50 Amp wiring

so people here are trying to tell me that 50 amp service is only 20 amps more than 30 amp service, and not 70 amps more? that certainly isn't what posts have said over the years. and I don't see why the fact that the neutral balances out to zero really affects this situation, other than size needed of the neutral wire.
bumpy

roscott wrote:
I just bought a house that has an RV pad. Unfortunately, it is wired for 30 amp service. I need to get an electrician out to convert to 50 amp to support my rig. My question is whether a licensed electrician will know exactly what to do for the conversion or is there something I need to specifically mention? Or, I may just have him run another dedicated 50 amp line since my panel will support it...but need to now what, if anything, to tell him. This is my first 50 amp unit so I'm no expert as to specific electrical needs for the rig. Any help is appreciated. Sorry if this is redundant. I could not find my specific need in a search.

I'd leave the 30 intact, since it's doubtful that it's four wire and large enough anyway, so probably more labor involved. As for the 50amp and even if this electrician isn't familiar with RV's, he only has to know how to wire it like a residential electric range. The trouble sometimes starts with the unknowing when wiring for a 30amp coach. Fact is, no one should install a 30amp service when starting from scratch and might save on an upgrade later on.

If the OP shows the electrician the Diagrams provided and maybe the plug on the RV if it is avaiable, he should be in good shape.

wa8yxm wrote:

dougrainer wrote:

The point being is, There is NO REASON to use any part of the legs on 50 amp RV service other than to supply 2 out of phase 120 legs to the Circuit panel. 220 and 240 have no bearing to the OP.

MANY, and I mean MANY 50 amp RV's do, in fact, use the fact that 50 amp service is 50 amps at 240 volt to their advantage, in fact ALL 50 amp RV's do but that is a different reason.

The MANY: IF you have an energy management system that detects 30 or 50 amps and controls how much power you use by turning say an air conditioner off to keep it below 30. THE computer in that device checks for 240 volts (Actually likely more than 200) leg to leg, if the leg to leg is zero, it assumes 30 amps.

Second. I think it was you who said 50+50 = 100.. True in math class, but as I said in electricity things change.. 50+50 = zero,, Yup ZERO amps on the neutral leg (the common leg) if both sides are perfectly balanced, it's 50 amps moving through the two legs, but you do not add 50+50 to get 100.. Rather you use each amp twice and it remains 50... Now,,,, If you need me to shoot you with a water cannon to explain it.. Can do.

Imagine this

You have a water gun, pumping 50 GPM at a target, the water that hits the target is collected and pumped toward another target (Actually back to the original source) How many gallons per minute flows.. 50

How fast does the source tank run down,, remains the same (Since every gallon pumped out is returned).

The source tank is the neutral, the two cannon, the legs.

Yep. And earlier I believe it was stated if an electricain calls it 240 volts - Don't hire him.

Well the problem is, it IS a 240 volt circuit and that is in fact what it needs to be. Exactly for the reason pointed out. If you don't have 240 volt, your neutral can be called upon to carry TWICE its rated amperage - with NO protection.

dougrainer wrote:

The point being is, There is NO REASON to use any part of the legs on 50 amp RV service other than to supply 2 out of phase 120 legs to the Circuit panel. 220 and 240 have no bearing to the OP.

MANY, and I mean MANY 50 amp RV's do, in fact, use the fact that 50 amp service is 50 amps at 240 volt to their advantage, in fact ALL 50 amp RV's do but that is a different reason.

The MANY: IF you have an energy management system that detects 30 or 50 amps and controls how much power you use by turning say an air conditioner off to keep it below 30. THE computer in that device checks for 240 volts (Actually likely more than 200) leg to leg, if the leg to leg is zero, it assumes 30 amps.

Second. I think it was you who said 50+50 = 100.. True in math class, but as I said in electricity things change.. 50+50 = zero,, Yup ZERO amps on the neutral leg (the common leg) if both sides are perfectly balanced, it's 50 amps moving through the two legs, but you do not add 50+50 to get 100.. Rather you use each amp twice and it remains 50... Now,,,, If you need me to shoot you with a water cannon to explain it.. Can do.

Imagine this

You have a water gun, pumping 50 GPM at a target, the water that hits the target is collected and pumped toward another target (Actually back to the original source) How many gallons per minute flows.. 50

How fast does the source tank run down,, remains the same (Since every gallon pumped out is returned).

The source tank is the neutral, the two cannon, the legs.

Bumpyroad wrote:

B's Bunch wrote:

Bumpyroad wrote:

B's Bunch wrote:
I have to question your thoughts on this considering all of your experience. A 50 amp service is just that 50 amps. Argue this as I am sure you will. Larry

gee, and I always thought that 50 amp service to RVs used two 50 amp breakers
bumpy

and neither will allow more than 50 amps current to pass

in the last math class I took, I would swear they said that 50 plus 50 equals 100.
bumpy

You are delivering 220 volts to the receptacle at 50 amps. When it is split by the coach, then you have 100amps aggregate. That's why they call it 50amp service, not 100. If you were to drop the voltage to 60 volts for some reason, you would have 200amps at 60 volts (assuming no loss from the transformer). But once again, the RECEPTICLE is 220v at 50amps just like the 220v coming into your house from the power company, math class or not.

Heisenberg wrote:

I made a mistake typing in the numbers. I should have typed 6/3 with ground. #6 copper is worth 55 amps.

But, you could drop one size for the ground...so technically you were only 3/4ths wrong.....:B.....Dennis

2oldman wrote:
50a threads get almost as good as Walmart threads. I answered this with no BS on the first page.

Already printed out the diagrams 2oldman. Thank you

dougrainer wrote:

Gau 8 wrote:

dougrainer wrote:
As a fellow Texan, Licensed in Texas does NOT mean anything when involving Electricians. Just ask him a simple question.
Is a 50 amp RV service 220 volts? If he answers YES, then do not hire him. . Doug

A 50 amp service has 220 available if it is needed. All depends on how you use the legs. But you know that.

Eddie

The point being is, There is NO REASON to use any part of the legs on 50 amp RV service other than to supply 2 out of phase 120 legs to the Circuit panel. 220 and 240 have no bearing to the OP. You state 220/240 and people get confused. Technically, you are correct, but in layman's terms you confuse people. Doug

Have you ever admitted being wrong? The point is that there is 220 available. Some high end coaches use it. Cant help it if the truth is confusing. There is 220 available just like in your house.

Eddie

Bumpyroad wrote:

B's Bunch wrote:

Bumpyroad wrote:

B's Bunch wrote:
I have to question your thoughts on this considering all of your experience. A 50 amp service is just that 50 amps. Argue this as I am sure you will. Larry

gee, and I always thought that 50 amp service to RVs used two 50 amp breakers
bumpy

and neither will allow more than 50 amps current to pass

in the last math class I took, I would swear they said that 50 plus 50 equals 100.
bumpy

In math you are right,, But in electricity some of the descriptions change, SO it is 50 amp 120/240 volt service.. .. I will tell you the danger of your thinking.

Some people have reported they plug into a park and the Energery Manager in the RV shows 30 amps. even though it is clearly a 50 amp socket.

Well, upon inspection with proper test gear they find that the two hot legs are in parallel (Side to side voltage is ZERO, side to top is 120 on both sides but side to side is zero)

THIS .. Means that if you are pulling max power (100 amps at 120 volts) the NEUTRAL wire is hauling twice the load it was designed for.

And that is how the fire started.

If you understand that it is 50 amps at 240 volts divided then you wire it right, and the neutral under those exact same conditions (Max power) is carrying... Not a thing, it is just sitting there, idle, NO FIRE.