Temp Power to 40 RVs

starrpamph

Member
Location
Kentucky
Occupation
Entertainment Electrician
I work on an annual event where we power 50 or so large RVs for a week from a couple towable diesel generators. All 3 phase 120/208 generators and distribution and 50 amp 4 wire connections for the RVs. I have never seen one of these rigs with any L-L loads.
I am powering an event that is a bit out of my wheelhouse for a new music festival. Client wants me to supply temp power to 40 RV's.. Most will be 50A some 30A. I have the 208v distribution, feeder and adapters in stock, but not sure what size generators to supply him. I was thinking about bringing two 400kva but I can't imagine those RV's using that much power consistently. Any insight on what size units you guys use for your event? Any idea what your average hot summertime current draw is on each leg?
 
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wbdvt

Senior Member
Location
Rutland, VT, USA
Occupation
Electrical Engineer, PE
Some RV's have 2 air conditioners (15A each), residential refrigerators, several TV, microwave, washer/dryer and even a dishwasher so to be conservative, figure at least 40A per RV.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector
400 kva would be in-line with the "required" supply but as you noted it might be a little light for a summertime draw.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
If this were an RV camp, NEC would only require a 197 kVA service for 40 campsites with 50A 120/240V receptacles each.


With that said I have no direct experience with this. The NEC is known to be rather conservative with service sizing (making them much larger than necessary) but a utility service would have transient overload capability that a generator probably doesn't have.

-Jon
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
If this were an RV camp, NEC would only require a 197 kVA service for 40 campsites with 50A 120/240V receptacles each.


With that said I have no direct experience with this. The NEC is known to be rather conservative with service sizing (making them much larger than necessary) but a utility service would have transient overload capability that a generator probably doesn't have.

-Jon
As Winnie says, especially now that the 50 amp RV calculation are 12000VA each that used to be 9600VA
The NEC is conservative. At 40 campers the demand factor is 41%
12000VA x 40 campers = 480,000 VA
480,000 x 41% = 196,800VA (197KVA)
So just for safety sake you double this. One 400KVA generator should suffice but you may be better to use a single phase 120/240 volt. Since I,ve done few campgrounds for fair events these type of events kinda push things over the minimal limits of NEC because of added “party” necessities utilized ( extra beer refrigerators, crock pots, etc ) when nearly all sites are being occupied unlike actual campgrounds.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
Most RV’s utilize 120 volts only, even on the 50 amp plugs, so 208 shouldn’t be an issue, as all loads will be phase to neutral.
 

starrpamph

Member
Location
Kentucky
Occupation
Entertainment Electrician
As Winnie says, especially now that the 50 amp RV calculation are 12000VA each that used to be 9600VA
The NEC is conservative. At 40 campers the demand factor is 41%
12000VA x 40 campers = 480,000 VA
480,000 x 41% = 196,800VA (197KVA)
So just for safety sake you double this. One 400KVA generator should suffice but you may be better to use a single phase 120/240 volt. Since I,ve done few campgrounds for fair events these type of events kinda push things over the minimal limits of NEC because of added “party” necessities utilized ( extra beer refrigerators, crock pots, etc ) when nearly all sites are being occupied unlike actual campgrounds.
Thanks for the insight. I might give him two 300KVA and split it up into 2 separate systems of 20 each with a bond between the two machines. The larger generators also come with larger fuel tanks which is nice to have.
 

mopowr steve

Senior Member
Location
NW Ohio
Occupation
Electrical contractor
Thanks for the insight. I might give him two 300KVA and split it up into 2 separate systems of 20 each with a bond between the two machines. The larger generators also come with larger fuel tanks which is nice to have.
300’s should be plenty.
One of our campground sections (about 40 sites) at fairgrounds is about 15 years old. During fair on a 90* day it runs about 10% higher than NEC calculations due to the added refers and such. That is an older section with primarily 30amp recepts. Our latest addition of 30 sites (all with 50amp recepts) had a demand load of 46kw but we probably only have 10% of campers utilizing a 50 amp at this point in time out of the 230 total sites currently.
This may give you food for thought.
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
I am powering an event that is a bit out of my wheelhouse for a new music festival. Client wants me to supply temp power to 40 RV's.. Most will be 50A some 30A. I have the 208v distribution, feeder and adapters in stock, but not sure what size generators to supply him. I was thinking about bringing two 400kva but I can't imagine those RV's using that much power consistently. Any insight on what size units you guys use for your event? Any idea what your average hot summertime current draw is on each leg?
Usually, music festivals or RV Conventions are planned in advance. The last RV Owners’ Convention I attended -- involved around 7000 RVs that was held in Arizona at the Arizona Raceway at Goodyear.
RV owners had to register months and almost a year to buy ticket for the event.

The contractor had several portable generators all over the site. The contractor even had to provide portable street lights too.

The prospective attendees have to register and inform management what size RV they have.
This information is the basis for sizing the generator needed to power the whole event.

Have you been to “BURNING MAN” event in Reno?

This event is like a city that rises overnight with hundreds of “HIPPIE”-like attendees that have with them luxurious RVs , Camper Tents, and Trailers . . . even Europeans wait “in line”-- and they come and pay around $3000 to attend this event.

