7 sites on a Feeder in a RV park with a (Total of 35 sites in the park.) This feeder has 9600VA then 80ft 9600VA then 80 ft then 5 3600VA sites each 100 ft apart then 100ft to the breaker . Alum. wire.
9600-80' 9600-80' 3600-100' 3600-100' 3600-100' 3600-100' 3600-100'feeder brk 100'
Alum wire Question size of wire , Size of Feeder Breaker? Checking myself here.
Breaker to last site 680 feet.
Thanks Guys The Yooper
No one wants to take a Crack at this one????
Ernie- I don't understand the problem. Maybe you could word it a little differently and I'll take a crack at it. What are the actual loads at each site and how lond are the runs? Maybe it's just me but I can't follow you. Sorry.
I think the problem with RV parks is the load changes every time they rent a spot. When I was still looking at these with state they had times when all the spots were using an appreciable portion of the allotted 50a. They originally assumed 50% but that was not a good number on a hot night when these land yachts had both A/C units going full blast and every light, TV and other doodad on.
The size of the breakers is quickly determined by 551.73.
Figuring conductor sizes to compensate for voltage drop gets more complicated.
IMHO this is a time when I would figure voltage drop assuming 100% loading of the feeders.
I see where he is going now. The state was too dumb to actually adjust the size of the feeder as they went along.
This is something you could plug into an excel spread sheet and tune for load any way you want. Maybe Steve has something.
How did you get the loads? is the 3600 a 30a @ 120? That will change things a little. Putting the big loads at the end will cost you too. I am guessing 120v spots at 30a and 240v spots at 50a (using 40 for the load calc).
OK Yooper, here you go. If you start out with a 150a breaker the smallest wire will be 3/0 al. Use that for the first 80' hop from the end. You drop .8 volts. Then go 4/0, 4/0 4/0 for the next 80 and two 100' hops. That drops 1.2, 1.9v, and 2.2v respectively.
Then use 250MCM for the next two 100' hops dropping 2.1 and 1.7 respectivly. Run 350MCM back to the losd disconnect for another 1.9v.
I think that is 11.8v or just a shade under the 5%.
The 3600 watts comes out of the code book,see 551.73
Thats about what I came up with. I just wanted to make sure. The owner wanted the same size from start to finish so I went with 300 mcm in my Calcs.
Its hard to find rv eguipment that you can loop any thing larger than 250's thru so use 250 mcm with a full size nutral. I use 250/250/4/0 USE direct burial and use the 4/0 as the ground, reidentify with green tape and run a single 250 with the group for the nutral and reidentify with white tape.
I would just start out with a 200 amp breaker hit a terminal box.The runs are to long to just use one feeder. so break it up and run multipal feeders from the terminal box.you may have to run a feeder all the way to the farthest pedistal just because of voltage drop. I hope this helps.
John P
I use 250/250/4/0 USE direct burial and use the 4/0 as the ground, reidentify with green tape and run a single 250 with the group for the nutral and reidentify with white tape.
John that sounds like a possible 300.3(B) violation.
Bob the wires would be grouped together and in the same trench. This practice is quit common here for this purpose.The same as adding a #4alum use for a ground wire with 2/2/2 USE direct burial to feed a mobil home.
Do you use USE direct burial cable were you guys are at when I was in CT. I never saw it.
If this is a new RV park...
Reconsider the engineering towards medium voltages. (ie 4160)
Dry type XFMRs are available: 4160Y120 and can accept common mechanical lugs.
They are very commonly used for this type of situation.
Talk to the Poco about getting such a Service.
Good point Tesla. Some of the parks we did got the PoCo to feed the far end of existing runs with a new transformer so it split the load in half and allowed the existing wiring to work.
Bob the wires would be grouped together and in the same trench. This practice is quit common here for this purpose.
A lot of things are common practice and are still NEC violations.
IMO once one of your circuit conductors is a cable they all have to be in the cable.
Unless what you do can fit 300.3(B)(3) and 300.20(B) which is possible.
Do you use USE direct burial cable were you guys are at when I was in CT.
I have never worked with it.
Bob USE is not a cable with a jacket but three individual insulated wires and all you are doing is adding one more to it. You may also see it done to A over head service to add the third leg for a three phase service.
I dont see any violations of the code articles you sugjest may be violations.
I do like the idea of getting the pocco to place transformers thrue out the big mobile home parks. But like every thing else there is usualy a cost to it. Give the money to the Electrician or to the pocco and the electrian.Or just have the pocco feed every pedistal and give you a monthly meter charge for every service.
RV parks do not want utility metering, nor does the utility. The park owner prefers to do his own bookkeeping and make a handsome profit on the power they broker to the user. If the site is metered some states (like Florida) limit the amount of markup a park owner can assess above the utility rate but if it is unmetered they can set the flat rate at any price they want.
Greg I agree that the parks like to have there own meters, so thay dont have to pay the meter charges. I dont believe thay can charge more for the electricity then they pay in Mn. I dont know for sure though.
But I know that if the power company feeds the meters they are resposible for the cost of maintaining the wires in the ground and they may install the feeders for free if they get to charge for each meter.This may save the owner of the park alot of money for the electrical in the begining.that could be used to pay for meter charges for alot of years. and you would just pass the cost along to the lot rental anyway. Just a differant way to look at it.
I've held off on this thread, as it opens up all sorts of issues....
"RV Campgrounds" used to be places where folks lived a simple life, as they briefly traveled about on holiday. Many of the "campers" uses pop-up tent trailers, and the electric - at most - powered a light, a radio, and a small fridge. No more.
Today, these folks live in them 24/7/52. They drive these $$$$ rolling palaces, with every appliance known to man .... including hot tubs!
In this town, it is rare for anyone to ever leave these places. In short order, storage sheds pop up, small garages, you name it. Camping? Yea, sure.
Making matters worse, the "RV Crowd" has gotten pretty resourceful at playing with the electric.
The ones I've done I've done with separate feeders to each pedestal. Most pedestals tap the single receptacle off of the 240 circuit. The pedestal is, in fact, a small panel. Most of the DIY efforts seem to center on getting a second 120 volt circuit.
If I was able to design an RV park 'from scratch,' I'd probably want to treat it like a small sub-division .... large feeders buried 5 ft deep, Christie boxes, with taps off to meters at every pedestal. And I'd size each space's service like a residence ... wire for 100 amps (even if my actual breaker is 30 amps), and do residential-style load calculations.