# Am I Crazy?? PVC Question



## A Good Electrician (May 29, 2011)

Hey Guys. I'm out here in California and I had an Issue today that was very embarrassing. My understanding Is that for 1" PVC Underground you must have a strap within 3' of a Box, termination, Etc and then supports every 3'. Come to find out after we set up 300' of trench this way, that's only if we are concrete encased? this particular trench is going to be back filled with sand and then gravel. do we no longer have to support in this scenario? Help!! 
And I get it, we're buried in the ground. What do we need support for, but i'm just trying to keep to code, I thought?


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## 3xdad (Jan 25, 2011)

Am i understanding that you supported it every 3' in the ditch?


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## 99cents (Aug 20, 2012)

Throw it in the trench. Cover it up. Done.

If this was a time and material job, you scored  .


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## A Good Electrician (May 29, 2011)

@3XDad, Yes. O.K. I can already tell I'm super wrong. But what's up with:

352.30 Securing and Supporting
PVC conduit shall be installed as a complete system as provided in 300.18 and shall be fastened so that movement from thermal expansion or contraction is permitted. PVC conduit shall be securely fastened and supported in accordance with 352.30(A) and (B).


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## A Good Electrician (May 29, 2011)

@99cents, I wish That's definitely why I'm frustrated. Waisted time and money today.


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## Dennis Alwon (May 9, 2009)

A Good Electrician said:


> @3XDad, Yes. O.K. I can already tell I'm super wrong. But what's up with:
> 
> 352.30 Securing and Supporting
> PVC conduit shall be installed as a complete system as provided in 300.18 and shall be fastened so that movement from thermal expansion or contraction is permitted. PVC conduit shall be securely fastened and supported in accordance with 352.30(A) and (B).


The PVC needs support above ground-- in the trench there is no need. When you come out of the ground you may need expansion joints straps etc.


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## 3xdad (Jan 25, 2011)

You are correct in that 1" is supported at 3', but not UG. And concrete only changes your depth requirements in 300.5 or 300.50.(2011)

i'm curious how you did dat.


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## 99cents (Aug 20, 2012)

A Good Electrician said:


> @99cents, I wish That's definitely why I'm frustrated. Waisted time and money today.


Ah, it's all part of the learning process. Could have been worse. Can you imagine if it was supposed to be concrete encased and you didn't raise it? That could have been a chit storm  .


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## A Good Electrician (May 29, 2011)

O.K. Guys. I'm convinced I made a mistake but if the Code gives a requirement, they usually indicate when there are exceptions or "it's different in this or that case". Can anyone tell me when/where in the code it say's, "No strapping requirements underground."
I have done large underground jobs in the past and I assumed the strapping we did then had more to do with keeping the Conduit from "floating" in the slurry. Those where 4" to 6" conduits. When I read up about the 1" i was surprised at the 3' but just assumed it was because it's lighter and could "float" more easily. Again, this is when I was under the impression that we were pouring slurry.


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## A Good Electrician (May 29, 2011)

@99cents. You're right. It's my least favorite way of learning but it always does the trick.


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## backstay (Feb 3, 2011)

A Good Electrician said:


> O.K. Guys. I'm convinced I made a mistake but if the Code gives a requirement, they usually indicate when there are exceptions or "it's different in this or that case". Can anyone tell me when/where in the code it say's, "No strapping requirements underground."
> I have done large underground jobs in the past and I assumed the strapping we did then had more to do with keeping the Conduit from "floating" in the slurry. Those where 4" to 6" conduits. When I read up about the 1" i was surprised at the 3' but just assumed it was because it's lighter and could "float" more easily. Again, this is when I was under the impression that we were pouring slurry.


Wouldn't the ground "support" it? If you are going to support it, what would you use, sand screws?


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## A Good Electrician (May 29, 2011)

Curious about how I did the supports?


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## Bugz11B (May 12, 2013)

Wait.... What?? How loud did the inspector laugh??


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## A Good Electrician (May 29, 2011)

@Bugz11B

No inspection till' Friday. It was brought up when the General informed us that the run would not be concrete incased.


