I've NEVER Been So Mad at a CG!

[Fanukalum]

Will someone turn on all three A/C's, the induction stove top, the convection oven and the heated floors (ie a full load), then go check each leg and the neutral at the pedestal with a ring type amp meter. This will answer the question definitely not theoretically. Do it quick before the breaker trips due to low voltage related to high demand on the grid related to heat!
I actually believe there is a thread on this forum about a guy that was threaten with arrest for opening the pedestal to due this very thing. so be careful out there!

[richard5933]

Originally Posted by twinboat

The neutral only carrier the difference between L1 and L2.

If L1 is carrying 30 amps and L2 is carrying 20 amps, neutral is carrying 10 amps.

If both L1 and L2 are carrying equal amps, neutral is carrying 0 amps.

If L1 is carrying 50 amps, and L2 is carrying 0 amps, neutral is carrying 50 amps.
Neutral never carries more then 50 amps because L1 or L2 would need to supply it and it would trip the 2 pole breaker.

https://www.rvtechmag.com/electrical/chapter3.php

Guess I should have said neutral carries UP TO 50 amps. Thanks for the clarification.

[Persistent]

Originally Posted by richard5933

Probably because that's what people see when they look at the circuit breaker - a '30' or a '50'.

The 50-amp breakers are a double-pole breaker, but often they have only one lever to flip. So, to most people, it looks like a single breaker that says '50' on it.

A 50 amp service is exactly that. The maximum current flow through the service is 50 amps. A 30 amp service is exactly that. The maximum flow through the service is 30 amps.

If you draw 50 amps 115 volts from a 50 amp 230 volt service, you are drawing 50 amps. 50 amps in L1 and 50 amps out the neutral.
If you add 50 amp 115 volts draw through L2, you still have 50 amps flowing. 50 amps in through L1, zero current through the neutral, and 50 amps through l2.

L1 and L2 are out of phase. AC is alternating current at 60 cycles. The flow reverse every 1/30 of a second. The flow is first L1 to L2 then L2 to L1. The flow is 50 amps. No current flows in the neutral.

If the CG ties both L1 and L2 together, it is no longer 50 amp 230 volts. It is 50 amps 115 volts. Both legs are in phase. If you draw 50 amps from each leg, the neutral will be carrying 100 amps. Can you say FIRE! Neither the pedestal breaker, nor the main in your TT will trip.

When both legs are tied together in your TT, you usually are de-rated for current. For instance, your generator may be 30 amps 115 volts or you are using a dog-bone adapter in a 30 amp 115 volt pedestal. The sum of both legs can only be 30 amps and therefore only 30 amps flows in the neutral.

You cannot tie L1 and L2 together inside your TT while connected to a 50 amp 230 volt service. That would be a dead short at 230 volts. Wire would burn (well, maybe just a little smoke), breaker would trip. Your transfer switch prevents tying L1 to L2 when on shore power.

If this seems a little complicated, you are correct. If you can't understand, either I explained it poorly or you just don't get it. If you can't get it, please refrain from confusing others.

[ernest917]

Good grief...... My head hurts!!!!!

[Wayne M]

Originally Posted by MSHappyCampers

Are you saying that with a standard 50A hookup there are NOT two 50A circuits available providing 50 amps on each?

Yes there are, but each leg can only carry 50A. It doesn't equal 100A. If you look at the circuit breaker of mos CG's there is a bar across the wide 50 amp breaker which only connect the two toggles on the outside together. If one 50A leg trips the other will trip with it for safety reasons. nSome only have a single toggle for the wide 50A breaker and it trips both poles.

Originally Posted by rk911

then why am I able to pull 30+ amps on each leg?

Because each leg is capable of 50 amps. You are only drawing 30 amps per leg.

Originally Posted by TXiceman

The simple answer is the RV service is a 50 amp, 240 V, split phase. L1 or L2 to neutral you get 120 volts and L1 to L2 you get 240 volts.

The RV manufacturers, split the RV into two 120 volt circuits, each capable of drawing 50 amps or 12,000 Watts. Whether you multiply 240V x 50 Amps or 2 x 120 x 50, you still get 12,000 Watts.

Ken

Good reply.

Originally Posted by Mudfrog

[...]

