Using 6-2 NM outside question?

[Jac-470]

I'm trying to understand this code.

Also the use on NM cable for this installation can be used for this part of the installation
 (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.
 
I ran 6-2 NM from my sub panel inside to my disconnect just outside in liquid tight conduit. Then I ran # 6 THNN from disconnect to spa. From reading this code, this is allright??

[ssilver853]

Most tubs require 6/3 to your shut off / GFCI... And then you can your two hots and an insulated ground to the tub... Any wire in conduit should be THHN.

Hope that helps!

[Jac-470]

I had to install a sub panel as the main was full. So I put the 60amp GFCI in the sub. I then ran 6-2 to the disconnect switch which is 5' from the hot tub.

[TdiDave]

Few things that may be a issue:
6-2 NM cable is not rated for 60amp.
NM cable does not have a insulated ground.
NM cable is not allowed in conduit.

[Jac-470]

From what I have read, THNN is stranded and individual so it's  more flexable and easier to pull through conduit, while NM has the jacket so harder to pull. Yet side by side they both are identicle as far as the insulation goes as I have both. So both are rated from what I read at 55amps. The only difference is the grounds as one is insulated and the other is not. Yet I can use the Romex inside, so what does the insulated ground do outside that it doesn't need inside? Plus it would seem better to have no splice between GFCI and disconnect. The liquid tight is not buried and is only exposed about 5-6' on the side of the house.

[TdiDave]

#6 THHN is 75amp at 90c
#6 NM is 55amp at 60c

Not to disagree with some of your logic as I had this discussion with the electrician and code inspector. 

To meet (or exceed) code mine was ran with 6-3 MC cable (has a insulated ground) from my breaker box in the basement into the GFCI disconnect mounted >5 feet from tub within line of sight. Then single #6THHN red,black and green in ridged PVC conduit into the tub.

[Jac-470]

So it sounds like I could strip the jacket off the NM as it has THHN in it and then run a insulated ground instead of the bare ground?

[TdiDave]

Maybe this can help ?

[Jac-470]

From the disconnect to the tub I have all 3 THHN in liquid tight. It's from the panel to the disconnect is where the NM wire is. 42' is in the basement, then a 1" transition outside to 1" liquid tight along side the house about 5-6', then under my enclosed deck 12' to my disconnect. So it's one 60' pull of 6-2NM from panel to disconnect.

[HuMan321]

Not an expert on spa codes, but I believe liquid tight (are you using non metallic?) Needs to be limited to 6 feet or less in length which is why you typically see PVC for most of branch run and then short flexible connection

[Jac-470]

Not an expert on spa codes, but I believe liquid tight (are you using non metallic?) Needs to be limited to 6 feet or less in length which is why you typically see PVC for most of branch run and then short flexible connection

The liquid tight will be about 6' from the disconnect to the tub. But from the transition to the disconnect there is no limit as it's a non-matallic conduit as it's grounded inside.

[Hollywood]

Most tubs require 6/3 to your shut off / GFCI... And then you can your two hots and an insulated ground to the tub... Any wire in conduit should be THHN.

Hope that helps!

For a 60 amp spa you need a minimum 4/2 NM cable or #6 thhn ran in a conduit.  Those are under the best of conditions.  If you live, like I do, in the middle of the desert (Arizona) there are deratings that have to be done because of the heat.  Everything else you did is fine.  I don't really like to use PVC above ground but that is a personal choice because I live in Arizona the sun bakes it pretty bad.

Oh, I have been an electrician for over a decade.

[Jac-470]

I live in NH, so heat isn't really a issue. We may get a few 90 degree temps in July and Aug., but it doesn't last long. I plan on pulling the 6/2 out of the conduit and taking the jacket off as the lines inside are THHN. Then adding a insulated ground. Tubs running great now in the cold, so I will wait untill it warms up a bit. Thanks for the info.