Need to install a sub-panel off a 200amp service main panel that will be situated next to each other via 1" pvc conduit from bottom of each. The sub-panel is being installed to accommodate/supply a new hot tub with the manufacturer's recommended 50amp feed. And yes, there is a shut-off box (w/50amp GFCI breaker) being installed 6 foot away from hot tub and completely in line of sight. And yes, I know not to bond the sub.
A couple of questions: 1) Since main is full, I need to remove 2 (probably) breakers currently in the main panel to be relocated to the sub-panel to allow a 70amp breaker as feed for (and shut-off for) the new sub-panel. Is #6 THHN large enough, or would #4 be preferred, figuring the four wires needed, i.e. red, black, white and green?
2) Also, since the removal of the 2 breakers from the main (allowing space for the "feed" breaker) will reside in the sub-panel, am I allowed (with code and safety in mind), to add more same gauge wire length to the wires via wire nuts to reach the new location in the sub-panel?
3) I'm under the impression that the new sub-panel will not need its own ground rod due to its location to the main. I'm also under the impression that the hot tub shut-off box should probably have a ground rod of its own. This area, up on the side of a mountain is notorious and horrific, at best, for any kind of digging or attempting to drive an 8 foot stick in the very rocky ground. Is there anything else that can be done to duplicate what a ground rod would do that is considered acceptable?
Thanks for any and all responses!