50amp on 120/208 service

CA Traveler wrote:

DrewE wrote:
Although the two phases are 120 degrees from each other, the phase to phase waveform still works out to be a sine wave, so it's "normal" single phase power albeit at a lower voltage. There are plenty of single-phase motors that are rated to operate at either 208V or 240V (and likewise plenty that are not so rated).

Sine waves for sure. But a 240V motor sees that the combined voltage and amps are 120 degrees out of phase with each other. So definitely no longer 240V single phase.

As long as the motor and it's load is designed for both power sources then all is good. Appreciate the input.

From the motor's point of view, the voltage isn't out of phase at all since it has no neutral connection. It's just a (single-phase) 208V 60Hz AC power supply; the motor behaves precisely as if it were connected to a variac or similar device set to 208V. The current may not--indeed generally will not--be perfectly in phase because the motor is inductive and has a non-unity power factor; but it's not offset from the voltage in any atypical way. (The current waveform in a constant voltage system, such as the modern electrical grid, is of course determined by the characteristics of the load, and not directly dictated by the supply.)

ScottG wrote:

Cummins12V98 wrote:

HMMMMM, I have a 220V Washer AND Dryer. I also have 220V Cheap Heat.

I'm curious, what happens if you turn on your washer, drier or CH when plugged into 30A (120)?
Or do they just expect us to be smarter than that.. :D

Interesting question.

Some aspects of the appliance might work. Imagine that the control panel and the motor work on 120V and a day later the clothes aren't dry. :h

ScottG wrote:

Cummins12V98 wrote:

HMMMMM, I have a 220V Washer AND Dryer. I also have 220V Cheap Heat.

I'm curious, what happens if you turn on your washer, drier or CH when plugged into 30A (120)?
Or do they just expect us to be smarter than that.. :D

No idea. If I were plugged into just 120 I would not use them. If I need them I would fire off my 220v 6500 Cummins Commercial gen.

DrewE wrote:
Although the two phases are 120 degrees from each other, the phase to phase waveform still works out to be a sine wave, so it's "normal" single phase power albeit at a lower voltage. There are plenty of single-phase motors that are rated to operate at either 208V or 240V (and likewise plenty that are not so rated).

Sine waves for sure. But a 240V motor sees that the combined voltage and amps are 120 degrees out of phase with each other. So definitely no longer 240V single phase.

As long as the motor and it's load is designed for both power sources then all is good. Appreciate the input.

Cummins12V98 wrote:

HMMMMM, I have a 220V Washer AND Dryer. I also have 220V Cheap Heat.

I'm curious, what happens if you turn on your washer, drier or CH when plugged into 30A (120)?
Or do they just expect us to be smarter than that.. :D

Not sure why anyone thought I was going to try to install this myself, but I have 2 professionals installing the plug but not all professionals understand exactly what is required of RV's. They know what an RV plug is and the wiring required. I just wanted a little reassurance that they understood what I hoped they understood and it appears that they do. Hopefully, they will get the work done this week or next and I will be plugged in 30 seconds from the office!

Cummins12V98 wrote:
"NOTHING in yoru RV needs 240 volts (Minor exception if you have an ALL ELECTRIC RV that may not be the case) Everythign is 120 volt"

HMMMMM, I have a 220V Washer AND Dryer. I also have 220V Cheap Heat.

Bottom line I would consult a QUALIFIED Electrician.

No, nothing in my RV needs anything other than 120. Don't need ANY kind of electrician to tell me that.

Cummins12V98 wrote:
"NOTHING in yoru RV needs 240 volts (Minor exception if you have an ALL ELECTRIC RV that may not be the case) Everythign is 120 volt"

HMMMMM, I have a 220V Washer AND Dryer. I also have 220V Cheap Heat.

Bottom line I would consult a QUALIFIED Electrician.

You will note I too suggested a qualified electrician or at least a licensed one. I won't bore anyone with the list of reasons why.

Your 220 Volt W/D is not designed for RC that's a Residential device I'm sure. But it won't mind 208.. Neither will the cheap heat. Just a few less BTUs.

THe element in my water heater says 240 volt (1500 watt) but it works just fine on 120. only 375 Watts though.

Chris Bryant wrote:
FWIW, the heat pump in my Florida house was rated to run on 208 or 240.

This is very common now a days, especially for A/C and heat pumps.

Pure resistance devices (stove, water heater, dryer) will just make less heat.

for reasons of insurance use a qualified electrician.