I want to to run power to my trap shed. Right now the shed is wired and powered by a 30amp generator outlet with 10g wire feeding the breaker box. I need to run about 130ft of wire to an outside junction box. Is 10g AWG wire appropriate and do I just splice into the wires in the junction box ?

BTW pics are turned 1/4 turn to the left.

If I remember correctly.....any run over 100 feet requires the next larger awg

How much power are you drawing to power what? It looks like you have room to add more breakers unless your running freezers, A/C or other big draw appliances 10 ga might be unnecessary.

I just hand trenched a 12 ga underground wire to my storage container for about 40 feet of distance to power lights and a few sockets I just ran it off of my fur shed box on a new breaker I added.

Overhead lights and wall outlets. That's it. I do have my skinning winch plugged in but otherwise I run a radio and maybe battery charger for Dewalt 20v tools. I may want to run a freezer in the future.

In order to have a light switch and dealing with the issues of wiring a metal box I used a plug switch combo, the lower switch/plug in allows me to have power to a socket at all times and the switch controls the lights power and gives me a second socket if needed. Nothing fancy but it fits the need the easiest way I could do it.

Figure what you have to work with first some of that box wiring looks a little light to me scary light but I’m no electrician.

Power full time to bottom plug from fur shed breaker box, top switch power on/off to lights. Lights will plug into the double socket above leaving another plug in socket if needed. This allows for simple light replacement just unplug any bad light and replace it with a new light just snap out snap in the replacement. Any light in the line can quickly be changed out in minutes no more wiring needed.

I ran 15 and 20 amp sockets along my fur shed wall then put white covers on the 15 amp plugs and gray covers on the 20 amp plugs. Unless you’re running over a 18,000 BTU A/C unit you should be fine. 10 Ga to 12 ga is plenty then run a small 2 breaker breaker box if you want to break up the draw or go more poles if you want to add other draws later then you can pick what amp wire you want to run most lights use 15amp breakers depending on how many and what type lights are drawing the juice. The LED lights I have says you can run 5 lights off of a 15 amp plug.

YouTube has a ton of electrical info on it just search what you’re looking for I found it very helpful.

6 pole breaker box $26 at Menards and breakers $15-$20 depending in amp size would give you a lot of possibilities for future add on needs.

Hummmm. Looks like your bond screw is removed? What's the wires taped red green & white? Feeding from a house, you'll need a bonding conductor besides your neutral, unless you put a ground at the shed panel....but the panel you got isn't service entrance rated. The bonds you got terminated in the buss are kinda just floating there if the bond strap/screw is removed. In the event of a high resistance fault, she'll just keep cooking. I would just jerry rig it if nobody's gonna live in there and no inspector's coming around, but you're probably going to want your breakers to operate if something goes awry. Don't keep anything you can't replace in there in case it burns down....lol.

That long of a run will require a larger ga wire to handle the current.

Red and green wires? Where’s the 10 ga wires? Is that generator wiring?

Sometimes ya just better off calling a professional

the voltage drop.

Pic #2: red, green,black, white, orange - is the feed from the house. It's on its own breaker. The orange wire is not connected to anything.

The black wires with red and white tape on them is coming from a old detached garage. They lead to a breaker box with two 15 amp breakers.

The 10g wire is connected to the generator outlet and feeds the box in pic #1.

Instead of going to 8/2 with ground to handle the voltage drop for 30 amps, I think I'd buy 10/3 with ground and two 20 amp legs.

Not good to run 10/3 - that would be sharing the neutral. Above all that outside shed should be GFCI protected. Not only to save your life but someone else too.

It would be horrible if the two hots are on the same phase. But if they're on separate phases the nuetral only carries the imbalance.

Neutral is to 'float' (grounds and grounded conductors are to remain separate) after 1st point of disconnect per NEC. 1st point of disconnect in this example would be the service/meter back in the house where this power originated.
Anything 18" ancillary of the 1st point of disconnect constitutes an extended service and the neutral and ground must remain separate.
To do otherwise would be to parallel your ground and neutral. Not good.

That is my understanding as well. Any sub-panels downstream from the main panel/service disconnect should not have shared neutrals and grounds. Throw that panel bonding screw away.

All sub-panels should also have their own ground rods.

Correct. The submersible pump wires the feed and the bonds are all in the same buss, green screw removed. Someone must’ve known a little bit when they fooled around in there…..lol
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So the 3 conductors come from an old garage, or feed an old garage? Without seeing the big picture, it’s tough.