What is voltage of 50 amp service?

[MrPalazzo]

Good morning, ryno. Anyone can be wrong. I’ll give you another example. There’s a county RV park in Norman, OK where we stay when my wife visits her family. They have a few 50 amp sites and a lot of 30 amp sites. It’s set up so that services are between two sites and it’s never crowded. I have a ‘Y’ cable with two 30 amp, 120 volt, male RV Plugs on the arms and a 50 amp female on the leg. I plug the two 30’s into two separate 30 amp outlets and my RV power cable into the 50 amp female. My inside panel reads 50 amps, and I monitor L1 and L2 on the other panel. I thought that it was 120, but really don’t care. It provides the necessary 50 amps, and works for me. I have similar results with a 50 amp parallel kit and two 3500 watt remote control generators.

while you won't get the full '100 amps' of usable amperage you would get from the 50amp RV outlet, you will only be getting 60amps from the two 30amp outlets, though that's probably still plenty for most any needs. We've done this many times at disparate places or private parks where there is only 30amp outlets available - the adapter works very well for these situations.
Yes, the 50amp outlet would be 240v outgoing, but your RV is most likely only making use of two 120v HOT legs coming into your Main Panel. When you make use of the dual 30amp outlet adapter, you are simply doing the same with two 30amp HOT Legs, sharing those across your RV's main panel - 30amps on each side, rather than 50.

 

[Oneilkeys]

Good explanation TurnerFam, I only have one issue. It seems in your final paragraphs that you are indicating that most people do not need surge protectors because they are not likely to run into electrical issues that will damage their coach. I have two events that caused me to reevaluate that assumption and purchase a surge protector. The first one was at a campground on the AlCan Highway. I had a Class C with a heat pump while plugged into a 30 amp circuit and ran my heat pump that night to save my propane. I didn’t realize that the campground was “off grid” and running on a generator for its power. Sometime during the night the generator shut down - probably slowly. The result was that it blew my A/C and I was without it for several months on my trip to Alaska. Since I was on generator power, I considered this an isolated incident that would never happen to me again, so I did not purchase a surge protector. Two years later I was plugged into 30 amp Power at another campground during a lightening storm. When I tried to unhook in the morning, I found that my cord was melted to the socket in my RV. I has to disassemble the 30 amp socket and remove it still attached to the cord before I could leave. I considered myself very lucky that the melted cord and socket were the only issue. I could very well have had a serious fire right underneath the bed. After replacing the socket and purchasing a new Cord, I also purchased a PD surge protector. It took two, but I learned my lesson. I will never again be without one.

 

[Brabo-THOR]

50 amp service

Tell your electrician that you want a NEMA 14-50R, which is the receptical that you need. Each “hot” leg can have a 30amp breaker as your coach will not draw any more than that and if you plan on leaving it plugged in for extended periods the draw will be a lot less.

 

[abjbrtd]

Interesting thread, I had to rethink our setup

Anybody else have a 360v 130a system?
Yep we plug into the 50a AND 30a outlets.

I still prefer to think our rv has

2 120v 50a circuits in 1 sheath
and
1 120v 30a circuits in 1 sheath




FYI: all the campgrounds we've been in lately don't even ask if we have/need 50a or 30a

 

[16ACE27]

Interesting thread, I had to rethink our setup

Anybody else have a 360v 130a system?
Yep we plug into the 50a AND 30a outlets.

I still prefer to think our rv has

2 120v 50a circuits in 1 sheath
and
1 120v 30a circuits in 1 sheath




FYI: all the campgrounds we've been in lately don't even ask if we have/need 50a or 30a

360 Volts? "I don't think so, Tim"

Still only a 240 VAC supply.

 

[Chuckysbak]

Something to think about!

 

[16ACE27]

Something to think about!

What are we supposed to be thinking about?

 

[cavie]

Interesting thread, I had to rethink our setup

Anybody else have a 360v 130a system?
Yep we plug into the 50a AND 30a outlets.

I still prefer to think our rv has

2 120v 50a circuits in 1 sheath
and
1 120v 30a circuits in 1 sheath




FYI: all the campgrounds we've been in lately don't even ask if we have/need 50a or 30a

OK, this need explanation

 

[cavie]

What are we supposed to be thinking about?

I'm think he is referring to the 360 130 comment. I have no clue what that is about!!

 

[Chance-THOR]

while you won't get the full '100 amps' of usable amperage you would get from the 50amp RV outlet, you will only be getting 60amps from the two 30amp outlets, though that's probably still plenty for most any needs. We've done this many times at disparate places or private parks where there is only 30amp outlets available - the adapter works very well for these situations.
Yes, the 50amp outlet would be 240v outgoing, but your RV is most likely only making use of two 120v HOT legs coming into your Main Panel. When you make use of the dual 30amp outlet adapter, you are simply doing the same with two 30amp HOT Legs, sharing those across your RV's main panel - 30amps on each side, rather than 50.

