This ex-Ham [from age 12] wired our new House to Code. With that in mind, here's a few details. I use 2 - 1,500 Watt Heaters intermittently to heat the entire super-Insulated, ~1,750 sq. ft. House, since I've not yet connected the Radiant Floor, powered by an Electrical Hot Water Heater.
1. Assuming 115 VAC [vs. 110 VAC or 120 VAC], 1,500 Watt Heaters draw ~13 Amps. 750 Watt Heaters draw ~6.5 Amps. For the sake of argument, a 1,500 watt and 750 Heater operated simultaneously would draw ~19.5 Amps.
Lower Park Pedestal Voltage causes the inverse of higher current to be drawn. Since Breakers open off of current, Breakers operated right at their limit might work in some situations, or at some temperatures, but not in other scenarios.
2. 2 - 1,500 Watt Heaters would draw ~26 Amps. Along with other Coach 'background' electrical draw in addition to this, it's easy to see why a Park Pedestal 30 Amp Breaker might open.
3. If deemed necessary, once the wiring of any given Coach is figured out, I would add several 15 or 20 Amp, breakered, different-colored Receptacles that bypass Inverter and other Electronics. Or, as mentioned above, use 20 Amp Receptacles with the 'T' Neutral [left-most] Slot to distinguish them. There's a lil Hot Tub Breaker Box that holds several, additional Breakers if there's no Breaker Box room elsewhere. Note that there's '1/2 size' [width] Breakers, too, for retrofitting additional Breakers safely if Breaker Box space is tight. Always use ONLY the same Manufacturer and the same Series of Breakers.
The separate, adequate Extension Cord run out to the Park Pedestal works, too.
4. Some Appliances have an 'inrush' current surge, and can trip Breakers intermittently as they require extra current only at turn on. Microwaves and Blenders/Food Processors come to mind. This can be aggravating to track down because Coach Breakers seem to work some times with other Electrical Loads turned on, but not at other times.
5. 12 Gauge [20 Amp] or 16 Gauge [15 Amp] Romex and Wire ratings are intentionally conservative. They actually can carry more current DEPENDING on temperature and whether they're in bundles, etc.. I've never heard of this ~80% Duty Cycle concept mentioned above. 15 Amp Breakers and Wire can carry that Load continuously, at least as I ever learned it, and as my Electrical Contractor Pal taught me the fine details of.
AWG Wire Charts
As some other A-R, safety-minded Contributors mention here, I would add intrinsically-safe Coach Receptacles [if necessary] that simply prevent any chance of overheating and failure. Then, Heaters can be chosen based on size; cost; style, and other factors. We have a Dog, so I realize Heaters can be knocked over accidentally. I stabilize them accordingly on a square of inflammable Tile in my lil Trailer, and keep Fire Extinguishers and Smoke Detectors in good order.
I plumbed our Colorado Solar House for Propane, but then changed over major Appliances to Rural Grid-supplied Electricity. Per 1,000 Heating BTUs generated, Electricity is cheaper than Propane. However, this depends on local Electricity cost, along with Taxes and Fees tacked on.
An important detail: virtually 100% of Electricity is converted to heat by Electrical Heaters. Although I don't see a Conversion Efficiency for, say, Atwood Propane Furnaces on line, this Conversion Efficiency to Heating BTUs is significantly
less. Heat goes out the Exhaust Vent.
From the Website linked below:
'Based on these calculations, I am getting costs of:
Propane: $0.0315 / 1k BTU
Oil: $0.0284 / 1k BTU
Electric: $0.0239 / 1k BTU.
I was always told that electric heat is going to be much more expensive than oil or propane, but this math is not showing this to be the case based on costs in our area.'
House Heating ~ Electrical vs. Propane Calculations ~ 2012