Power to my shed

Reply

  #1  
Old 06-11-12, 02:20 PM
Member
Thread Starter
Join Date: Jun 2012
Posts: 10
Power to my shed

Hello all! New to the forum and I had a quick question. I ran 2 inch PVC pipe to the location for my soon to be build shed and plan on running #8 THWN to it. It is buried 18 inches deep. I picked 2 inch pvc because I also wanted to run cable and internet to the shed, but after reading a few post here, I am not sure I can run those in the same conduit as the wiring. So two parts:
1) can i run the cables in the same conduit

2) if not, can i run 1/2 conduit in the 2 inch pvc with the cable and internet in it?

Let me know! Thanks
 
Sponsored Links
  #2  
Old 06-11-12, 02:36 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,374
No, no and no. First of all, the conduit should have been buried with a minimum of 24 inches of cover but depending on exactly where the conduit runs 18 inches MAY be acceptable to the inspector. I do hope that you used PVC electrical conduit and not PVC water piping, they are not the same.

Second no is that no, you may not mix communication cables with power conductors in the same conduit. That one is an absolute so the third no is that no, you may not run a 1/2 inch conduit inside the 2 inch for communications cabling.

Added advice, use nothing less than 1 inch conduit for communication wiring such as telephone, cable TV, Ethernet, intercom, stereo speakers and the like. You may go to a minimum of 3/4 inch if you absolutely know all you are going to have is a single coaxial cable, (TV) single Ethernet (Internet) and single telephone via category 3 cable.
 
  #3  
Old 06-11-12, 03:37 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,664
The depth for non metallic conduit generally given in the forum is 18". The way I read table 300.5 of the 2008 NEC seems to support that.
Name:  Conduit-CableDepthb.jpg
Views: 4142
Size:  30.6 KB
 
  #4  
Old 06-11-12, 03:43 PM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
I was going to say something about the allowable 18” for specific conduit. Outside of that, I agree with furd.
 
  #5  
Old 06-11-12, 04:05 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,374
My fault for (a) going by codes several years removed from the present, and (b) most of the jobs I had any connection to being commercial rather than residential.

The last time I had any connection to an underground conduit job the inspector insisted upon 24 inch cover even though the only traffic in the area would have been foot and a riding lawnmower. This inspector questioned my use of IMC coming above ground (he said EMT was not allowable and I pointed out it was NOT EMT but IMC) but he passed the EMT the fence company used coming through the ground. I can't win!
 
  #6  
Old 06-12-12, 06:09 AM
Member
Thread Starter
Join Date: Jun 2012
Posts: 10
I thought this exception would be considered if i ran a seperate conduit in the 2 inch pipe for the cable & Cat 5:

NEC 800.133(A)(c) Exception No. 1 permits conductors of electric power and light to be run in the same raceway as communications conductors where the communications circuits are separated by a permanent barrier.

I would think the PVC provides the required separation.

I am not an electrician and do not claim to know much about anything, so please correct me if I am wrong!!!
 
  #7  
Old 06-12-12, 06:35 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,664
A lot easier to run two conduits.
 
  #8  
Old 06-12-12, 07:38 AM
Member
Thread Starter
Join Date: Jun 2012
Posts: 10
The issue is, I already filled in the 100ft long trench and returned the backhoe...and i live on a mountain, so there is more rocks than dirt...can not imagine digging by hand!
 
  #9  
Old 06-12-12, 08:48 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,374
Run it by your local inspector. I'm pretty sure it won't be approved but I've been wrong many times in my life.

I am curious how you plan on running the 1/2 inch conduit through the 2 inch. Do you not have any bends in the 2 inch? Maybe you can get 1/2 inch to slide through a 2 inch bend, I've never tried it. You will definitely have a problem if you have any L fittings and when you come to the end of the conduit run you WILL need to have complete separation from the power conductors. That means that you will almost certainly need a plastic J&P (junction and pull) box with the 1/2 inch continuing out the side of the box unbroken.

Also, you may have problems of 60 Hertz hum on the communication cables from such a long run parallel and in such close proximity to the power.
 
  #10  
Old 06-12-12, 10:36 AM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
The question I would raise is: Conduit fill. I can honestly tell you this. After doing a calculation (where 4-#8THWN was included), you do have room for 1/2 PVC Sch40 conduit. The problem: bends, and how to keep the cables seprated at the point of exit.
How far is the run?
 
  #11  
Old 06-12-12, 12:20 PM
Member
Thread Starter
Join Date: Jun 2012
Posts: 10
The run is 115ft in total, and is a straight line from house to shed...and i might run 3 #6 and a ground (#10) instead of the #8.

I do not plan on running telephone out to the shed, just internet and cable...this way the wife will have to come find me if she needs me!!!
 
  #12  
Old 06-12-12, 01:06 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,374
When you run the coax and Ethernet cables remember that they must have insulation suitable for wet locations. Any buried cable/conductor, even in conduit, is required to be so rated.
 