So who's the wise guy that decided to use a different method of labeling 240 volt RV pedestals? Why do we call it 50 amp service when there's actually 100 amps available?

It's not 100A available, it is two 50A lines. If you tried to get 100A off of either line you would trip the breaker of one of the 50A legs and typically, through the circuitry, trip both breaker legs.

Originally Posted by ernest917

Good grief...... My head hurts!!!!!

I have to put it this way. When I plug in and everything works the way it is supposed to I know the electricity is good.

If I plug in and nothing works I know there is a problem. Then I have a headache.

[NXR]

Originally Posted by richard5933

It was my understanding that the 'A' in AC stood for alternating, as in alternating current. That means that the direction is constantly alternating.



Having L1 & L2 on opposite sides of the panel puts them 180 degrees out of phase. Looking at it on a graph, when L1 is climbing the curve L2 is dropping. They should never both be at the top of the curve at the same time. That's why the neutral line only has to carry 50 amps, not 100.

If you put an oscilloscope on the lines, the two ends of the transformer are 180 degrees apart waveform-wise. One "positive" when the other one is "negative". Or both zero with one going increasingly "positive" and one going increasingly "negative".

Current flow is current flow. The only time there is no current flow on the neutral is when both sides of the transformer are at the zero point and about to switch polarity.

Remember that 60 hertz used to be known as 60 cycles per second. One cycle is a full sine wave: Zero volts to peak positive, descending to zero volts and then to peak negative and back to zero is one cycle.

Ray

[WhiskeySierra]

Wow, I thought I had a grasp of basic electrical functioning, at least when I got my B-727 engineers ticket, decades ago. Reading this, and being new to RV’s and their respective systems is making me question myself. Stupid question, is there a basic resource (book) I can buy to bone up on specifically RV electrics? Since this seems to be the biggest system, with the most problems. Appreciate any help on this.

[Hit_the_Rhod]

So where is the Flux Capacitor?

[Bigd9]

Originally Posted by TeufelWolf

Wow, I thought I had a grasp of basic electrical functioning, at least when I got my B-727 engineers ticket, decades ago. Reading this, and being new to RV’s and their respective systems is making me question myself. Stupid question, is there a basic resource (book) I can buy to bone up on specifically RV electrics? Since this seems to be the biggest system, with the most problems. Appreciate any help on this.

Lots of information on the web, but I gotta tell you, forums like this one can teach you a LOT. You do have to filter out the misinformation to get to the actual facts, but then you need to do that in almost anything you do in life. Just be careful, even information in books can be flat out wrong.

Topics like this one generate a lot of responses, and lots of times people are saying the same thing, but in different ways, and even arguing with each other.

[NXR]

Originally Posted by TeufelWolf

... is there a basic resource (book) I can buy to bone up on specifically RV electrics?

It's a mess because each manufacturer can do their own thing.

As far as shore power is concerned the vast majority solely use plain old 120 VAC once the power gets inside, even if the pedestal outlet is 240 VAC.

If you have an onboard generator there also is an Automatic Transfer Switch to separate generator power from shore power. Some ATS units provide surge and other electrical protection functions, some don't. If not, you should provide something.

If you have an onboard generator it, as far as I know, always takes priority over shore power. So if the generator is running and you're plugged into shore power, the shore power is running nothing.

You may have an inverter or two to take 12 VDC and turn it into 120 VAC. You may have a separate inverter to power a residential refrigerator. You may have a pure sine wave inverter which closely duplicates normal house power or you may have another type that can cause electronics to have problems, modified sine wave.

You may have a Converter to turn 120 VAC into 12 VDC to charge batteries and run DC stuff. Mine provides 70 apps DC and keeps the batteries from overcharging.

And it gets worse when trying to figure out which circuit runs what and where the various breakers and fuses are located.

Air conditioners can use 12 VDC to light up the thermostats but need 120 VAC to run the compressor.

If you have more than one air conditioner you usually have a 50-amp coach. One A/C is on one leg of the 240 VAC circuit along with a bunch of other stuff and other A/C units are on the other circuit. But the onboard generator usually can run all of them.

Confused yet?

Ray

[Sbrownstein]

Originally Posted by TeufelWolf

Wow, I thought I had a grasp of basic electrical functioning, at least when I got my B-727 engineers ticket, decades ago. Reading this, and being new to RV’s and their respective systems is making me question myself. Stupid question, is there a basic resource (book) I can buy to bone up on specifically RV electrics? Since this seems to be the biggest system, with the most problems. Appreciate any help on this.

