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Discussion Starter #1 (Edited)
I have looked through these forums and the internet and found hundreds of close answers, but no definitive answer. With that....

I am installing an outdoor hot tub (obviously). It will be on a concrete pad with 5 feet of 1-1/2 conduit underground, entering the house above ground level. The main breaker panel is 15 feet away inside. On the wall out side i have put a C/H 50Amp Spa panel (with GFCI/disconnect). I have 1-1/2" conduit running up to the disconnect. All standard, but here is the question I can't get a straight answer to:

I need to use 6 gauge wire - however, I understand I can not use 6/3 NM-B or UF-B in the conduit. I understand that I need to use individual 6 gauge THWN wire in the conduit. Am I right to understand that I can not run the individual wires along the joists in the basement outside of conduit? If that is so, then it would mean I need to either run conduit from my main panel to the disconnect and then from there to the spa, or I need to run NM-B to a junction box, connect it to THWN and then out through the conduit to the hot tub. Is that correct?

Since it sounds like no matter what I'll have to use the individual THWN wire, does it HAVE to be indiviual colors, or could I get a bulk spool and identify each of them separately?

edit>> I just found this:
Color Code
In addition to the identifying markings described above, NEC also requires that the insulation on individual conductors be color coded in order that conductors being used for certain specific purposes may be identified.

NEC 250.119 states that the grouding conductor may be bare, covered, or insulated. When covered or insulated, it shall be colored green or green with one or more yellow stripes.

Article 200.6(A) states for sizes AWG 6 or smaller an insulated grounded conductor shall be identified by continuous white or gray outer finish or by three continuous white stripes on other THAN green insulation along its entire length. Wires finished white or gray but with colored threads showing are permitted. With mineral insulated metal-sheathed cable mark the ends at the time of installation.

NEC 200.6(B) states that for sizes Larger than 6 AWG if the insulation is not colored along its entire length per (A) above then it must be marked at its ends per Fig. 4-5.

end edit

I have a good working knowledge of these things however I want to make sure that things are correct. I not aware that UF-B could not run through short conduit outside since it does not have an insulated ground, even though the outerjacket is probably even better protection.

Thank you in advance.
 

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I need to use 6 gauge wire - however, I understand I can not use 6/3 NM-B or UF-B in the conduit.
NM-B, no. But I recall a previous discussion where it came up that UF-B was allowed.. Can someone please confirm (or not)? EDIT: Whoops, missed the point.. not applicable here anyway because UF-B can't be used for a pool/spa, per Speedy's post below.

I understand that I need to use individual 6 gauge THWN wire in the conduit. Am I right to understand that I can not run the individual wires along the joists in the basement outside of conduit? If that is so, then it would mean I need to either run conduit from my main panel to the disconnect and then from there to the spa, or I need to run NM-B to a junction box, connect it to THWN and then out through the conduit to the hot tub. Is that correct?
Yes, the THWN needs to be in conduit the entire way, even in the basement. You can either run conduit/THWN in your basement, or NM-B from a jbox. Of course if you'd have to run the NM-B where it would be subject to damage, then go with conduit. (UF-B can be installed like NM-B in the basement).

Since it sounds like no matter what I'll have to use the individual THWN wire, does it HAVE to be indiviual colors, or could I get a bulk spool and identify each of them separately?
edit>> I just found that: NEC 200.6(B) states that for sizes Larger than 6 AWG if the insulation is not colored along its entire length per (A) above then it must be marked at its ends per Fig. 4-5.
Yes, as you can infer from the above, you cannot re-label (for example) black #6 as white. Though from what I've heard some inspectors would pass you even if you did, some will not. Pretty sure you only need white and black; you can use tape to mark one of the two black wires red.
 

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(You edited while I was typing, so I didn't see part of your post..) It sounds like you do have a good understanding of what's going on, but I just wanted to clarify here:

Article 200.6(A) states for sizes AWG 6 or smaller an insulated grounded conductor shall be identified by continuous white or gray outer finish or by three continuous white stripes on other than [<-- key word missing from your transcription] green insulation along its entire length. Wires finished white or gray but with colored threads showing are permitted. With mineral insulated metal-sheathed cable mark the ends at the time of installation.

That refers to the neutral, not the ground. (Grounded = neut., grounding = "ground"). Just want to avoid confusion.. if not for you, then for the next guy to google this subject.
 

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UF or NM is definitely not allowed outside the structure for a spa or pool wiring. You must use insulated conductors in conduit.

In a one-family swelling you can however use NM cable inside the dwelling and change over the conduit going outside.
 

