On Sunday, May 14, 2017 at 6:49:43 PM UTC-4, Kate wrote:
Excellent point. But, if I decided not to do that, can I just build over the conduit and have it be safe, even if the wires may be connected to the breaker box? The fact that the electrician told me to keep the disconnect key in case I decided to put another hot tub there indicates, to me anyway, that the wires are still connected to the breaker box. He is the one who switched the fuse box switches to "Off".

Is it dangerous to just build over the conduit if I cannot find it?

Maybe I need to hire an electrician as I do want this to be done right.

Happy to see that this great informative group is still here. I have not posted in a long time.

Thanks!

If you're going to build a shed over it and completely abandon it,
then it should be permanently disconnected at the house side, at
the panel, or at least at the disconnect box, which it sounds like
you have. Can a handyman do it? Depends on the handyman. It's
a very simple job for anyone knowledgeable about working on panels
and electric circuits. Is it legal for a handyman to do it? Depends
on the state laws.

If I were the first electrician, I would have either done that or
left the far end above ground, suitably terminated in a simple box.
Which is still an option, if you want the possibility of having another
spa there at some point in the future. Find the cable, bring it above
ground at a suitable spot.