Trench sharing

[Dart53]

Can I put electrical conduits in the same trench as a sewer line? Shortly I will be connecting to recently available town sewer. At the same time I am planning to install a 60 amp subpanel in my attached garage and a standby generator just outside. The cable for the subpanel and generator will be underground in PVC conduit running in the same direction as the sewer line. So I was thinking of utilizing the same trench for all three if allowed by code.

 

[sands35]

You will need to check with your inspector's office. This is one of those things that will fall between NEC and other codes.

For what it's worth, the local AHJ let me put a gas line and two 1.5" conduits in the same trench. They just wanted ~4" of cover over the gas line and the PVC to be down 18". I ended up digging about a 26-30" deep trench - deeper than required for a gas line, but made the inspection simple.

Who is accountable for the sewer line? You or the sewer Co? If it's the Sewer company, then they might want a clear trench for potential maintenance.

 

[matt151617]

How deep is the sewer line going to be? Since it has to be sloped, it'll probably start fairly shallow at the house and get deeper and deeper. The electrical line will have to be a minimum of 18" deep from start to finish. It may be easier to dig one 18" level trench for the 2 electrical lines and one sloped trench for the sewer line.

 

[CNGsaves]

Even if it's allowed, do NOT do it.

Whole lot different putting NG (ie with yellow polyethlene plastic) buried in same trench with electrical conduit, as they likely will never need service. Proper spacing of these likely would be allowed by local code.

Sewer lines generally much deeper in ground, and IF they ever need service, the backhoe digging a giant trench is the LAST thing you want anywhere near electrical or NG buried lines. Tree roots seek out water, and could create broken sewer line within "short" number of years in overall scheme of owning a house. Say 10 yrs from now maple tree has roots grown into sewer line and it needs dug up??

Why save a few bucks and create likely future problems??

 

[sands35]

Sewer needs to be below the frost line the whole way out. In Massachusetts (OP ?), that is probably 42". Likely it's at the bottom of the basement wall if not under the footers.

 

[ddawg16]

Even if it's allowed, do NOT do it.

Whole lot different putting NG (ie with yellow polyethlene plastic) buried in same trench with electrical conduit, as they likely will never need service. Proper spacing of these likely would be allowed by local code.

Sewer lines generally much deeper in ground, and IF they ever need service, the backhoe digging a giant trench is the LAST thing you want anywhere near electrical or NG buried lines. Tree roots seek out water, and could create broken sewer line within "short" number of years in overall scheme of owning a house. Say 10 yrs from now maple tree has roots grown into sewer line and it needs dug up??

Why save a few bucks and create likely future problems??

That is the main reason right there.....while there may not be a code preventing it....at some point it will have to be worked on....it's no fun having to redo your electrical and/or gas line.

If you work on cars...I'm sure you have said a few cuss words to the guy who decided to put an engine part in front of another part...don't you just like pulling the front of your engine off just to get to a small part?

 

[Dart53]

We just moved into this house 2 months ago. As the homeowner I am responsible for the sewer line. The waste pipe exits the house 32" below the top of foundation which surprised me a little. I have the same reservations about disturbing one or the other if repairs have to be made. Just thinking I could save a few $$ (or my back). I'm going to take everyone's advice and keep electrical and sewer lines apart. Thanks to all who responded.

 

[Sureshot]

Do yourself a favor and buy some of the yellow or red rolls of Danger or caution tale and put it about 6" above your sewer and power installs so if you ever dig it up you have "marker". Also take pics of the open trench with tape measure or distances visible etc.

When I buried my stuff which is stacked in a deep trench I also ran airline, phone, and ethernet. You could also run a spare 1 1/4 hose to fish through in the future. Real cheap to do now.

 

[ddawg16]

Do yourself a favor and buy some of the yellow or red rolls of Danger or caution tale and put it about 6" above your sewer and power installs so if you ever dig it up you have "marker". Also take pics of the open trench with tape measure or distances visible etc.

When I buried my stuff which is stacked in a deep trench I also ran airline, phone, and ethernet. You could also run a spare 1 1/4 hose to fish through in the future. Real cheap to do now.

That is some good advice and ideas....

big yes on the pictures....I have a **** load of pics on my projects and you would not believe how often I go back to review stuff....

And yes on the extra PVC conduit....it's really cheap right now....compared to doing it later....

 

[Gary S]

Sewer lines generally much deeper in ground, and IF they ever need service, the backhoe digging a giant trench is the LAST thing you want anywhere near electrical or NG buried lines.

I'd make one change...........................Remove the IF and replace with WHEN.

 

[matt151617]

I'd make one change...........................Remove the IF and replace with WHEN.

What about if there's no trees or large plants nearby? My parents house has the original cast iron sewer lines from whenever indoor plumbing became available (30s or 40s probably).

 

[zmaxmotorsports]

Id seperate them myself,at some point it seems like a sewer will need to be worked on it would make things easier to deal with.