What guage wire to use

[jimmyj]

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]

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]

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]

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

 

[Heywood Jannockitov]

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]

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]

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

,,,NO.

 

[jimmyj]

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

 

[gary49]

#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]

#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.

 

[jimmyj]

Yes, there are 4 wires in total, red black white and ground. I'd rather be a bit over than a bit under too.

 

[LD1]

8-3 UF wire si good for 40A.

Wondering why your electrician is suggesting 6-3? (which is good for 55A). Maybe because he already has some on had?

Also, not sure what type of breakers you have, but it may be a bit difficult putting 6ga on a 40A breaker.

As far as length, you can go to 125' pulling 40A on 8ga before you exceed 3% voltage drop. So I dont see that being a reason to upsize wire either.

Now you may want to see if there is anything you can do to get the circuit length to 50'. Wire comes standard in 25', 50', 125', 250, etc rolls. See if you can make 50' work and not have to buy 125' of wire, and not use 70' of it.

BTW, 50' 8-3UF is ~$90
.......125' 8-3UF is ~$190

 

[jimmyj]

I bought the 6 3 yesterday. Actually needed 18 meters and it cost 244.00. Everyone I talk to says use #6, I assume it's a local standard.

 

[LD1]

Wow, thats pricey. Can get 50' here for ~$110 and 125' for about $300

 

[buickanddeere]

Usually a good idea to run a 12/3 out there at the same time to power a pair of 20amp T-slot GFI plugs in the yard.
Either net for wifi too.

 

[jimmyj]

Wow, thats pricey. Can get 50' here for ~$110 and 125' for about $300

Welcome to Canada, the land of the overcharged.