Maxing out 200 Amp Main?

[JRI]

Originally Posted by Talloaks

I picked out a few phrases from your post to illustrate the basis for my suggestion to you: why not wire it in accordance with code? Why not give your AHJ a call to become familiar with local requirements? The NEC provides you the answers to your questions in terms of utilization factors to apply for multiple connections to a campground electrical circuit.

Kudos to you for asking good questions. Unfortunately, the use of what seems like common sense combined with a minimal understanding of how electricity works, compounded by uninformed but confident advice from somebody on an online forum, leads to expensive equipment damage and possible injury, not to mention disappointment and bewilderment. Good luck.

When I got to this reply I stopped reading. This reply is so well written, and the point so well made, I needed to go no further. Great job Talloaks

[pobstlmo]

Personally:
I would install 4 Fifty amp breakers.
If it goes over a breaker will trip.
Second a 30 amp can run off of a 50 amp
Remember the rv has a breaker at 30 amp.
You could have a 50 split into two 30 to power two rv’s
Again too much a breaker trips.
Why limit your self. Or the number of friends.

Water, sewer, tv and internet, don’t forget about those too.
As a RV park you will also need trash pickup, pool dog park and a campfire.

what’s your address? I want to make a reservation.

[Franey]

Originally Posted by KenZ71

Slightly puzzled here... and probably thinking too much

So my property had a mobile home on a separate meter, I've repurposed that cement pad and meter for my Class A.

The panel has a 200 Amp main GE THQMV2200 so does that mean my max load would be 4 friends with 50 Amp RVs blasting AC?

Simple math 4 x 50 = 200. Or does it?

It is often said a 50 Amp double pole can provide 50 Amps on each leg. Most I've seen on the PowerWatchdog app is 30 to 35 on each leg. And that would be all RV ac units on at the same time.

Using the logic a 50 Amp double pole can provide max 50 per leg does that mean a 200 Amp main is also providing 200 max per leg or 800 total?

Since 4 rv's would probably not be loaded to the max, you world be ok. Each one would probably only be drawing half that, 25-30 amps.

There is no 220 in an RV. What you have is a 220 circuit split between two hot wires and a neutral, or two 115 volt circuits. Since it is single phase, and if the load is balanced between the two hot wires, the current flow between the two hot wires in series. This is why the breaker is 50 amps on each pole. The breaker is to protect the bus. The individuals smaller breakers protect the wiring connected to them.

If the panel is a 200 amp breaker, that breaker protects that bus. If that bus gets more than 200 prolonged amps, it will trip.

You should/ will be ok as long as nothing else, or very little, is working on the 200 amp panel. Off a beaver triple, just shed load on the rv's.

[TXduo]

As a total FWIW side story: about two weeks ago I was at an older RV park (Canadian) that as I recall. had 9 50 Amp and 7 30 Amp sites fed from a old 200 amp double pole main feed. I'm guessing they "upgraded" 9 old 30 amp sites to 50 amps for "marketing purposes". That main 200 amp breaker tripped very often and park management told people to run no more than 1 AC and shut that off to run your microwave. leave your fridge and hot water on propane.... They did however advertise these as "50 amp" sites. I'm guessing the old configuration was 8 + 8 30 amp sites on each old leg which at 80% use would typically run all 16 sites. But people desired 50 amp sites so I guess this is the mess the park came up with. Even if everyone tried to manage themselves to a typical 30 amp usage, who knows for sure which leg any particular 50 amp coach would pull from so could easily have 9, 10, 11 or more effectively pulling from one leg causing a very unbalanced load scenario. When I questioned the park management about this electrical setup they said the utility wouldn't upgrade the service to the main 200 amp breaker nor add another service line for another 200 amp breaker. Seems like a crazy setup to me. BTW, the park voltage was often 108-110 volts, sometimes dropping below that and tripping off surge protectors that check for low voltage conditions. The park also said run your generator if you want too. I'm NOT suggesting this was a great configuration, just what you sometime stumble across in the field.

[rvharry]

Most camp sites are set up on 20/30/50 pedestal, are typically fed with 70 amp breaker, the panel board is normally a 225 amp feeding seven (7) pedestals which based on NEC (Nat'l. Electrical Code) would be correct at 7 site at 28% demand = 196 amps which is pushing 80% maximum on panelboard per NEC. Because of actual demand is much lower. Look at your house panel board, you will see your breakers added up far exceed panel size. See NEC Table 550.31 for campsite demands. In your case 4 sites carry a 39% demand factor. I would supply each pedestal with 70 breaker minimum. based on 70 amp at NEC demand factor = 105.60 amps.

