Underground Conduit Rules

[John McKissick]

Shortest path for new conduit is through the wall in front of the house to get to a distribution panel in the garage. Is there a way, per code, to come through the poured concrete underground then maybe 60 feet to garage? I have access inside the basement to drill hole right next to main panel on basement front wall.

Trying to avoid the visible conduit on the front of the house.

Option 2 is maybe 2x or more total the distance coming out the back of the house traditionally (about 30 feet) then a longer run underground.

In planning stages. Thinking 100 amp for now.

[Rod Sheridan]

Sure you can go through the foundation and underground to the garage.

You’ll have to follow local regulations for depth of burial...Rod

[Bruce Wrenn]

Water coming in around conduit? This could be a problem. Be sure to grout hole with hydraulic cement, not mortar mix. Grout from outside,not inside. If foundation is poured concrete, you could pack hole with lead wood and a use caulking iron to compress it.

[Charlie Velasquez]

Mmmm... Don’t have my code book with me.
But...
Because of its corrosive nature, any conduit in contact with concrete must be rated for concrete. PVC qualifies, but not all metal conduit does.
Article 300.5(something) talks about protection from earth movement. Coming directly from the foundation wall to the soil means any frost heave from the soil in Massachusetts would be a shear force wrt to your conduit and your conductors. Don’t know what your frost line is there. Coming out above grade, then going down allows for an expansion fitting to accommodate that.

Any underground conduit is a wet location. Temperature differences between the endpoints and length of the conduits will set up convection currents throughout the run. Moisture from the air outside the conduit will constantly migrate through the conduit. Anytime the temperature of the conduit 18” underground is lower than the dew point of the air outside the conduit that moisture will condense and slowly fill the conduit. If the conduit in your basement is the lowest spot...

How does your service entrance enter your house?

[Jim Becker]

Yes, you can do what you want to do. It has to be at code compliant depth as has been noted and you'll want/need to seal the penetration through the foundation with hydraulic cement, also as noted. You'll want to trench to proper depth, use appropriate sized PVC conduit for the intended pull and make sure there is a trace wire in the trench above the conduit so it can be located in the future. If you can get your pull tape in the conduit while you are assembling it, it will save time and effort when you do the pull of the actual conductors and ground.

[Ian Lerew]

PVC conduit needs to be buried 18”. You could come through just above grade and use an LB to turn the pipe down. You won’t have to worry about water this way and there won’t be much visible. Or you can come through below grade but like Bruce said make sure you seal it well. Hydraulic cement will work or closed cell spray foam.

[John McKissick]

Thanks all for your input and advice. Sounding a bit more complex and an error could have me mopping up water.

Plan B might be a strategically placed bush or just go the longer way.

[Robert Engel]

Is there such a thing as conduitaphobia?

[John McKissick]

Is there such a thing as conduitaphobia?

Technically hydrophobia, fear of water...lol

[Jim Becker]

Thanks all for your input and advice. Sounding a bit more complex and an error could have me mopping up water.

Plan B might be a strategically placed bush or just go the longer way.

It's not difficult to do what you want to do. You just need to follow the steps carefully at the house end of the connection when it's below grade. Hydraulic cement is simple and easy to use and it cures fast, too. But coming up above grade and going through the foundation with a pull box on the wall is "less risky" for water penetration for sure. And you can paint the exposed conduite to match the foundation. It will be barely visible by itself and probably would disappear entirely with some landscaping planning. The requirements for the trench remain the same either way.

[Julie Moriarty]

Shortest path for new conduit is through the wall in front of the house to get to a distribution panel in the garage. Is there a way, per code, to come through the poured concrete underground then maybe 60 feet to garage? I have access inside the basement to drill hole right next to main panel on basement front wall.

Trying to avoid the visible conduit on the front of the house.

Option 2 is maybe 2x or more total the distance coming out the back of the house traditionally (about 30 feet) then a longer run underground.

In planning stages. Thinking 100 amp for now.

Every installation I've ever done, that runs conduit from the house down into the ground, exits the house above the foundation wall. I've been on service calls where someone drilled through the foundation below grade and the called us to stop the water leaks.

One homeowner didn't want an exposed electrical fitting so I suggested he use Waterplug to see if that stops the leak. I was back a few weeks later changing the conduit run to exit the house above the foundation.

On commercial jobs I've worked, where they had to go through the foundation, there's always some feature there to channel the leaks when they happen. Or they just rely on maintenance crews to monitor it.

[John McKissick]

Thanks for your real world experience. The others have suitable "askeered" me away from underground penetration but I am so glad I asked and for the advice here

[Charlie Velasquez]

You didn’t mention how your service enters the house. If it is through a meter pedestal check the model # and look up the specs. Some allow for a secondary feeder to share the space. Most don’t but it is worth checking. If so, you may be able to exit above grade into the space of the pedestal, then branch off into its own trench after going down.

[John McKissick]

You didn’t mention how your service enters the house. If it is through a meter pedestal check the model # and look up the specs. Some allow for a secondary feeder to share the space. Most don’t but it is worth checking. If so, you may be able to exit above grade into the space of the pedestal, then branch off into its own trench after going down.

The service is a bit untraditional. Technically a condo with meter/mains on front of house on neighbors side. Transformer 200 feet away with underground cable feeding both meters above grade. My line comes in through wall into their basement and routes into mine inside to my panel with no main breaker in it. Breaker is outside with meter.

Wife is warming up to exposed conduit coming through the wood/siding with a pullbox then going gopher-mode underground to garage/shop.

[Wayne Cannon]

I don't know the scope of the requirement, but here the contractor poured several inches of gravel in the trench atop the PVC conduit plus a colored ribbon so future backhoe operator gets some warning before cutting into the conduit.