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burgerj · Jul 23, 2008, 08:37 AM

I am running NM-B #6 3 wire w/ground from my panel to a J box that exits the house (all indoors at this point). From that point I have about a 40 ft. run to the spa. I have trenched and laid conduit for the remainder of the run. Can I remove the sleeve on the NM-B Romex and use this wire for the outside run in the conduit plus an insulated ground? My understanding is that the conductors in the NM-B Romex is thhn/thwn rated.

Thanks

KISS · Jul 23, 2008, 08:49 AM

You can run the NM-B with the jacket as long as you meet the conduit fill requirements of 40% left of cross secional area and its wet rated.

I suppose you could remove the sleave since the wires are THWN rated. You can run a bare ground.

tkrussell · Jul 23, 2008, 11:04 AM

NM-B cable contains only THHN insulation, and is not rated for wet location, therefore cannot be installed in a conduit that is outdoors or buried underground.

See attached product cutsheet for actual data froma popular Romex manufacturer.

The Romex will need to stop at a junction box in the home, and then the circuit will need to continue on with conduit and pulled in THHN/THWN wiring.

Washington1 · Jul 23, 2008, 01:44 PM

Originally Posted by KeepItSimpleStupid

You can run the NM-B with the jacket as long as you meet the conduit fill requirements of 40% left of cross secional area and its wet rated.

I suppose you could remove the sleave since the wires are THWN rated. You can run a bare ground.

Keep,

See Chp 9 T.1 note 9.

stanfortyman · Jul 23, 2008, 07:09 PM

Also, burgerj you are correct. The ground MUST be insulated.

Sparky3000 · Jul 23, 2008, 07:54 PM

Also Your grounding conductor can be BARE as long as it is concealed or enclosed within the wiring method recognized in CHAPTER 3 of this Code.( REFERENCE Art 680.42(C) of the NEC2005) You also must install a disconnecting means no closer than 5 ft away from the SPA but still with in sight of it.

tkrussell · Jul 24, 2008, 03:02 AM

Sparky, did you really read my answer? I stated WET location, I did not mention DAMP location. There is a difference between the both.

Did you read the spec sheet I provided? No where does it state WET locations, in fact it does state "Not wet or damp locations" in the first paragraph. Seems to back up my advice and counters your disagreement.

I also direct you to NEC Section 334.12 (B) (4) "Uses Not Permitted" for NM cable, states NM cable is NOT allowed in Damp or Wet locations.

While THHN is allowed in damp locations, as per NEC 310.8 (B), it is not allowed in wet.

Once THHN is part of NM-B cable, now it is not even rated for damp locations, period. Note,the spec sheet for the NM-B cable does not mention or admit the insulation of the internal wires are covered with THHN.

Since I am stating the facts of NM-B cable in wet locations, and all you mention is damp for THHN, you are talking apples to oranges, therefore your disagreement is irrelevant.

stanfortyman · Jul 24, 2008, 03:34 AM

Originally Posted by Sparky3000

Also Your grounding conductor can be BARE as long as it is concealed or enclosed within the wiring method recognized in CHAPTER 3 of this Code.( REFERENCE Art 680.42(C) of the NEC2005) You also must install a disconnecting means no closer than 5 ft away from the SPA but still with in sight of it.

True, while it is IN the structure. We are talking about the outside portion of the wiring here, aren't we?? Read the OP.

Do you need me to quote the code section for this?

stanfortyman · Jul 24, 2008, 03:51 AM

Originally Posted by Sparky3000

NM-B Jacketed wire contains THHN rated conductors which are Dry or damp locations at 90 deg C. Or wet and in oil at 75 deg C.

HOW can you disagree with what TK wrote??

True, the conductors must be rated a certain way, but NM cable is NOT rated for damp or wet locations, regardless of what conductors are inside.

334.10 Uses Permitted
(A) Type NM Type NM cable shall be permitted as follows:
(1) For both exposed and concealed work in normally dry locations except as prohibited in 334.10(3)

An underground conduit IS a wet location!

Washington1 · Jul 24, 2008, 06:32 PM

Did sparky erase a portion of his response, because I don't see where he/ or she said: NM-B Jacketed wire contains THHN rated conductors which are Dry or damp locations at 90 deg C. Or wet and in oil at 75 deg C.

Sparky,

You are off base on this one.

Sparky3000 · Jul 24, 2008, 10:43 PM

Originally Posted by stanfortyman

HOW can you disagree with what TK wrote???

True, the conductors must be rated a certain way, but NM cable is NOT rated for damp or wet locations, regardless of what conductors are inside.

334.10 Uses Permitted
(A) Type NM Type NM cable shall be permitted as follows:
(1) For both exposed and concealed work in normally dry locations except as prohibited in 334.10(3)

An underground conduit IS a wet location!

