The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Temporarily feeding a panel...
by Potseal
11 minutes 57 seconds ago
Locked rotor, no burnout
by jraef
22 minutes 31 seconds ago
Massive power outage South Australia
by Meadow
Today at 06:46 AM
short circuit??
by Meadow
Today at 06:43 AM
Norwegian power?
by Meadow
Today at 06:36 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
HotLine1 13
sparky 10
gfretwell 8
sparky66wv 8
Vlado 6
Who's Online
3 registered (Potseal, gfretwell, jraef), 111 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#170822 - 11/12/07 05:30 PM ditch depth under "pavers"??
sparkync Offline
Member

Registered: 10/17/02
Posts: 811
Loc: NC
I know the depth under cement is normally 4 " with RNC, but just wondering if the depth could be the same with paving stones? The job I'm on is having pavers put down around their pool ( proffesionally ) with gravel etc. and the installer said you would have to drill the pavers out. As far as I know the code don't specify this as an option, but what do you think an inspector might say about this?? I'll probably go the 12" rule for circuits that are GFI protected and rated 20 amps or less, but in this case it would be NICE to have it the same as concrete. I hate to bug the inspectors any more than I have to. I've called on them quiet a bit lately. Thanks, Steve

Top
2014 / 2011 NEC & Related Books and Study Guides
#170826 - 11/12/07 06:39 PM Re: ditch depth under "pavers"?? [Re: sparkync]
gfretwell Online   content

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
300.5 uses the words "concrete" and "slab". That can't be confused with pavers. I won't say your AHJ won't go along but I am not sure how.
RNC is only 6" anyway so he might consider 2" of paver as being part of the 6" cover. Keep it 5' away from the water if at all possible.
_________________________
Greg Fretwell

Top
#170831 - 11/13/07 07:18 AM Re: ditch depth under "pavers"?? [Re: gfretwell]
Zapped Offline
Member

Registered: 10/01/02
Posts: 481
Loc: Huntington Beach, CA, USA
I agree with Greg on 300.5, as concrete is more of a continuious material, and more "permenant" in a sense.

However, I have SEEN RNC laid to about 6" below paver bottoms and also have seen it pass inspection. As far as "drilling out" the pavers, I'd have to question the logic in this, if I'm getting what you mean.

If acheiving a 12" depth is an issue, you might have to bite the bullet and inquire with the AHJ as to how he inturprets 300.5. A screw up here could cause a re-do, and nobody wants to work for free!

Good Luck!

Top
#170834 - 11/13/07 08:26 AM Re: ditch depth under "pavers"?? [Re: Zapped]
gfretwell Online   content

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
Using RNC I am not sure when it ever needs to be more than 6" down if you aren't going under a road, runway or parking lot.
Look at 680.10 for a more specific answer. You still see 6" and I could see how an AHJ might measure from the top of the paver.
_________________________
Greg Fretwell

Top
#170853 - 11/13/07 05:14 PM Re: ditch depth under "pavers"?? [Re: gfretwell]
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
Greg- You guys are talking about RNC not RMC Double check your comments. (I think)
_________________________
George Little

Top
#170856 - 11/13/07 05:35 PM Re: ditch depth under "pavers"?? [Re: George Little]
gfretwell Online   content

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I typed it several times and still never realized we weren't talking about "rigid".
Sorry for the confusion.
I guess that is why I used to always say RNMC for the plastic.
_________________________
Greg Fretwell

Top
#170860 - 11/13/07 05:55 PM Re: ditch depth under "pavers"?? [Re: gfretwell]
George Little Offline
Member

Registered: 01/18/04
Posts: 1492
Loc: Michigan USA
I'll let it slide this time Greg but only this time \:\(
_________________________
George Little

Top
#170874 - 11/13/07 07:01 PM Re: ditch depth under "pavers"?? [Re: George Little]
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5299
Loc: Blue Collar Country
I really hate to sound like a broken record .... but does not Section 90 of the NEC plainly state "this is not a design manual?"

So, how deep should the pipe be buried? Well, as deep as it needs to be when it exits from the protection of the slab, would be a good start. Or, do you plan on changing the trench depth every time you have a change of the surface material? Lots of luck sanding the angled parts.

Or, consider this: what's a likely cause for the pipe being damaged? Besides the gardener using his shovel to look for irrigation lines ... how about frost heave? I don't care how well the pavers are laid .... give them a few frost cycles, and they'll be all over the place. Maybe the angled pavers will now even act like scissors on your pipe.

Whatever depth you decide upon, make it an honest depth. That is, to the top of the pipe, after it's properly bedded in sand - and NOT the rough depth of the trench! This means a 6" burial depth starts off with a 12" ditch.

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals