# Wire in RIgid conduit



## simeon2014 (Nov 17, 2019)

I plan on running off of a bowers box from an existing outlet on the deck to a location further out by her gazebo to provide power for her fan and lighting {in the gazebo}. 

I'm going to run Imc or Rigid {haven't decided yet}.

If the run is only 40 feet, would it be against code to run thhn wires through my run for the outlet?


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## Dennis Alwon (May 9, 2009)

How are you terminating the conduit on both ends? Are you an electrician or just doing electrical work?


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## Speedy Petey (Jan 10, 2007)

simeon2014 said:


> I'm going to run Imc or Rigid {haven't decided yet}.
> 
> If the run is only 40 feet, would it be against code to run thhn wires through my run for the outlet?


I see in another post you say you have been an electrician for six years. Are you seriously asking if you can run THHN in conduit?


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## 99cents (Aug 20, 2012)

We have a chart in our book with conditions of use for wire and cable. I’m sure the NEC does too.


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## CWL (Jul 7, 2020)

99cents said:


> We have a chart in our book with conditions of use for wire and cable. I’m sure the NEC does too.


Is there an Ugly's book Canada edition?


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## 99cents (Aug 20, 2012)

CWL said:


> Is there an Ugly's book Canada edition?


Don’t think so but, if we did, it would be called Pretty’s.


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## CWL (Jul 7, 2020)

99cents said:


> Don’t think so but, if we did, it would be called Pretty’s.


And a version in French would mandated.:biggrin:


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## HertzHound (Jan 22, 2019)

Somewhere on the insulation, it has to have a “W” on it.


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## Bird dog (Oct 27, 2015)

99cents said:


> We have a chart in our book with conditions of use for wire and cable. I’m sure the NEC does too.


 It does but it also says it's not a design manual (specification) for untrained persons NEC 90.1(A).
Does the OP have a card or finish an apprenticeship?


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## macmikeman (Jan 23, 2007)

The Canadian Ugly's would also say something about using rigid when pvc is a better option


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## simeon2014 (Nov 17, 2019)

Dennis Alwon said:


> How are you terminating the conduit on both ends? Are you an electrician or just doing electrical work?



There's a recessed outlet outside on the deck. I'm going to use a bowers extension ring from that point, and piple under the dirt to her gazebo in the backyard....

I'm going to set up an outlet point there to provide power.

The basics of the question is....

Can i get away with using thhn...or do I have to use thwn.
I'm asking on the particular wire I have to use being that it's outdoors.


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## 99cents (Aug 20, 2012)

macmikeman said:


> The Canadian Ugly's would also say something about using rigid when Teck is a better option


Fify


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## Speedy Petey (Jan 10, 2007)

simeon2014 said:


> Can i get away with using thhn...or do I have to use thwn.
> I'm asking on the particular wire I have to use being that it's outdoors.


It would need to be THWN. 

Thing is, can you even get wire that is not dual rated THHN/THWN? All the stuff I can get is both.


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## MotoGP1199 (Aug 11, 2014)

HertzHound said:


> Somewhere on the insulation, it has to have a “W” on it.


Found it

"South*W*ire, THHN, 12 A*W*G", actually found two.


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## Weasel (Jul 14, 2019)

THHN is legal and is approved for wet locations even if it’s in conduit and use IMC conduit because it’s cheaper. THHN is the same as THWN


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## Coppersmith (Aug 11, 2017)

Weasel said:


> THHN is legal and is approved for wet locations even if it’s in conduit and use IMC conduit because it’s cheaper. THHN is the same as THWN


THHN is not legal for wet locations. THWN can be used in wet locations. THHN and THWN are not the same thing. All the THHN I have even seen is dual rated as THWN, however if you find some that is not dual rated, you can't use it for wet areas.


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## paulengr (Oct 8, 2017)

Coppersmith said:


> THHN is not legal for wet locations. THWN can be used in wet locations. THHN and THWN are not the same thing. All the THHN I have even seen is dual rated as THWN, however if you find some that is not dual rated, you can't use it for wet areas.



If you look closely it’s probably THHN-2 and THWN-2. The limitation with THWN is the lower temperature rating and THWN-2 fixes that. Similarly THHN-2 fixes the wet location issue so the result is a dual rated universal cable since performance wise there’s not much difference.


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## simeon2014 (Nov 17, 2019)

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Coppersmith said:


> THHN is not legal for wet locations. THWN can be used in wet locations. THHN and THWN are not the same thing. All the THHN I have even seen is dual rated as THWN, however if you find some that is not dual rated, you can't use it for wet areas.