So what happens if you strip the jacket off the cable and install it in conduit?
I will admit if I am wrong but then I need to tell my inspectors they are too! Because I have done several spas in the last 16 years in fact I just did a spa a couple of months ago and had it pass no questions asked and all I did was strip the jacket off where it exited the house and ran it through a 3/4" romex connector into a 3/4" female adaptor into an LB down to 18" below grade (to top of conduit)for 20 feet then up to a disconnect and then I switched to THHN (The only reason I switched to THHN was It was another 25 feet to the SPA and regular THHN is easier to pull especially though carflex) and I ran carflex where I stubbed up out of the concrete pad under the spa and tied it into the control panel and this passed inspection. (AND YES HE DID LOOK AT THE WHOLE JOB) BTW I am a "HE" and I've been an electrician for 16 years and the last 8 of those as a MASTER ELECTRICIAN. If you like I can give you where and when I passed my test and my Licence number.

tkrussell · Jul 25, 2008, 02:56 AM

The issue is wet location, as an underground or outdoor raceway.

With the previous cut sheet I provided, I noted that Southwire does not even mention THHN on the internal wires, which stand alone would only be allowed in damp or dry locations. Only mentions PVC insulation.

Here are two other manufacturers that mention the same.

http://www.unitedcopper.com/specs/wire/NMB_sheet.pdf

NMB

Stripping Romex and pulling through the conductors through a underground conduit or outdoors is not allowed by NEC or UL.

The wires are not rated for wet locations. These wires are part of the assembly of NM-B cable and are only allowed in dry locations.

While we in the trade all know it is very similar to THHN, the manufacturer has not rated it as such. Try finding any markings on the wires inside a piece of Romex.

Any wire insulation that is allowed in a wet location must have a "W" in the designation, such as THWN, XHHW, TW, THW, and so on.

Perhaps you can convey this onto any inspector that does allow stripped Romex through a wet location. They should thank you for the information.

If I was the inspector for the insurance carrier doing an claims inspection after a fire, I can easily call this a violation, and cause the carrier to deny or reduce any claim.

This is what happens when data sheets are not referred to ,and only assumptions are made.

And Washington is correct, there is that statement missing.

stanfortyman · Jul 25, 2008, 04:16 AM

Originally Posted by Sparky3000

Because I have done several spas in the last 16 years in fact I just did a spa a couple of months ago and had it pass no questions asked and all I did was strip the jacket off where it exited the house and and ran it through a 3/4" romex connector into a 3/4" female adaptor into an LB down to 18" below grade (to top of conduit)for 20 feet then up to a disconnect and then I switched to THHN (The only reason I switched to THHN was It was another 25 feet to the SPA and regular THHN is easier to pull especially though carflex) and I ran carflex where I stubbed up out of the concrete pad under the spa and tied it into the control panel and this passed inspection. (AND YES HE DID LOOK AT THE WHOLE JOB) BTW I am a "HE" and I've been an electrician for 16 years and the last 8 of those as a MASTER ELECTRICIAN. If you like I can give you where and when I passed my test and my Licence number.

All I can say is WOW!
Your inspectors have NO clue.

I don't fault you (much). I have seen many "real" electricians who know very little about pools and spas, yet work on them all the time.

I say I don't fault you "much" because YOU are supposed to know the codes as well as the inspector. The inspector is not supposed to guide you through a job and tell you codes. He is supposed to catch mistakes and forgotten things.

TK gave you all the correct information about NM cable and the conductors inside.
Here are the code sections regarding wiring an outdoor spa.

IV. Spas and Hot Tubs

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 680.42(B), that would otherwise apply to pools installed outdoors.

II. Permanently Installed Pools

680.21 Motors
(A) Wiring Methods
(1) General The branch circuits for pool-associated motors shall be installed in rigid metal conduit, intermediate metal conduit, rigid nonmetallic conduit, or Type MC cable listed for the location. Other wiring methods and materials shall be permitted in specific locations or applications as covered in this section. Any wiring method employed shall contain an insulated copper equipment grounding conductor sized in accordance with 250.122 but not smaller than 12 AWG.

stanfortyman · Jul 25, 2008, 04:17 AM

Originally Posted by Washington1

Did sparky erase a portion of his response, because I don't see where he/ or she said: NM-B Jacketed wire contains THHN rated conductors which are Dry or damp locations at 90 deg C. Or wet and in oil at 75 deg C.

This is in the disagreement comment on post #3.

Sparky3000 · Jul 25, 2008, 05:33 PM

Point duely noted... I will not make that mistake again.

donf · Jul 25, 2008, 06:56 PM

Just a question here, please.

If you strip off the sheath surrounding NM cable, the individual conductors carry no markings as required by code. So how did the unmarked conductors pass inspection?

stanfortyman · Jul 25, 2008, 07:12 PM

Originally Posted by donf

So how did the unmarked conductors pass inspection?

At the same time how did a bare ground pass inspection? Hence my earlier comments.

tkrussell · Jul 25, 2008, 07:18 PM

Inspectors are not required to check every little detail. And no one could be expected to. They are held harmless from any liability.

The complete responsibility falls under the permittee, typically the master electrician, for a code compliant installation. Even if the job was engineered by a PE, EE, or any discipline, the installer takes all responsibility for code compliance.