If you had a 727 engineers ticket, you shouldn't have that much of a problem. The biggest problem with RVs is that they have a DC system and an AC system and a bunch of systems that cross over between the two. First step is to find out what you have and often more important...where is it located in the RV? When compared to your previous life, all of this stuff is hidden and virtually automatic. Few switches or indicators. You have to be a bit of a sleuth to figure out what is on at a given time.

[Mudfrog]

Originally Posted by Mudfrog
[...]

So who's the wise guy that decided to use a different method of labeling 240 volt RV pedestals? Why do we call it 50 amp service when there's actually 100 amps available?

It's not 100A available, it is two 50A lines. If you tried to get 100A off of either line you would trip the breaker of one of the 50A legs and typically, through the circuitry, trip both breaker legs.

I sure don't want to cause more confusion or get anyone hurt. PLEASE,, correct me here if I still haven't got it straight.

Ok, after reading and doing a little surfing, I think I'm getting a hold of this now. I believe my earlier post above is wrong in that I don't believe there is a difference in the methodology used to label the different circuits.

The amp rating is stated for when 240 volts is used. 50 amps is the total amps that can be carried between H1 and H2 at an RV pedestal. With a neutral thrown in, we can get 120 volts and since the hots are 180 out of phase, this allows for 50 amps each leg without overloading the neutral wire. Gives us a total of 100 amps to use with our 120 volt RVs.

From what I have read this morning, residential 200 amps is the same. A total of 200 amps between 240 volt H1 and H2. For 120 volts, the capacity is 200 amps between H1/neutral and 200 amps between H2/neutral. This would be a total 400 amp capacity if only 120 volts were used.

p.s. OP, your BIG mistake was trying to explain electricity to your neighbors. As we can see in this thread,, confusion comes in quickly.

[Sbrownstein]

Agree totally. 50 amps at 240 is 12,000 watts. Two 50 amp circuits, one on each leg would be 50*120*2...or 12,000 watts. The service is specified at its highest voltage, just like a 100 or 200 amp 240 volt household installation...

[hoosierrun]

Originally Posted by Mudfrog

I sure don't want to cause more confusion or get anyone hurt. PLEASE,, correct me here if I still haven't got it straight.

Ok, after reading and doing a little surfing, I think I'm getting a hold of this now. I believe my earlier post above is wrong in that I don't believe there is a difference in the methodology used to label the different circuits.

The amp rating is stated for when 240 volts is used. 50 amps is the total amps that can be carried between H1 and H2 at an RV pedestal. With a neutral thrown in, we can get 120 volts and since the hots are 180 out of phase, this allows for 50 amps each leg without overloading the neutral wire. Gives us a total of 100 amps to use with our 120 volt RVs.

From what I have read this morning, residential 200 amps is the same. A total of 200 amps between 240 volt H1 and H2. For 120 volts, the capacity is 200 amps between H1/neutral and 200 amps between H2/neutral. This would be a total 400 amp capacity if only 120 volts were used.

p.s. OP, your BIG mistake was trying to explain electricity to your neighbors. As we can see in this thread,, confusion comes in quickly.

Although it has been explained in a few posts above, perhaps it would help to think of it as a moment in time. You never ever have 100 amps on a 50 amp circuit nor due you ever have 400 amps available on a residential service at any instant in time. It is alternating current so when 50 amps is measured on one leg, zero is measured on the other leg at exactly the same moment in time. 60 cycles per second means exactly that. Leg 1 is peak when leg 2 is zero. All your equipment in our RV or household is designed to run on AC if it is plugged into an outlet. It expects to see a peak and a null 60 times a second. Your meters, whether measuring current or voltage are actually measuring an average or RMS (root mean square - please don't ask me to explain that lol). Your meters can't distinguish between a peak and a zero, so even if it says (at max) you are drawing 50 amps off one leg and 50 amps off the other leg, it is just averaging those current flows over time. You need an oscilloscope to view these instants of time to see it. Never will there ever be 100 amps at any one period in time.

The campground manager or attendant really needs an electrician to review the CG's capacity. It was never designed for the RV loads to be simultaneously used.