I have run wires from my main box to the location where I wish to install my spa. I have 3 10 gauge wires (2 power, 1 common) all underground in conduit. Do I sink a rod in the ground for the ground or do I need to run another wire from the box? What are my options? I have also run wires to my shed, do I do the same here?

A ground rod will not be adequate nor allowed. A green equipment ground wire is needed at both the spa and subpanel.

#10 wire is only good for 30 amp circuit with a 26 amp load. Most spas are larger, are you sure #10 is adequate?

Kevin is right on the money as usual. Most spas with electric heater require at least a 50 amp GFI. He can also give you some info about the required disconnect.

A ground rod will not be adequate nor allowed. A green equipment ground wire is needed at both the spa and subpanel.

#10 wire is only good for 30 amp circuit with a 26 amp load. Most spas are larger, are you sure #10 is adequate?

Thanks for the help. I will run four 10 gauge from the house box to the spa box.