The concern I’d have is that two separate 30-Amp outlets in a campground could be on same phase, whereas 50-Amp service must have L1 and L2 on different phase to create the 230 Volt when wired correctly. It’s probably not a big risk, but you could end up with 60 Amps on neutral, whereas with normal 50A service you don’t exceed 50 Amps on neutral.

 

[16ACE27]

OK, this need explanation

Well you know it has to be a MOD, no RV is built that way. Although he started out with a Class C I think at some point to moved to a Hurricane.

I suspect it was a 50A rig with two Air Conditioners. Maybe he installed a third Air Conditioner and wired it to a separate 30A plug?

 

[cavie]

The concern I’d have is that two separate 30-Amp outlets in a campground could be on same phase, whereas 50-Amp service must have L1 and L2 on different phase to create the 230 Volt when wired correctly. It’s probably not a big risk, but you could end up with 60 Amps on neutral, whereas with normal 50A service you don’t exceed 50 Amps on neutral.

Now you did it. You went and opened that can of worms! I'll make a double batch.

 

[MrPalazzo]

The concern I’d have is that two separate 30-Amp outlets in a campground could be on same phase, whereas 50-Amp service must have L1 and L2 on different phase to create the 230 Volt when wired correctly. It’s probably not a big risk, but you could end up with 60 Amps on neutral, whereas with normal 50A service you don’t exceed 50 Amps on neutral.

no, but this 'can of worms' is easily explained:

Most any RV that is 50amps does NOT need the two HOT Legs to be in different 'phases', as that only applies to 240v double-pole breakers, such as for a residential clothes dryer. Of the very few RVs that do have a need to power a 240v appliance, they may have to rethink using a dual 30/30 to 50amp adapter...

Most any RV that is 50amps is simply using the two HOT Legs separately, just as if it had two separate Main Panels of 120volts each.
The NEUTRAL then acts as the same neutral used in any 120v outlet, a 3-wire design.

 

[16ACE27]

no, but this 'can of worms' is easily explained:

Most any RV that is 50amps does NOT need the two HOT Legs to be in different 'phases', as that only applies to 240v double-pole breakers, such as for a residential clothes dryer. Of the very few RVs that do have a need to power a 240v appliance, they may have to rethink using a dual 30/30 to 50amp adapter...

Most any RV that is 50amps is simply using the two HOT Legs separately, just as if it had two separate Main Panels of 120volts each.
The NEUTRAL then acts as the same neutral used in any 120v outlet, a 3-wire design.

Not quite: In a regular 120 VAC 3 wire circuit the neutral carries the exact same current load as the hot.

In a 240 VAC 4 wire circuit the neutral only carries the difference in current load of the two hot legs. If the two hot legs had the same current load, no current would flow on the supplied neutral.

 

[MrPalazzo]

yes, the 240v scheme needs a balance carrying 'Neutral' ... when, or if, the two HOT Legs are not sharing the same amperage load, which they more than likely NEVER do within an RV setting. The Main Breakers, the two 50amps that have a common trip handle, share this NEUTRAL wire, back to the Shore Power outlet.

Within the RV's Main Panel, though, and since all breakers are traditionally only single 120v 3-wire circuits, the Neutral acts as though it does in any other typical household outlet.

So, there is incoming 240v power, yes, but the Main Panel doesn't 'provide' 240v service to any of the single 120v circuit breakers, at least in the typical RV wiring scheme.


I think I have too much time on my hands!! Fun.

 

[cavie]

yes, the 240v scheme needs a balance carrying 'Neutral' ... when, or if, the two HOT Legs are not sharing the same amperage load, which they more than likely NEVER do within an RV setting. The Main Breakers, the two 50amps that have a common trip handle, share this NEUTRAL wire, back to the Shore Power outlet.

Within the RV's Main Panel, though, and since all breakers are traditionally only single 120v 3-wire circuits, the Neutral acts as though it does in any other typical household outlet.

So, there is incoming 240v power, yes, but the Main Panel doesn't 'provide' 240v service to any of the single 120v circuit breakers, at least in the typical RV wiring scheme.


I think I have too much time on my hands!! Fun.

YEP!

 

[16ACE27]

yes, the 240v scheme needs a balance carrying 'Neutral' ... when, or if, the two HOT Legs are not sharing the same amperage load, which they more than likely NEVER do within an RV setting. The Main Breakers, the two 50amps that have a common trip handle, share this NEUTRAL wire, back to the Shore Power outlet.

Within the RV's Main Panel, though, and since all breakers are traditionally only single 120v 3-wire circuits, the Neutral acts as though it does in any other typical household outlet.

So, there is incoming 240v power, yes, but the Main Panel doesn't 'provide' 240v service to any of the single 120v circuit breakers, at least in the typical RV wiring scheme.