[Mikeytheb]

With all the responses here - why has no one pointed out that RV wiring is different from house (mobile home) wiring. Dozens of posts on the forum addressing this. Please make sure you re-wire to support RVs - otherwise nothing is going to run.

[greeneville1]

Hi Folks, A very good reference for the sizing of electrical services for RV Parks are found in Table 551.7A of the National Electrical Code. As the number of RV sites are increased in the table, the demand factor allows a certain percentage decrease in main service size . Their way of thinking was the chances all rv sites drawing 100% load is less and less as the number of sites increase. We are a commercial and industrial electrical contractor in East Central Florida and do install new RV parks and service quite a few. We can tell you from experience that these tables sometimes do not work well in southern climates with medium and big rigs using the majority of sites. We always recommend to engineers designing new parks or additional sites to increase service sizes by 10 to 20 % over Table 551.7A figures. Most up scale coaches have load management systems that try to limit load to around 80% of 50 amp. Some older coaches don`t have this system . At my own home, I have (9)-50 amp sites with the load being split between our 300a service at the house and a separate 200 amp service at the barn . Never had all 9 going at one time but have had 6 big rigs in summer heat without problems. Stay Safe

[shootist]

Originally Posted by greeneville1

Hi Folks, A very good reference for the sizing of electrical services for RV Parks are found in Table 551.7A of the National Electrical Code. As the number of RV sites are increased in the table, the demand factor allows a certain percentage decrease in main service size . Their way of thinking was the chances all rv sites drawing 100% load is less and less as the number of sites increase. We are a commercial and industrial electrical contractor in East Central Florida and do install new RV parks and service quite a few. We can tell you from experience that these tables sometimes do not work well in southern climates with medium and big rigs using the majority of sites. We always recommend to engineers designing new parks or additional sites to increase service sizes by 10 to 20 % over Table 551.7A figures. Most up scale coaches have load management systems that try to limit load to around 80% of 50 amp. Some older coaches don`t have this system . At my own home, I have (9)-50 amp sites with the load being split between our 300a service at the house and a separate 200 amp service at the barn . Never had all 9 going at one time but have had 6 big rigs in summer heat without problems. Stay Safe

Thankyou for taking your time to post this. It's a blessing to get information from an experienced pro.

[Bigceasar]

Originally Posted by rvharry

Most camp sites are set up on 20/30/50 pedestal, are typically fed with 70 amp breaker, the panel board is normally a 225 amp feeding seven (7) pedestals which based on NEC (Nat'l. Electrical Code) would be correct at 7 site at 28% demand = 196 amps which is pushing 80% maximum on panelboard per NEC. Because of actual demand is much lower. Look at your house panel board, you will see your breakers added up far exceed panel size. See NEC Table 550.31 for campsite demands. In your case 4 sites carry a 39% demand factor. I would supply each pedestal with 70 breaker minimum. based on 70 amp at NEC demand factor = 105.60 amps.

I had over 200 50 amp sites and never had a 70 amp breaker. In fact I don’t think I have ever seen one . I’ve also never seen or heard of a 225 amp service. We almost exclusively had 200 amp services with the only exception being a 350 amp service that fed my personal residence and a 7 site loop of 50 amp services. Never did any of those service mains trip, save for the one time a wayward RV drove over one like they were scoring points in a video game.

[greeneville1]

Curious-Was your large RV Park located in the deep South. Also, a 70amp 2pole breaker is a common size breaker even though we don`t see many of them in a RV Park service. A 225amp single phase or 3 phase 4 wire service is one of the most common size services in a commercial or industrial application. Stay Safe.

[Mudfrog]

This really shouldn't be that difficult.

I used to have a mobile home. The outside panel was mounted on a pole just below the meter. It contained the 200 amp main breaker and capacity for 8 breakers below that. If the OP's is similar, then four 220 volt 50 amp breakers can be installed. Come out of the bottom of the box with PVC conduit and proper sized wiring (2 hots, neutral, ground), buried the appropriate depth in the ground, out to the location of the pedestal.

There are nec guidelines for all of the above so be sure to look them up before installation. For examples, wire size, conduit burial depth, pedestal box's height above ground, etc,,,. And of course, depending on where you're located, you might need to obtain a permit, have inspected by the city, and/or be required to use a licensed electrician.

[greeneville1]

Sir , we are hiring. Stay Safe.

[Franey]

Originally Posted by Mikeytheb

With all the responses here - why has no one pointed out that RV wiring is different from house (mobile home) wiring. Dozens of posts on the forum addressing this. Please make sure you re-wire to support RVs - otherwise nothing is going to run.

It was mentioned.

[Bazou7101]

I would venture to say that 4 friends running their ACs is inaccurate because a motor usually takes 3 times the amperage on start up.