In determining which size wire to use, what load do we enter when calculating voltage drop when adding a 50 amp RV site when the electric service is a 240 volt, 50 amp breaker and RVs technically run on 120 volts? Do we count the RV as 50 amps, or can we count it as just 25 amps since the RV essentially has two 120 volt, 25 amp circuits?

I don’t know if your RV is somehow different, but generally, 50A RV’s are two 120 volt 50 amp circuits.

I'm not following. What do you mean 'which wire', and what does voltage drop have to do with it?

Use 240 volts and 50 amps in the calculator. 25 amps would be incorrect.https://www.myrv.us/electric/Pg/50amp_Service.htmhttps://www.customcableusa.com/pages/voltage-drop-calculatorDon't get all confused because there is an RV plugged into the standard common NEMA 14-50 outlet. No different calculation should be used to accommodate what is plugged in.

50A is 240/120V 4 wire which is used as 2x 50A circuits. 240V appliances are not the norm for a RV. The 2 hot wires and neutral are each rated for 50A which is the maximum. ie You have a total of 100A @ 120V for the 2 circuits or 12KW.Use 50A load for the wires which are normally 6ga unless long distances are involved.

2oldman wrote:I'm not following. What do you mean 'which wire', and what does voltage drop have to do with it?OP, explained her question perfectly clearly. OP, you would use the V and A for the service (IE the main breaker in the sun panel which you state as 50A, 240V). Those are the values to plug into a voltage drop calculator. Theoretically you could use “all” the power that a 50A 240 main breaker would handle, with a 50A RV setup which is 50A 120v pulling separately off of each leg of the 240v service.

Calculating voltage drop | Good Sam Community

CA_Traveler
Explorer III
Apr 07, 2023
50A is 240/120V 4 wire which is used as 2x 50A circuits. 240V appliances are not the norm for a RV. The 2 hot wires and neutral are each rated for 50A which is the maximum. ie You have a total of 100A @ 120V for the 2 circuits or 12KW.

Use 50A load for the wires which are normally 6ga unless long distances are involved.
time2roll
Nomad
Apr 07, 2023
Use 240 volts and 50 amps in the calculator. 25 amps would be incorrect.

https://www.myrv.us/electric/Pg/50amp_Service.htm

https://www.customcableusa.com/pages/voltage-drop-calculator

Don't get all confused because there is an RV plugged into the standard common NEMA 14-50 outlet. No different calculation should be used to accommodate what is plugged in.
2oldman
Explorer II
Apr 07, 2023
I'm not following. What do you mean 'which wire', and what does voltage drop have to do with it?
nickthehunter
Nomad III
Apr 07, 2023
I don’t know if your RV is somehow different, but generally, 50A RV’s are two 120 volt 50 amp circuits.

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