Thanx man - 

To my knowledge, Rigid metal conduit has to be buried at least 6" underground, correct?

What are the issues with corrosion with this?

I'm going to go from a bowers box attached to an outlet recessed with the house, all the way out to her gazebo on a concrete pad in her back yard . . . 

This is to mount a standing receptacle for her gazebo lights and fan . . . 

Is running 40' of rigid under 6" of dirt against code? Do I have to do pvc . . . which requires 24"....


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## macmikeman (Jan 23, 2007)

pvc and 120 volt circuits protected by gfi at source only need 12" burial depth in the USA. Best to use schedule 80 though if coming out of the ground unprotected


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## simeon2014 (Nov 17, 2019)

macmikeman said:


> pvc and 120 volt circuits protected by gfi at source only need 12" burial depth in the USA. Best to use schedule 80 though if coming out of the ground unprotected



Well Im only looking into Rigid first because I don't have to dig as far.
Is Rigid a bad idea due to corrossion potential? Sorry for the questions . . . I just want to make sure it's up to code and works out for the lady . . . Want to get my pricing right from the materials needed.


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## Coppersmith (Aug 11, 2017)

simeon2014 said:


> What are the issues with corrosion with this?


AFAIK there are no corrosion issues. Rigid is zinc coated and designed to be direct buried. I'm sure it will corrode eventually, but it will take many years.



simeon2014 said:


> Bowers box from house


I was unfamiliar with the term bowers box so I looked it up. Bowers make a bunch of different boxes, but I didn't see any weatherproof ones. Make sure you use a weatherproof box from Bell or wherever. 




simeon2014 said:


> Is running 40' of rigid under 6" of dirt against code?


You can run rigid under 6" of dirt for 4000 feet if you want to. It's allowed in the code. (Just account for voltage drop.)


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## MotoGP1199 (Aug 11, 2014)

Also 6" is from the top of the conduit. Not the depth of the trench.

Sent from my SM-G973U using Tapatalk


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## simeon2014 (Nov 17, 2019)

Coppersmith said:


> AFAIK there are no corrosion issues. Rigid is zinc coated and designed to be direct buried. I'm sure it will corrode eventually, but it will take many years.
> 
> 
> I was unfamiliar with the term bowers box so I looked it up. Bowers make a bunch of different boxes, but I didn't see any weatherproof ones. Make sure you use a weatherproof box from Bell or wherever.
> ...


Thank you so much dude. Trying to price for a decent sized job . . . young sparky here is a little nervous.


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## macmikeman (Jan 23, 2007)

simeon2014 said:


> Well Im only looking into Rigid first because I don't have to dig as far.
> Is Rigid a bad idea due to corrossion potential? Sorry for the questions . . . I just want to make sure it's up to code and works out for the lady . . . Want to get my pricing right from the materials needed.


MY guess depends on conditions of soil and the trench. If straight then: Rigid new is fairly easy to screw together and if you run it all up out of the trench and push it in the trench in one piece it's pretty quick to run a few hundred feet disregarding the time it took to do the trench. Put some bends in the trench and the time taken to install goes up 30%. Put some custom cuts and threading into the trench for multiple direction changes and less than factory 90 deg bends the time goes up 70%. 

TRENCHING 6" VS 12" FOR A GFI PROTECTED PVC RUN- ALL SOIL DEPENDENT. 

If it's rocky, hard clay, both trenches are going to take lots of time. In sand you wouln't hardly notice much of a difference for a say 30' trench. At 100 ft it will be quite a bit of time saved with a 6" trench over a 12" trench. (actually usually would be 8" deep and 14" deep due to measurement of depth starts at top of pipe. 

I'd rent a ditch witch for anything over 15 feet anyway. We did a 200 foot long trench in clay/ topsoil conditions a handful of years ago with a ditch witch and it took about 3 or 4 hours for the 19" deep trench thru that, and another couple of hours to get all the plastic conduit into it. Refill takes the most time when a witch was used. That part was done by another company.


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## Yankee77 (Oct 5, 2020)

simeon2014 said:


> There's a recessed outlet outside on the deck. I'm going to use a bowers extension ring from that point, and piple under the dirt to her gazebo in the backyard....
> 
> I'm going to set up an outlet point there to provide power.
> 
> ...


See article NEC 310.10(C)


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