From memory you said your LOCAL CODE requires a #6, if you ever plan to sell the place OR if something happens at the SPA and you did NOT wire it to LOCAL (and Fed Codes) then your insurance or sales may not pass/go thru...
That said the wire in the wall is NORMAL & could be used under normal conditions.
Bonding and Grounding are two different subjects, Bonding refers to tying the Neutral to the Ground or bonding the frames of equipment to the ground system/systems. Also note that if you are running a separate Sub Panel then that panel's Neutral must not be Bonded to the Ground Bus in that panel (from last ver of NEC not sure if that remained or not as I have not updated my NEC books as I'm out of the buis.)
Mark
Hey Mark! I don't recall mentioning my local code. If I did, I sure didn't mean to. Where I'm at, whether right or wrong, there is no code, no inspectors, no permits to pull, nothing. I just want to do the right and safe thing and don't understand the basis for the #6 wire requirement. I really and truly don't want to have to open my wall (and attempt to match the texture again!) if there isn't benefit, but want to be safe as well. We all know that safety and 'code' don't necessarily go hand in hand (in other words, you can be perfectly safe and not 'to code', but I am also mindful of the fact that the code is there for a reason that extends far beyond bureaucracy - it's *primarily* (or at least mostly) to keep the current people safe from themselves and future people safe from the poor implementations of earlier folk. I completely respect that.
My house is built well beyond 'code' in so many respects, but I hate going back and re-doing stuff at the same time, especially if it doesn't need to be.
In this application, the 70 amp spa panel is fed from a 200 amp main panel that is in turn fed by a meter panel with a 200 amp breaker. A grounding rod is connected to the main panel, but I don't recall the wire size connected to it - it's something like a multi-strand cable with maybe 5-7 #10 wires IIRC.
Regardless, what a great discussion! I haven't been able to be on this board near as much I used to be, but know that I can always count on TBN when I need it. What an amazing set of people on here! Thank you!
Inspector507 - do I remember that you are in electrical inspector by trade?
s219 - You said that wire length has nothing to do with 'allowable' ampacity. Do I correctly understand that then that a #14 wire, for example, that is rated for 15 amps of current, but happens to be at, say, 20' in length, simply cannot handle a, say, 30 amp draw - that it'll turn into a fuse, or minimally run hot and be a fire hazard?
CobyRupert - You say that #10 is good for up to a 60 amp circuit. In this case, a singular ground wire is handling a 70 amp PANEL, but one with a 30 amp GFCI, a 20 amp GFCI, and a second 20 amp GFCI breaker. It would seem logical, that any fault would impact only one of these breakers at a time, meaning that the #10 is actually MORE THAN plenty - for the same reason that the #4 wire evidently commonly used as ground in a 200 amp panel,is sufficient (surmising that this basis has to do with the max supported breaker size of 100 amps in that panel).
CobyRupert#2 - Thanks a ton for the grounding explanation. You said that 'low resistance allows (Ohm's Law) a large enough short circuit to flow so that the circuit breaker trips'. Doesn't resistance also increase with wire length? IOW, if the instruction manual calls out #6 wire for a run up to 100' and my run is only about 34', wouldn't the resistance on that length be less - as indicated actually by the voltage drop calculation?
PMteejk - Re: a sparkie being pretty good at fishing wire. The reason why the sheetrock would have to come down is that the exterior wall with the subpanel is an Insulated Concrete Form wall - no voids to fish in like with 2x construction. The seemingly huge mistake was not putting this wire in conduit - a mistake I won't make again if the wall is coming open, for sure.
I'm totally not trying to be 'textbook' or 'professor-like' on this - I just want to be safe and recognize that the sheetrock work etc will pale in comparison to someone getting shocked (killed) by an improper install.
Everyone's input is HUGELY appreciated. It is clear that you guys know more about this than I do. THANK YOU!