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Discussion Starter #5
Per the article below, WOULD it be possible to use 6/3 w/ground UF from the panel to the disconnect, then back inside and across, back outside through the conduit and into the ground, across and then up through the pad through a piece of conduit - using conduit only for physical protection of the wire where not buried. I've also gleaned from other reading that UF would be permissible in short spans of conduit being used to protect the wire. Or am I way off base thinking this way?


From Electrical Raceways & Other Wiring Methods based on the 2005 NEC By Richard E. Loyd

When necessary to prevent physical damage to a raceway or cable, select material (such as sand), suitable running boards, sleeves, or other approved means shall be used. Raceways through which moisture may contact energized live parts, such as conductors entering the building from outside into panelboards or switchboards that may contact live parts, shall be sealed or plugged at either or both ends. If hazardous gases or vapors are present, this condition may also require the sealing of underground raceways where they enter the building. A bushing or terminal fitting shall be placed on the end of a conduit or raceway that terminates underground where cables of a type approved for direct burial, such as Type UF, emerge as a direct-burial method. A seal incorporating the physical protection characteristics of a bushing is permitted in lieu of the bushing.
 

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No. Like petey said.
You can use nm-b to power the spa panel inside, but you need thwn to go outside to the spa.
 

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Discussion Starter #7
I guess I've read and heard the same thing over enough times to accept and believe that UF is not acceptable for pools or spas due to the non-insulated ground wire. Which begs the question why they do not make a UF wire WITH an insulated ground, specifically for these instances. Just makes little sense why you can run UF through a yard with a high water table to an outside fixture (not a pool or spa) but not 4 feet to a spa where in all actuality, very little water would be in contact with the ground.
 

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Supply & demand
Most people run conduit & individual wires to a hot tub
With 240v & a Spa I prefer that extra protection of conduit
 

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Discussion Starter #9
WTH... I just called one of the larger contractor supply houses in our area and they don't carry THWN wire. They said that most people just use UF. Could it be as I've read that the NEC is recommendations - not law - and that locally UF is considered acceptable? I'll know for sure when the inspector calls me back tomorrow. Just wondering...
 

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Run uf and sleave with pvc outside the house. Only reason nm-b can't be used is because inside the conduit is a wet location.
 

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Not on a hot tub
Always an insulated ground
I can't believe a supply house doesn't have THWN
Is it an electrical supply place?
Contractor supply - you would think they have it
Not a new employee was it :laughing:
 

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Not on a hot tub
Always an insulated ground
I can't believe a supply house doesn't have THWN
Is it an electrical supply place?
Contractor supply - you would think they have it
Not a new employee was it :laughing:
I bet they have "THHN" if you ask the same guy...
 

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Run uf and sleave with pvc outside the house. Only reason nm-b can't be used is because inside the conduit is a wet location.
This is for a hot tub as has been stated many times in this (and other) threads. UF is NOT allowed for the outside portion of wiring to a spa, hot tub or pool.
 

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Discussion Starter #16
Not on a hot tub
Always an insulated ground
I can't believe a supply house doesn't have THWN
Is it an electrical supply place?
Contractor supply - you would think they have it
Not a new employee was it :laughing:
I had to run to the Homey Depot to pick a few things up and I wandered over to their wire rack and found that they have 6ga stranded THHN/THWN-2. I presume the guy I talked to a the supply house (yes, it was an electrical supply house) must have been new, or nobody ever asked for it as THWN. By far the simplest, cheapest, fastest, and safest way will be to get the individuals and conduit them. Unless the inspector has something different to say tomorrow, I'll plan on that.

Appreciate all the input folks.
 

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I had to run to the Homey Depot to pick a few things up and I wandered over to their wire rack and found that they have 6ga stranded THHN/THWN-2. I presume the guy I talked to a the supply house (yes, it was an electrical supply house) must have been new, or nobody ever asked for it as THWN. By far the simplest, cheapest, fastest, and safest way will be to get the individuals and conduit them. Unless the inspector has something different to say tomorrow, I'll plan on that.

Appreciate all the input folks.
He shouldn't have anything different to say. Stranded in conduit is code. Does your tub require 240V or 120/240V?
 

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Discussion Starter #18
Electrical requirements are 240V 50Amp GFCI with 6 AWG. I'll call (probably another) supply house tomorrow and look for the right wires.
 

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Discussion Starter #20
I just spoke with the local inspector and he has no problem with using UF w/Ground for the entire project. He said as long as the box is properly grounded, that is more than adequate. As long as he'll accept it, I'll probably go that route for the time being as I've got easy access to affordable 6/3 UF. Everything is accessible though so that in the future I may replace the wire in the short span (5ft) of conduit going from the house to the spa.

When it comes down to it, the inspector needs to be the one satisfied I guess.
 
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