Old-Biscuit wrote:
valhalla360 wrote:
Old-Biscuit wrote:
100' with 50A #6 power cord 40A load will have roughly a 3-4 Volt drop from source to RV
120VAC....116/117VAC
You are assuming the house has good strong voltage and it won't sag under heavy load (and you are thinking 120v when a 50amp is 240v)
If the outlet is 50am, it should be 240V but don't be surprised to see 220v at the outlet.
At 220v, 20amp per leg jumps to around 22amps per leg (assuming the air/con units are on separate legs). So each leg sees 22amp @ 110v at the outlet and with voltage drop around 108v at the RV.
That's marginal for me where I start considering if should deploy the voltage booster or break out the generator.
If for some reason both air/con units are on the same leg, the amps doubles on that leg and voltage drop results in around 106v.
This ignores bad connections or issues with the wiring in the house, so you could easily lose another 2-3 volts in real life.
It's only 240VAC if you measure voltage across BOTH Hot Legs
Each Leg is 120VAC rated for 50 amps
Each leg feeds 1/2 of RV Main AC Panel Buss
40A on one leg will drop 120VAC down to roughly 116/117 VAC
Each leg can handle that amp load w/o issue
240VAC only comes into play IF the RV has a 240VAC appliance which very few have such appliances
Read thru my entire post...I clarified how the legs work. I was just clarifying that your post omitted the first part where 50amp is 240v but you get 2 legs at 120v.
But that wasn't the point.
The point is 120v is a nominal rating and it's not uncommon for the power at the outlet to be below the nominal rating. Power entering the house can be 5% below the nominal rating (about 114v) then from the breaker box to the outlet, you often have voltage loss due to wiring runs and connections. So it's not uncommon to find 110v (sometimes lower) at the outlets. Add on a 100ft extension cord and you can see very marginal voltage under load.
