Running electric out to my shed

I want some advice as to the best way to do this project.I do have experience with indoor electrical. The attached picture is the breaker box on the back of my house, the other is the breaker box in my house.The one on the back of my house runs power to the well pump, the a/c, and the septic pump. There are 2 spots to add to, and i want to run power to my shed about 150 feet away. I just want a light, and 2 outlets in the shed. If possible, i want to run 1 outlet to my front gate, about 250 feet away to eventually have an automatic gate opener. What is the best way to run this? UF cable in PVC conduit, 10-2 wire, or 12-2 wire, and what size breakers? I have 2 spots to add breakers. I appreciate any help as i know this is a big project, and want to do it the best way!
Thank you in advance!! Other info.....I live in Charlotte, NC. if that info is needed.

 

Here is a diagram of the layout.

 

Best practice is to not run cable in conduit except for shot sections of conduit to protect the cable where it enters and leaves the ground. If you use conduit use individual conductors such as THWN.

I would suggest a multi wire 120 volt circuit to the shed using #10. That would give you two 20 amp 120 circuits to the shed. One for the shed one to continue on to the gate. I suggest # 10 because of the distance. Breaker at the supply panel would be either a 20 amp two pole breaker or two handle tied single pole breakers.

The above assumes the gate opener is 12 volts powered by a battery and the 120 is only for the charger. A 120 volt gate opener would probably require larger wire. Assuming the gate opener is 12v as most are a solar charger may be cheaper and easier. If you don't run power to the gate you could run a single 20 amp circuit to the shed.

 

Thanks for the reply! I was thinking on going with the solar powered gate as well, just thought it would be cheaper to run power to it?

 

Another question, in the outside breaker box, it only has 1 neutral bar for ground, is it ok to run the black hot wire to the 20amp breaker, and the white neutral and ground to the same neutral bar? Thank you!!

 

Yes. At the first panel* the ground and neutral are combined. It is under current code** the only place they are combined.

*First panel is defined as the first panel with an OCPD (Over Current Protection Device) breaker are fuse.

**While current code says only the panel with the first OCPD has neutral and ground combined you will see neutral and ground combined at sub panels in older installations. Those are grandfathered.

 

Thank you very much! I appreciate all your help!