I'm doing some advance work to understand the costs. I was at Lowes looking at wire. They had no 6/3 wire with ground rated at 60 amps. They both were rated at 55 amps. The "multi purpose" was $1.40/ft and the "flat" wire for burying underground (which we don't have to do) was $2.30/ft.
If using the plastic conduit, are you better off going with the conduit with the metal interior for performance or is that hype also? Total ft of wire will be close to 100ft.
No aluminum to the spa, correct? Just copper?
I went with 3/4" nonmetallic conduit w/6gauge THHN pulled through it. "Liquid tight" (flex conduit) connects to the tub and panel. The flex conduit is available in metal core and all plastic, either should be fine.
The "multipurpose" wire sounds like NM cable (aka: Romex), the stuff to be burried underground is UF (underground feeder - not needed above ground).
I don't think anyone uses alum any more (unless for very specilized installs).
Check this out:
IV. Spas and Hot Tubs
680.40 General. Electrical installations at spas and hot
tubs shall comply with the provisions of Part I and Part IV
of this article.
680.41 Emergency Switch for Spas and Hot Tubs. A
clearly labeled emergency shutoff or control switch for the
purpose of stopping the motor(s) that provide power to the
recirculation system and jet system shall be installed at a
point readily accessible to the users and not less than 1.5 m
(5 ft) away, adjacent to, and within sight of the spa or hot
tub. This requirement shall not apply to single-family
dwellings.
680.42 Outdoor Installations. A spa or hot tub installed
outdoors shall comply with the provisions of Parts I and II
of this article, except as permitted in 680.42(A) and (B),
that would otherwise apply to pools installed outdoors.
(A) Flexible Connections. Listed packaged spa or hot tub
equipment assemblies or self-contained spas or hot tubs
utilizing a factory-installed or assembled control panel or
panelboard shall be permitted to use flexible connections as
covered in 680.42(A)(1) and (A)(2).
(1) Flexible Conduit. Liquidtight flexible metal conduit or
liquidtight flexible nonmetallic conduit shall be permitted
in lengths of not more than 1.8 m (6 ft).
(2) Cord-and-Plug Connections. Cord-and-plug connections
with a cord not longer than 4.6 m (15 ft) shall be
permitted where protected by a ground-fault circuit interrupter.
(B) Bonding. Bonding by metal-to-metal mounting on a
common frame or base shall be permitted. The metal bands
or hoops used to secure wooden staves shall not be required
to be bonded as required in 680.26.
(C) Interior Wiring to Outdoor Installations. In the interior
of a one-family dwelling or in the interior of another
building or structure associated with a one-family dwelling,
any of the wiring methods recognized in Chapter 3 of this
Code that contain a copper equipment grounding conductor
that is insulated or enclosed within the outer sheath of the
wiring method and not smaller than 12 AWG shall be permitted
to be used for the connection to motor, heating, and
control loads that are part of a self-contained spa or hot tub,
or a packaged spa or hot tub equipment assembly. Wiring to
an underwater light shall comply with 680.23 or 680.33.