Review my power layout

Hello I am looking at building on my property in Spartanburg County, SC. The property will have 3 buildings made from shipping containers, Main house(~1000sqft), Studio apt (360sqft), and storage building with computer room. The property will also have a RV parking spot will full power hookups.

The heat and cooling for the buildings will be mini spits hvac and the hot water will be tank-less LP.

The plan is to have a critical loads center what will be connected to generator and automatic transfer switch in the future. The whole goal of this layout is to have a single power meter.

Below is the layout. Will this work?Is the main power big enough?
https://docs.google.com/drawings/d/1...it?usp=sharing

 

You can only have one power feed to each structure.

 

Is there a way to use one generator for two building without powering the whole main panel?

 

Not without using advanced industrial-style controls on the panels. Far too expensive.

I don't see anything listed in the studio that couldn't be on the ATS if the whole panel was transfered to generator. The biggest loads are the stove and dryer which shouldn't be running if you aren't home anyway so they would be easy to turn off in an outage situation. It's actually nice to have the ability to use a range burner to heat up some dinner.

 

@CasualJoe
Do you have the NEC section number that talks about that?

I found 225.30(E) " Documented switching procedures. Additional supplies are permitted where documented safe switching procedures are established and maintained for disconnection "

With my above plan no circuit will have more than one source. The critical loads will be switched using a ATS to prevent backfeeding. If needed I can add a pull disconnect upstream to critical panel and normal panel for both the house and studio.

Also the plan is to have a fully bonded ground system with a ground in the 4 wire feeder cable and grounding rod for each building.







source NEC Rules on Outside Branch Circuits and Feeders

 

OR What about this

NEC 225.30(A) Allows for dual power feeders to a building for "Optional standby systems."

What about putting ATS in each building and running generator to each building. Then the ATS in the storage building where the generator would control when the generator starts and stops.

See link below for layout.

https://docs.google.com/drawings/d/1...it?usp=sharing

 

What's your budget for a generator and ATS?
Do you have natural gas?

 

All of the code sections are up to the interpretation of your local inspector, but generally my experience around generators that is that they are only willing to allow multiple feeders and switch/disconnect procedures when there are trained technicians or electricians on-site to operate the equipment. This would not be residential or multi-family buildings, but more like industrial sites, pumping stations, and so forth. These would be systems that are designed by an engineer and fully documented procedures that local staff is trained with.

Your local power company will also have standby generator standards that you'll need to comply with in addition to the NEC. These usually focus on the backfeed protection aspect, and sometimes and exterior isolation, disconnect that a lineman can access.

 

@Electromen

I was hoping to stay around $5k for gens and transfer switches.

I do not have natural gas only LP.

 

Look at these generators, both are LP/NG. They're rated for service entrance which means the ATS would be your main breaker. All panels after this would be four wire sub panels including your 200 panel. You can add about another $600 in material to set it up.
LOOK HERE Gerard 22KW

HERE"S a Brigg's & Stratton 20KW
Briggs is a little easier to set up. The ATS is a simpler design.

One thing about generators, the ATS much match the generator. It would be best to buy both at the same time.

The Brigg's has a simple load shedding ability. If you get near the full capacity of the generator, it's possible to install devices that would shut down certain items like a dryer while others run like hot water and vice versa. An example would be three A/C units the load shedding would alternate the A/C units depending on demand.
The load sheding remote modules can be added later the are at the bottom of the page

 

@Electromen
The brigges with the remote cut off modules is a great suggestion, thank you. That will allow me to run less wire and reduce the complexity of the layout. After read the docs the system will support upto 8 remote cut off modules which is more than enough for me.

Question: Base on the below laoyut is the panel sizing right?
200amp in the storage building with the service entrance and generator?
100amp panels in both the sudio apt and main house?


https://docs.google.com/drawings/d/1...it?usp=sharing

 

Is this overhead or underground?

I think your pushing the limits of the 200 amp service. The possibility of two stoves, two dryers, two AC/Heat plus the RV all running at the same time is remote but it's possible. You should always allow for expansion like a hot tub.

You can install a 320 amp meter socket and feed two-200 amp main breakers.
To do this you would use two 200 amp - 4/0 entrance cables. In other words, two entrance cables from the meter socket. Use dual 4/0 lugs in the mater socket.
Briggs is the only manufacturer that I know of that makes an ATS for this purpose. LOOK HERE

The ATS would be your main breakers. It has two - 200 amp main breakers.
One 200 amp Main could feed a 200 amp panel in the Storage Building and also feed the Studio. The second Main can go directly to the main house.

 

A simple layout would look like this.
Cable from meter to ATS would be 4/0 SER
All other panels would be 4 wire sub panels.
Water line Ground would be #2 copper and go to ATS
Ground rods would go to ATS

 

One thing you must pay attention to here in particular is that these buildings are not permanent structures and can be moved such as in the case of a mobile home can be . Thus the need for the power to go to a location that is not directly attached to the building/container itself but to for example a pole where the meter will be and then to the container. This may hold true to the other two structures. Before you go installing the panels find out where they MUST be installed and how. This could be a very costly mistake if done incorrectly and you will fail inspection from the start.

 

@AFJES

Good catch, yes all buildings will be built on 8 in poured concrete piers with a metal top plate. The top plate will have welded j hooks placed into wet concrete. The shipping container will then be welded to the top plates.

 

zunder1990, ok, good. Glad that is taken care of. Simple thing to overlook.