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## backstay (Feb 3, 2011)

A Good Electrician said:


> Curious about how I did the supports?


Pictures would be nice.


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## Hmacanada (Jan 16, 2014)

I'm sorry for this but .... Ha,ha,ha,ha,ha,ha,ha,ha,ha,ha,ha.
Seriously you are never going to live this down with your co-workers.
BUT ..... With inspectors you never know what they might want!



Sent from my iPhone using electriciantalk.com


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## Ultrafault (Dec 16, 2012)

Snap some pics. This thread is the best.


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## ponyboy (Nov 18, 2012)

I can't even wrap my brain around it. And I'm wicked smart.


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## FlyingSparks (Dec 10, 2012)

You'll be the butt of the jokes for a while that's for sure. I've done dumb things as well, and everyone else on this forum has too. Chuckle and move along.


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## Carultch (May 14, 2013)

99cents said:


> Throw it in the trench. Cover it up. Done.
> 
> If this was a time and material job, you scored  .



By doing that, you are not only supporting it every 3', but you are also supporting it every 1', and every 1", and every 1 mil, and every 1 micron.

If it is in a backfilled trench, it is supported continuously, and doesn't need any straps.


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## Big John (May 23, 2010)

The only thing I want to know is that if you and _Bad Electrician _ever meet and shake hands, will it annihilate the world?


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## hardworkingstiff (Jan 22, 2007)

A Good Electrician said:


> O.K. Guys. I'm convinced I made a mistake but if the Code gives a requirement, they usually indicate when there are exceptions or "it's different in this or that case". Can anyone tell me when/where in the code it say's, "No strapping requirements underground."


I doesn't. The code says it must be "supported", only "secured" within 3' of a box. The ground supports the conduit, no?

If the PVC is supported while in a trench (assuming the support will raise it above the bottom of the trench) then you would get a wave action in the conduit when you backfill (the backfill pushing the conduit down between the supports) and all those ups/downs should be counted in the 360 degrees of bends limitations.

Just sayin.


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## 8V71 (Dec 23, 2011)

Big John said:


> The only thing I want to know is that if you and _Bad Electrician _ever meet and shake hands, will it annihilate the world?


And if ugly electrician just happened to show up for a 3-way, the entire universe would be in trouble. Or would it just take out all of the spaghetti factories? :laughing:


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## robnj772 (Jan 15, 2008)

Bugz11B said:


> Wait.... What?? How loud did the inspector laugh??


I think I heard him laugh from here.


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## Laroc3 (Jul 20, 2013)

Trenched in 320' of 2" PVC the other day, just laid it in the tench. Done In about an hour.


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## pete87 (Oct 22, 2012)

The only support in a trench I have ever used is those plastic spacers for concrete encased banks of Conduit .





Pete


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## cabletie (Feb 12, 2011)

The most bizarre spec I ever had to comply with was supporting underground conduits. The engineer wanted the conduit that were run under the building concrete encased and supported from the slab above. We had to support the conduits on a unistrut rack set on bricks. We bent the rod over after the trench was poured, and it was tie wired to the rebar in the slab. Apparently this is a more common method for waste pipe with sandy soil and a high water table, at least the plumber said this was not the first time he had to do it. He also did not have to concrete encase.

Other than that I have never supported underground conduit with nothing other than dirt.


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## KneePads (Mar 5, 2014)

I once had to install PVC in a 14" thick post tension floor. Most of the conduits were for kitchen island feeds which were easy but I had eight apartment units that had exposed ceilings and had to rough in lighting boxes and power conduits in the PT deck. This would have been fairly simple but the engineer cam out and told us that our conduits had to all be in the middle of the slab. So we had to elevate and support our conduit at 7" off the bottom form. We used the stands that the rebar guys used to elevate. It was a huge pain in the a$$. When the inspector came out he asked me why we elevated the conduit and just chuckled and said good luck. The day of the pour the concrete guys broke 4 conduits before the concrete even started to pour. Luckily I made the architect sign off liability, I told her I could almost guarantee that we are going to loose a conduit when concrete gets poured and will have to run wiremold. 4 of the units ended up with wiremold.


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