Gas & electrical conduit in same trench?

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Old 07-06-17, 06:31 PM
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Gas & electrical conduit in same trench?

Hi all - Years ago my late dad had a Generac emergency generator installed. He said it was done by professionals. Well, according my code enforcement officer, he says it's too close the structure (house), code says a minimum of 5 feet and I'm lucky if it's a foot away from the house. Well, my younger brother and I are in the beginning stages of moving it to 5 feet from the house. In order to accomplish this I need to bury the gas (LP) line and electrical conduit. I'm wondering if any of you fine folks know if it is permissible to have both the gas line and electrical conduit in the same trench? I'll be contacting my gas company to inquire what to use for gas line and have them make the final connections. As usual, thanks in advance for the help. Roger
 
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Old 07-06-17, 08:02 PM
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Maybe the code wasn't 5' at the time of installation. Why is an inspector involved now? Is there vinyl siding on the house?
 
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Old 07-06-17, 08:11 PM
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Generators are a touchy thing. The code is 5' if the generator housing IS NOT fire rated. Most Generacs are fire rated meaning they can be installed 18" from a combustible surface. With the exact model number.... the installation instructions can be checked for clearances.

This is from the NFPA and pertains to Generac generators.
generator-installation.pdf

However.... remember.... the code official is always right.
 
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Old 07-07-17, 03:28 AM
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pjmax - I showed the code official that the installation manual says a distance of 3 feet from the house but his point is local codes (5 feet) supersedes the installation manual. So, I have no choice but to follow my code official. He's always treated me well and I want it keep it that way. Plus, I want to stay on his good side. Anyone know the question of gas line and electrical conduit in the same trench? Do you think the gas company will have the answer for me? thanks
 
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Old 07-07-17, 04:31 AM
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Natural gas and electric are run in the same trench all the time by utilities, and in some cases there isn't even any significant separation. You're pulling your LP from the top of the tank, right? So this is gaseous propane rather than liquid in the underground line? I assume so.

Since you never did answer why the code official was out there, and it seems the whole point of the project is just to stay on his good side, why not just call him up and ask what he wants to see?? Especially if this guy is wandering through people's backyards with a ruler looking for decades-old noncompliance? Maybe 6" radial separation is required in your area. Maybe 12". Maybe none.

Keep in mind that once you backfill, there is no trench! What I'm getting at is: If there is a required radial separation, you can accomplish it vertically. It's the "same trench" as far as your sore arms are concerned, but once filled, that trench no longer exists, and the second run can be placed above the first run.
 
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Old 07-07-17, 07:48 AM
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core - You're right, I did not address the question as to why he was there. I had pulled a permit for some electrical work I had performed in the house. When he arrived to inspect the rough electrical work, I was not inside the house, I was in the back where the generator is placed. It was then that he noticed the generator being close to the house. One thing I need to mention is the guy is a neighbor who needs to drive by my house every time he drives to work, so one cannot hide anything from him. He doesn't snoop, he only stops by why I have questions regarding permitted work.

Your assumption it being LP is correct. It was included in my original post.

I received word from the code official, he answered 2 questions for me; 1) He says the LP gas line needs to be in a trench by itself at a minimum of 12 inches down and the electrical needs it own trench with a 3 foot separation at a minimum 12 inches deep. 2) He said due to this being an extension of previous work, a permit is not needed. I will not argue with him. Now, a phone call to the gas company to see what they will require regarding gas line under ground. Roger
 
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Old 07-07-17, 08:32 AM
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He said only 12" deep for the electrical conduit? Interesting. I'd still put it at 18" if I was going to be out there digging anyway. He may have just had a senior moment if you caught him away from his reference materials.

Your assumption it being LP is correct. It was included in my original post.
Yes you said it was LP, but not if the Liquified Petroleum was still going to be "liquified" in the underground line. Yeah, I know, why anyone would run a wet leg for this is beyond me, but hey stranger things have been done by homeowners. It does make a big difference when utilities bury them in the same trench. Why that is, I do not know.

I wonder how they expect folks to keep 3 feet separation as the runs rise to the surface and get close to the device.
 
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Old 07-07-17, 10:58 PM
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Since the electrical access and the gas connection are at two different locations..... we just dig two trenches.

Are you going to use CSST for the gas line ?
When you say gas company.... you mean the company that fills your tank ?
 
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Old 07-08-17, 04:48 AM
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pjmax; The gas company to whom I refer is the one who owns the gas tank, it's the same company who fills the tank for me. I will use what the gas company requires. I know that if I install anything other than what they want, they will not make the final connections for me. Roger
 
 

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