My wife didn’t like it so, that was the end for us.

The interesting part is every attendee is required to pick up every bit of trash you leave behind after the event.
Most RVs are either 30 Amp powered units or 50 Amp units.

You’ll never know what size RVs until they show up.
 
Also consider whether this is really just RVs (for people to camp) or also includes portable office trailers or food trucks- both of those could easily have L-L loads. And I wouldn't even consider doing this with a single-phase, all of the rental equipment is going to be 3-phase; just go with that.

BTW, Burning Man isn't in Reno, it's more like 100 miles north of Reno.
 

Todd0x1

Senior Member
Location
CA
I am powering an event that is a bit out of my wheelhouse for a new music festival. Client wants me to supply temp power to 40 RV's.. Most will be 50A some 30A. I have the 208v distribution, feeder and adapters in stock, but not sure what size generators to supply him. I was thinking about bringing two 400kva but I can't imagine those RV's using that much power consistently. Any insight on what size units you guys use for your event? Any idea what your average hot summertime current draw is on each leg?
The one I do is in the middle of winter so I have the luxury of not having to deal with the AC load. Each RV on that one gets a 30 amp circuit (even though most of the rigs have 50 amp connections), except for a few where they pay for 50A circuits, and generator is sized to be able to supply all circuits at full load. I don't recall exact numbers, but I remember average load being relatively low but peak loads being close to capacity at times.

That's the problem with powering RVs you never really know what their draw is going to be and you can't depend on load diversity. During the summer you can pretty much count on those AC units being left on all the time. If you have the big generators, I would bring them to be safe. If not, I would multiply (number of RVs) * (AC load considering 2 AC on each + 20 amps per RV)

No one will remember that the generators were oversized, but they will never forget that they lost power.

Edit: I did send a small 40kva unit to burningman in 2019 to power 3 big RVs and some general use power and they were having to fuel it every day which means that unit was close to max load.
 

Todd0x1

Senior Member
Location
CA
300’s should be plenty.
One of our campground sections (about 40 sites) at fairgrounds is about 15 years old. During fair on a 90* day it runs about 10% higher than NEC calculations due to the added refers and such. That is an older section with primarily 30amp recepts. Our latest addition of 30 sites (all with 50amp recepts) had a demand load of 46kw but we probably only have 10% of campers utilizing a 50 amp at this point in time out of the 230 total sites currently.
This may give you food for thought.

The difference with normal camping VS festival type use is people typically leave their AC running all the time even when theyre not in the RV, and you dont get much in the way of people staggering their schedules. They all get up at the same time and make coffee, etc.
 

Todd0x1

Senior Member
Location
CA
The other thing I noticed was everyone showing up with dead batteries so as soon as they plugged in there was quite a bit of current draw from the battery chargers.
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
No one will remember that the generators were oversized, but they will never forget that they lost power.

Edit: I did send a small 40kva unit to burningman in 2019 to power 3 big RVs and some general use power and they were having to fuel it every day which means that unit was close to max load.
When we were there I brought and extra can of gas but I couldn't store a lot because of safety reason.

My generator handled the 100 deg heat very nicely. I used my solar array with inverter to charge my battery bank.
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
Never been to middle--of- winter music festival.
Must be interesting-- singing Christmas carols instead of blaring HEAVY Metal over a loud sound system. :)
 

Todd0x1

Senior Member
Location
CA
When we were there I brought and extra can of gas but I couldn't store a lot because of safety reason.

My generator handled the 100 deg heat very nicely. I used my solar array with inverter to charge my battery bank.
I fortunately wasn't there. Customer took the equipment up themselves. Gave them the generator, cables and adapters, and a truck with a 100 gal diesel transfer tank to tow it with and transport fuel. They ran 24/7 for the entire event. A year and change later and I am still trying to get all the dust out of that generator.
 

kwired

Electron manager
Location
NE Nebraska
If this were an RV camp, NEC would only require a 197 kVA service for 40 campsites with 50A 120/240V receptacles each.


With that said I have no direct experience with this. The NEC is known to be rather conservative with service sizing (making them much larger than necessary) but a utility service would have transient overload capability that a generator probably doesn't have.

-Jon
That would be my concern. I've connected smaller sites with 400 amp single phase supply, but POCO only uses a 37.5 or 50 KVA transformer. One at a county fairground where they will plug more than one RV into a pedestal and actual number of RV's ends up exceeding what you used to design the system.
 

myspark

Senior Member
Location
SCV Ca, USA
Occupation
Retired EE
I fortunately wasn't there. Customer took the equipment up themselves. Gave them the generator, cables and adapters, and a truck with a 100 gal diesel transfer tank to tow it with and transport fuel. They ran 24/7 for the entire event. A year and change later and I am still trying to get all the dust out of that generator.
That is the biggest concern by RV rental unit outlets because renters don't take care of the gensets. They thought that you just start the unit and keep adding fuel when they (gensets) ran out of gas.

RV Rental outlets require a deposit to cover expenses in case the genset requires repair when returned.
Generators are prone to damage when operated in dusty environment. It really needs replacement of filter every so many hours of operation.

The sand dust in the desert will choke everyone--almost.

This deposit is required when you attend the BURNING MAN.
 
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