What guage wire to use

jimmyj · Jul 10, 2015

Hi all. I have to power a new hot tub. The tub comes with a 40 amp GFCI and the wire run will be 55 feet. What do you guys think for the correct guage? Should I go #8? The wire has to come through the wall of the house from the panel, and will run in a zig zag route around the landscaping underground to the tub so I figure I will get direct burial rated wire and also put it into conduit.

(My neighbour is an electricial so I will be getting a professional opinion but always find TBN'ers to have good ideas too.

RalphVa · Jul 10, 2015

I'd use multi strand wire, whatever size you get. It's a lot easier to deal with than single strand. May not be able to get single strand for that amperage anyway.

Ralph

SPYDERLK · Jul 10, 2015

Yes. 8 gauge is good for that moderate distance. Note that conduit does protect somewhat, but due to insulating the wire from earth cooling effects, will derate the cable slightly. If youre using direct burial cable you might as well take advantage of direct burial.

Egon · Jul 10, 2015

What I think is irrelevant! It's your area electrical code that counts.

Heywood Jannockitov · Jul 10, 2015

What Egon said. Anyway, wouldn't 40 amp require #6? My 40 amp spa GFCI has #6 going to it. 2 hp, 2 spd pump, 4KW heater

jimmyj · Jul 10, 2015

Good comments. I think it is #6 by memory actually now that you say it. Nobody seems to be able to tell me what the code is at the hot tub place or local hardware. My electrician pal will be back in a few days so I better check.

SPYDERLK · Jul 10, 2015

Heywood Jannockitov said:
What Egon said. Anyway, wouldn't 40 amp require #6?

,,,NO.

jimmyj · Jul 17, 2015

So the electrician advises #6 - 3 wire. Expensive stuff!

gary49 · Jul 18, 2015

#8 copper is rated for 50 amps or more, depending on the type of insulation. Doesn't that hot tub require 4 wires? That would be two hots, a neutral and a ground.

SPYDERLK · Jul 18, 2015

gary49 said:
#8 copper is rated for 50 amps or more, depending on the type of insulation. Doesn't that hot tub require 4 wires? That would be two hots, a neutral and a ground.

Itll carry it for sure, but for 3 wire its rated for 40 by NEC. You dont count ground.