50 amp service

[rickvikki]

Hello everyone:

We have a 40 ft Tiffen Phaeton Motorhome. We are plugged into 50 amp service but our AC voltage indicator inside MH is only at 110. Any ideas as to what is wrong? I know this is kind of vague but we are "vague" when it comes to electricity 🙂

Thanks Vikki and Rick

[AllegroD]

Get a Kill-A-Watt (digital, no needle to stick) for inside and a digital volt meter to use at the pedestal.

[nomad297]

What is your voltage on each leg at the pedestal?

Bruce

[lanerd]

wa8yxm wrote:
15,20 and 30 amp service are like this

Neutral <-120VAC-> hot

50 amp service is like this

L1<-120VAC->Neutral<-120vac->L2
L1<--240 Volts alternating-->L2

There may be one, and only one thing, in MOST motor homes (there are always exceptions) that needs 240 volt, that is an Energery management system.. If it sees 240 volts L-1 to L-2 it knows you are on 50 amps. Else it assumes 30.

So why do they do this? Well, has to do with the physics of electricity.

IF you pump 50 amps down L-1 and let's say it looses 2 volts

You pump another 50 amps down L-2 and it looses 2 volts

How much is lost on the "Return" (Neutral) line,, answer, Not a thing since no current is flowing in the neutral. You just cut your voltage drop in half

But if you pump that same 50 amps down JUST ONE LEG, two volts is lost each way.

(Sorry can not ascii draw this) But another way of putting it is efficiency.

If you want to confirm 240 volts, the easiest way (NOTE There is Danger here) is to open the power distribution center and measure the voltage between the two MAIN breakers. it shoudl say 220 in your case (230-240 is excellent 220-250 is acceptable)

John, this is waaaaay too much info for the OP who obviously has no electrical experience and/or knowledge and just adds to the confusion.

Vikki, you need to get an electrician (or knowledgeable person) to inspect the pedestal and your connections.

Ron

[wa8yxm]

15,20 and 30 amp service are like this

Neutral <-120VAC-> hot

50 amp service is like this

L1<-120VAC->Neutral<-120vac->L2
L1<--240 Volts alternating-->L2

There may be one, and only one thing, in MOST motor homes (there are always exceptions) that needs 240 volt, that is an Energery management system.. If it sees 240 volts L-1 to L-2 it knows you are on 50 amps. Else it assumes 30.

So why do they do this? Well, has to do with the physics of electricity.

IF you pump 50 amps down L-1 and let's say it looses 2 volts

You pump another 50 amps down L-2 and it looses 2 volts

How much is lost on the "Return" (Neutral) line,, answer, Not a thing since no current is flowing in the neutral. You just cut your voltage drop in half

But if you pump that same 50 amps down JUST ONE LEG, two volts is lost each way.

(Sorry can not ascii draw this) But another way of putting it is efficiency.

If you want to confirm 240 volts, the easiest way (NOTE There is Danger here) is to open the power distribution center and measure the voltage between the two MAIN breakers. it shoudl say 220 in your case (230-240 is excellent 220-250 is acceptable)

[nomad297]

What is your voltage on each leg at the pedestal?

Bruce

[kcmoedoe]

Did you just move to a different location? It sounds like there is a brown out condition if you didn't move. If you did move, sounds like the power supply to the pedestal is bad or your connections are bad. If you are in an RV park, find someone with a multimeter who knows how to use it. If the voltage at the pedestal is low (below 114 volts), either move or have the park get it corrected.
As for Dutch's post, that would be incorrect. If a park was wired that way, the voltage would be in the 120 range. He is correct that the RV would see it as a 30 amp connection and the energy management system would operate on that assumption.
It is my experience that it is about as safe to rely on these forums for electrical advice as it would be to just wet your finger and stick it in the socket to see if the circuit is live. Electricity is too dangerous, and the equipment that can be damaged too valuable, to rely on anything other than someone who is actually experienced and on site to see what is really going on.

[rickvikki]

Sorry everyone: I guess we said it wrong in our question. All summer we have been plugged into 50 amp, but just today, I went to use microwave and it barely operates, same with toaster oven and coffee maker. We are not electrical minded at all, but have had this voltage reader always plugged in inside motorhome and it always sat at about 120 and needle never moved much when operating microwave etc. but today something has changed and is barely drawing power to microwave and coffee maker worked but dropped the needle to the bottome. I hope this makes sense?

Vikki and Rick

[Dutch_12078]

Does your voltage indicator normally show about 240 volts when you're plugged into a 50 amp outlet? If it does, then you may be in a park that "cheated" when upgrading their sites to 50 amp, by just jumpering the two hot pins together and connecting them to a single 120 volt 3-wire supply instead of proper split phase 4-wire supply. An RV power management system would typically see that as a 30 amp supply, even though the stanchion breaker may be 50 amps.

[holstein13]

rickvikki wrote:
Hello everyone:

We have a 40 ft Tiffen Phaeton Motorhome. We are plugged into 50 amp service but our AC voltage indicator inside MH is only at 110. Any ideas as to what is wrong? I know this is kind of vague but we are "vague" when it comes to electricity 🙂

Thanks Vikki and Rick

Why do you feel something is wrong?

[mikim]

Ideally voltage should be 120 volts + or - 5%. That figures out to 114 volts to 126 volts. Anything outside of these parameters can be hazardous to your electrical items especially electronics.

[rk911]

rickvikki wrote:
Hello everyone:

We have a 40 ft Tiffen Phaeton Motorhome. We are plugged into 50 amp service but our AC voltage indicator inside MH is only at 110. Any ideas as to what is wrong? I know this is kind of vague but we are "vague" when it comes to electricity 🙂

Thanks Vikki and Rick

nominal voltage will always be 110-120.

[hanzfranz60]

Greetings fellow RVer!

Voltage in RV parks can range from 104 up to 132 volts, and that is okay. Either of those readings is fairly on the high and low side, but no damage will come unless they are above or below that range. RV EMS units are designed to cut power at about those settings so damage is not done to appliances and electronics.

Everyone thinks voltage should be right at 120, but that is rarely the case when it comes to RV electrical pedestals. This comes from an electrical background, working in RV parks, and staying in many over the past six years of full timing.

So, don't worry. You are okay and 110 volts. If you don't have an EMS unit like one from Progressive Industries, do yourself a favor and get one. The $350 you will spend could save you thousands. It has saved my but three times so far!!

Give a shout if you have further questions!

[HappyKayakers]

Nothing is wrong. You're supposed to have 110 inside whether you have 50, 30 or 20 amp service.