RV PARk Service Sizing

[220wire]

I am looking at an RV park with 21 sites on it and need help checking my calcs. The customer wants all sites to have 50a 250/125v at each site. I come up with 378a of load. Utility will be single phase 120/240 sevice. Can I get away with installing a 400a service? The temprature here is usually temperate enough to never need Air conditioning. Maybe just a small space heater. Most of the sites will be occupied by trailers not big Diesel pushers. If the cust. ever wanted to expand to other sites it would be near impossible with voltage drop taken into consideration. It would be cheaper to have the POCO drop a new service down the road, to save on the super sized conductors. I am just a bit fuzzy on loading a 400a service to near its maximum capacity (not that it will ever happen). This is really one of those jobs I feel that looks worse on paper than it actually will be.

21 sites x 9600va = 201,600va
201,600va x 45% demand factor = 90,720
90,720va / 240v = 378a

Any help or suggestions would be greatly appreciated.

 

[steve66]

If it's one vehicle per site, it looks like you have the load calcs. right.

If I were engineering that project, I would probably spec. the 400A service also. I also think it will be rare (if ever) for the load to hit the calculated value.

If they add more sites in the future, that's up to them to increase the service as necessary.

 

[beanland]

POCO Service Allowed

POCO Service Allowed

You also need to make sure the POCO will provide a 400A single-phase service. Some POCO want you to go to 208Y/120V at or above 400A.

Calculations look correct.

Voltage drop is a problem. With 30 feet between spaces, if the spaces are in a single row, that is 630 feet. Voltage drop, if fed form one end, will be a killer.

You need to look at the layout and service point and try several configurations to find one that has acceptable voltage drop at reasonable cost. I suggest that you may want 4-5 100A OCPD in a panel and 100A branch circuits, each which feeds 4-5 50A pedestals.

You may need to move the service point. It is always better to have the service point and meter central rather than in one corner of the park.

 

[Electron_Sam78]

why 4-5 sites per 100 amp CB? Isn't it a demand factor of 65% with 5 sites per table 551.73? That would make 5 sites 130 amps. Do you apply the total demand factor (21 sites) to the branch circuit calcs for 5 sites which would make it 90 amps? I've never done this before but am going to in the near future.