amps on one leg and another different set of appliances to draw up to 50 amps on the second leg simultaneously up to a total of 100 AMPS. Thus allowing multiple power hog appliances to be run simulatanowusly. Whether the two 115 V legs are out of phase or not doesn't matter because no 230 or 240 V appliances are used in 5th wheels.
I use a 220 volt appliance in my camper. It's a 4,000 watt heater I can't run it when hooked up to 30 amps but I can when I use 50 amp. I don't live in a cold part of the country but it's done the job down to 25 degrees during winter without having to use the furnace.
My camper was originally 30 amp but I converted it to 50 amp. Here's where you by the book guys will get upset. I use 10/4 wire with 50 amp plug and receptacle. Looks like 10/3 so it looks like I'm using 30 amps at the pedestal plus it's light weight and easy to handle. I installed a new electrical panel with a 30 amp main in the basement. I run all the factory electrical off one leg leaving me the second leg for additional appliances/devices. All additional circuits use properly sized wire and appropriate breakers for the load.
I can never draw more than 30 amps as determined by the new main breaker so 10/4 wire is adequate. My "exposure" is from the pedestal to my new panel. The possibility of a problem on that run is remote but admittedly not zero.
I wouldn't use 10/4 on a RV originally equipped with 50 amp service unless I was able to swap the main breaker down to 30 amps.
* This post was
edited 06/15/12 04:10pm by Beaux Duke *
I suppose the bottom line is the same as why your stick & brick house has increased from the very low amperage when electricity was first installed, to 100 amp service, to 200 amp service, and from 115 to 230 volts.
Or, the same reason your vehicles went from 6VDC to 12VDC, and aircraft use 28VDC.
Look at the wiring in a 1954 (6VDC) Chevrolet, then compare it to the wires in a 1955 Chevrolet (12VDC). They were able to reduce the amperage load by about 1/2 by doubling the voltage. Reducing the amperage means you can use smaller wires. That saved a LOT of copper and weight.
Which brings up an interesting thought: Are the new all-electric coaches wired for two 50 amp/110VAC circuits, or one 100 amp/220VAC circuit?
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To add to the pot stiring: In both cases i.e. 30 amp or 50 amp, the unit should never reach that maximum current because good design and the National Electrical Code both require that electrical circuits are never to be loaded beyond 80 per cent of the full load. This is for fire safety reasons. So the max you should read with a good ampmeter correctly placed in line with the current or by using a quality clamp on meter is 40 amps on a 50 amp leg and 24 amps on a 30 amp leg.
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