I think I have too much time on my hands!! Fun.

And not enough good information. Neutrals do not go to any standard breakers in either a house or RV. And there are no "240" VAC or "120" VAC breakers; 240 VAC are ganged double breakers, one for each hot leg which are connected to the two "hot" busses. Then there are neutral busses and ground busses.

 

[dkoldman]

after much experience with RV electrical, I'll add my learned info:

Now, electricians will say that this is not technically 'correct' to say that 50amp RV service is actually 100amps of 120v power, but since most every typical 50amp RV only has 120v single breakers within it's Main Panel, the end outcome is that the RV owner has access to using up to 100amps of power.
While a select and very few larger RVs might have a double-pole breaker within their Main Panel to power a 240v clothes dryer, it's not common.
The electrical industry has always assigned 'Amperage' as a language that only pertains to the number on the end of each Breaker, whether that breaker is a single pole 120v or a double-pole 240v type, which creates confusion for the RVing public, since few of us have had 'electrical education', at least in this 'mobile' environment where we have to be aware of 'what' type of outlet we are plugging into.

TurnerFam

This is outstanding post . Hope you don't mind as I cut & pasted it in its entirety to my RV SOP Best Practices and Procedures notebook I am keeping for myself.

I actually installed my own 100 AMP Sub Panel in my driveway (see picture; that I can't get to rotate on this site . It has 50amp Double Pole, 30amp, and 20 amp breakers. I always viewed as it can handle a max of 50 amps on the Double pole 50 amps breaker or sub panel's breaker would trip? If I use a load on the 30 amp breaker, or 20 amp breaker at the same time as the 50 amp breaker, the subpanel will only trip if I exceed 50amp, 30amp, or 20 amp on each breaker respectively? However, since I have 60 amp Double Pole Breaker in the the Main Breaker box not pictured, if the combination of any of the breakers in use hit 60 amps total load, then my main breaker 60 amp Double Pole Breaker in the the Main Breaker box will trip? If one leg trips don't both trip? Am I thinking right or is it that the Double Pole breakers will not trip until 100amps or 120 amps respectively?

FWIW, I have run everything trying to get it trip but no luck ; so it is prolly a mute point, but I would like to be clear on how it works.

Additionally, my coach has power management system; so it knows when the source power is only 30amps or 20 amps so it helps to manage what is running inside. i.e. a 2nd AC will not come on when it knows source is 30 amps or less.

For OP....

You may have got more than you sought with your question, but my advice to you is one that I follow. When I see Cavie and Retired Master Electrician. It is pretty simple & cheap to just do what he advises You can literally take it to the bank

 

[cavie]

turnerfam

this is outstanding post . Hope you don't mind as i cut & pasted it in its entirety to my rv sop best practices and procedures notebook i am keeping for myself.

I actually installed my own 100 amp sub panel in my driveway (see picture; that i can't get to rotate on this site . It has 50amp double pole, 30amp, and 20 amp breakers. I always viewed as it can handle a max of 50 amps on the double pole 50 amps breaker or sub panel's breaker would trip? If i use a load on the 30 amp breaker, or 20 amp breaker at the same time as the 50 amp breaker, the subpanel will only trip if i exceed 50amp, 30amp, or 20 amp on each breaker respectively? However, since i have 60 amp double pole breaker in the the main breaker box not pictured, if the combination of any of the breakers in use hit 60 amps total load, then my main breaker 60 amp double pole breaker in the the main breaker box will trip? if one leg trips don't both trip? am i thinking right or is it that the double pole breakers will not trip until 100amps or 120 amps respectively?

fwiw, i have run everything trying to get it trip but no luck ; so it is prolly a mute point, but i would like to be clear on how it works.

Additionally, my coach has power management system; so it knows when the source power is only 30amps or 20 amps so it helps to manage what is running inside. I.e. A 2nd ac will not come on when it knows source is 30 amps or less.

for op....

you may have got more than you sought with your question, but my advice to you is one that i follow. When i see cavie and retired master electrician. it is pretty simple & cheap to just do what he advises You can literally take it to the bank

yes/no your RV 50 will trip first.

yes

no

 

[clev-THOR]

There's been a lot of good discussion and some good information on this thread. One thing, though, is the 100 amp thing. It has come up in the past, is also brought up in this thread, and has probably caused some confusion, at least for me. Here's how I understand it; please correct me, and tell me if and where I'm wrong. In basic terms, to me, each hot leg is capable of carrying 'up to' 50 amps. And yes, that is 100 amps, but L1 + L2 cannot be greater than 50 amps. Correct? If L1 is reading 30 amps, then L2 cannot provide more than 20 amps. Our RV's have a 50 amp breaker, so there can never be 100 amps available for use. If that is not correct, please take a minute, use basic terms and help me understand this.