Small Shed Electrical Design

[EBSoares]

Hi, all.
One of our high school projects has a small shed near the main building (separate building). The shed will have a motorized rollup overhead door (208V, 3ph), a couple of light fixtures (277V, but could be 120V if needed), and receptacles (120V) - for a total of 3 circuits. All the voltages required are available in the main building.
I was hoping someone might be able to help me with the following questions:

1. Does the shed need its own separate grounding system (with a ground rod, ground bar, and all that) as per 250.32(A), or does the exception there apply, if we simply provide the three circuits from a panel at the main building?
2. Does the shed need its own panel as well? It feels like overkill to provide a panel for just a shed.
3. If a panel is not required and we can simply provide 3 individual circuits, does 225.31 apply, requiring that each each circuit have its own disconnect?
4. Do you have any important tips for the electrical design of sheds?

Thanks in advance.
Edgar

 

[infinity]

If you only need 3 circuits you could run a single MWBC to the shed. By doing so you would not need a GES.

 

[don_resqcapt19]

Based on the loads, I think you need a feeder and a panel in the building and that will trigger a requirement for a grounding electrode system.

The only way around this would be to use a single 208Y/120 volt circuit to feed all of the loads. That would mean there are no separate overcurrent protective devices for the various circuits in the shed.

Not sure that is possible without knowing the actual loads.
The use of 277 for the lighting would complicate the installation a lot.

 

[Joethemechanic]

Based on the loads, I think you need a feeder and a panel in the building and that will trigger a requirement for a grounding electrode system.

The only way around this would be to use a single 208Y/120 volt circuit to feed all of the loads. That would mean there are no separate overcurrent protective devices for the various circuits in the shed.

Not sure that is possible without knowing the actual loads.
The use of 277 for the lighting would complicate the installation a lot.

Yeah, I'm not seeing the use of two unrelated voltages, now you have two feeders or a transformer in the shed

 

[suemarkp]

If the roll up door was 480V, you could run a 480v and 208/120 branch circuit to the building. The only time you can have multiple branch circuits to a building is when they have different characteristics, such as differing voltages.

Running a feeder instead of a branch circuit pushes you to a ground electrode system.