  #13  
Old 06-12-12, 01:16 PM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
You could install a very large in-ground junction box (Sized per box fill) at the end and start of the conduit. At each end and start you can let the 1/2 conduit continue without break—using listed conduit bodies. You would then splice the #6 inside the junctions, and continue it out with conduit. The 1/2 conduit would also extend from the junctions. Note: Regardless, you may have to upsize the terminal adapter to 3-3.5 inches to get the 1/2 PVC through it. It will work, but I have no idea how to explain it.
If you pay me 1 million dollars, I’ll try to draw it….LOL. Joking
 
  #14  
Old 06-12-12, 01:35 PM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
Note: You are cutting it somewhat close when up sizing to #6, but it will work. Your grounding conductor can be smaller. I would do a #8, but it can be smaller (#10)—depending on the load or size protection selected. Consider voltage drop, and size per your load calculations. Anyway you slice it, you will have to dig.
 
  #15  
Old 06-14-12, 10:34 AM
Member
Thread Starter
Join Date: Jun 2012
Posts: 10
I just want to make sure I am within code based on my post for the exception...

NEC 800.133(A)(c) Exception No. 1 permits conductors of electric power and light to be run in the same raceway as communications conductors where the communications circuits are separated by a permanent barrier.

Anyone else have any thoughts?

Also, any idea where i could get a cheap J&P box?
 

Last edited by asnyder1; 06-14-12 at 10:55 AM.
  #16  
Old 06-14-12, 02:58 PM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
See Post #9—consult your local authority (Electrical inspector). All you have to do is call them, and see what they say. Present it as a possible project. I personally don’t see a problem, unless you can’t meet conduit fill specifications. You would also have to make sure all electrical is installed per code. I believe your conduit inside a conduit does meet the intent of the code section you presented, but as I said, you would have to meet code from start to finish. The question will be how do you plan to keep the high voltage conductors from the Low voltage conductors. Below I offered a solution that will absolutely work!!!
 
  #17  
Old 06-14-12, 03:12 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,664
The issue is, I already filled in the 100ft long trench and returned the backhoe...and i live on a mountain, so there is more rocks than dirt...can not imagine digging by hand!
AFAIK there is no burial depth for communications cables in the NEC so dig out 6" of the trench you just filled and lay in your second conduit for the communication cable. How hard can it be to dig into a recently filled trench? A lot easier then your idea I'd wager rocks or no rocks.
 
  #18  
Old 06-14-12, 05:13 PM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
It was my understanding that the OP didn’t want to dig that long distance. But, if digging is an option, I would install conduit for the listed underground rated low voltage cable. If it was I, I would start digging the 100 feet, and say forget the hassle of my other option. Note: My option will work, but you will still have to dig-up each end, and install listed and rated in-ground junctions.
 
  #19  
Old 06-14-12, 05:34 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,664
I don't know about where the O/P is but here you could get it done for about $50 using "street corner" labor.

I think 6" would probably be enough and I can't see 6" in a freshly dug trench being that hard. to dig.
 
  #20  
Old 06-14-12, 05:56 PM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
I don't know about where the O/P is but here you could get it done for about $50 using "street corner" labor.

I think 6" would probably be enough and I can't see 6" in a freshly dug trench being that hard. to dig.
I agree!! The trenching method will be a lot cheaper!!!
 
  #21  
Old 06-15-12, 05:58 AM
Member
Thread Starter
Join Date: Jun 2012
Posts: 10
Ok...as much as I hate to say it, I think I have to agree with digging up 6 inches again and laying a new conduit...it will make the connections at the end much easier and J&P boxes are not cheap!

Guess that is why I have Saturdays off...lol.
 
  #22  
Old 06-15-12, 06:39 AM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,664
Guess that is why I have Saturdays off...lol.
No, that is why parents have kids.
 
  #23  
Old 06-15-12, 07:45 AM
Member
Thread Starter
Join Date: Jun 2012
Posts: 10
Haha...my oldest is in college...my middle will not be home...and my 11 month old does not dig fast enough!!!
 
  #24  
Old 06-15-12, 08:05 AM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
I would use conduit, regardless of the DB rating.
 
  #25  
Old 06-15-12, 09:37 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,374
I think you guys need to re-read Articles 300 and 800. My interpretation is that communications cable (and Ethernet, telephone, cable TV ARE communications) still require a minimum of 12 inches cover. Only landscape lighting and irrigation control is allowed a 6 inch cover AND that also requires a maximum of 30 volts.

I MAY be wrong. I only looked in the 2002 code and only skimmed the chapters.
 
  #26  
Old 06-15-12, 10:10 AM
SeaOn's Avatar
Member
Join Date: Dec 2011
Location: USA
Posts: 351
@ furd,
There is no cover requirements for the OP’s installation, unless the OP’s jurisdiction says otherwise. Normally nothings required on the property owners side. T.300.5 does not apply—even if conduit is required. Personally, i would go 24" inches or deeper if DB. No less than 6", and anything up to 24" would be in conduit.

But, if you have a code reference, please post, as I’m no guru on LV.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'