On Thu, 21 Jul 2016 05:22:31 -0700 (PDT), TimR
wrote:

I would forget about a breaker box. The wire is probably 10 gauge
to alleviate voltage drop. Just install a junction box and wire your
outlets and lights from that. Black is hot, white is neutral, green is ground.

John Grabowski
http://www.MrElectrician.TV

And, properly label the breaker back in the house. It says pond now (ho
pefully) and it needs to say shed. What size is that breaker?

That house breaker is likely a 30A. Way too large for any outlets or
lights. It needs to be changed to a 15A or 20A. (20A will require 12
gauge wire to all devices, but the existing 10 gauge is fine).

However, we are not sure if this is 120V or 240V.

I also recommend getting an electrician, or at least finding a friend or
neighbor who knows what they are doing.