when we did ours, we got a material list from the electrician and bought our own, that saved us some money on the electrical side of the installation, as most electricians upcharge materials.
also, on the code side--here, it states the shut off box has to be within view of the hot tub too.
Good deal that he let you do that. The disconnect must be within line of sight of the spa, no closer than 5' or farther away than 50' from the water, or that's how it was when I did mine. Inside a building doesn't count (unless you're inside too), around corners don't count either.