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Discussion Starter · #1 ·
A long story short; I am having a shop built and was advised to have a 2.5" "electrical tube" installed during the concrete slab pour. My assumption is that this is just a plastic-based conduit tubing that will allow for future electrical service to reach the shop by passing through the concrete for a cleaner install.

My question is:

What am I looking for specifically regarding the purchase of this 2.5" OD tubing? Any help is appreciated.

Thanks!
 

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Discussion Starter · #3 ·
Ok, so there is no concrete-specific electrical conduit required for this? Under no circumstance would I use plumbing pipe. The concrete contractor just asked that I purchase the conduit prior to him pouring the slab, and he'll install it.

We have already specified where the panel will be located too as well, so the conduit will just need to be set directly under that spot, correct?

Thank you for the quick response by-the-way as well.
 

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Word of advice, tape up both open ends of the conduit. Also, make sure the joints are cleaned and glued and that the conduit is supported and secure. Depending on the depth of the floor, you may want to go with schedule 80 pvc. Concrete is heavy and there will be people walking over it during the pour. May even want to consider two of them or one larger than 2 and 1/2" Once the concrete is poured and set, there is no adding another if that one is broken or has concrete in it. I've seen both.
 

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Assuming your electric will be coming in under ground, the elbow should be set at the electric bury depth. Then run a horizontal out far enough to clear the slab/footer. Cap the ends and bury. Map out where the end is, you or some one is going to need to find it when it comes time to run the electric.


Running any other utilities? Water, sewer or cable or internet?
Might consider in putting additional riser(s)


I put 2 in my own.
 

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Discussion Starter · #9 ·
1. Yes, the electric will be underground from the house to the shop.
2. No other utilities.

My thought regarding the "dirt side" was to purchase enough of the conduit to build a "U" shape pointing vertical again so that the future electrician could easily find outdoor side, but your line of thinking has me rethinking that idea. By your idea, I would be building a long "L" shape with the short leg facing upward into the shop, through the slab, which makes perfect sense. I am not opposed to putting in two legs as suggested as well for future expansion.

To anyone wondering why this isn't being handled by one GC/electrician; There are two GCs during my build of the house and shop at different times. With the virus slowdown, I am unsure when either will be completed, and am getting as much done as possible in the interim.
 

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What am I looking for specifically regarding the purchase of this 2.5" OD tubing? Any help is appreciated.
Conduit is specified by ID, not OD. They are trade sizes (not exact)

2.5 inch PVC has an ID of 2.469 and an OD of 2.875 (schedule 40)

In schedule 80 they maintain the same outer diameter but use a thicker wall. That reduces the ID to 2.323.

Who is buying the sweeps (bends) and what radius was specified ?

You either need a specific list from the contractor of what to buy and how many, or he needs to order the stuff.

You don't want to be responsible for too small of a conduit or too tight of a turn when it comes time to pull wire.
 

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Discussion Starter · #13 ·
Conduit is specified by ID, not OD. They are trade sizes (not exact)

2.5 inch PVC has an ID of 2.469 and an OD of 2.875 (schedule 40)

In schedule 80 they maintain the same outer diameter but use a thicker wall. That reduces the ID to 2.323.
Thank you for this information. Duly noted.

Who is buying the sweeps (bends) and what radius was specified ?
I was told to purchase the smoothest bend possible in 2.5" (now I know it's ID vs OD, thank you)

You don't want to be responsible for too small of a conduit or too tight of a turn when it comes time to pull wire.
As noted above, I am dealing with two separate GCs on one build site, which is making me the go-between because they aren't talking to each other. The GC with the electrical contractor advised me to purchase the items above. I just want to make the future electrician's life that much easier knowing I bought the correct stuff.

Thank you for the detailed information
 

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Ufer Ground! Ufer Ground! Ufer Ground! Be very insistent on that.

This is far-and-away the best grounding rod design. Not for neatness but because it is a fantastic ground! It's easy for the concrete contractor to include. It is also easy to forget to include.

The type of pipe is easy: If in doubt, Sched 80 PVC because that provides protection from physical damage (Sched 40 does not). It should certainly be sched 80 from the panel down to burial depth (which had better be 18" of cover).

Keep in mind that 2-1/2" is a trade size. That is based on inside diameter, but is *based* on outside diameter, since that is the critical dimension for mating to fittings. So you have silliness like 3/4" pipe OD being 1.050". Expect 2-1/2" trade size pipe to be about 3" OD.
 

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I would use Schedule 80 PVC conduit.
 

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My thought regarding the "dirt side" was to purchase enough of the conduit to build a "U" shape pointing vertical again so that the future electrician could easily find outdoor side, but your line of thinking has me rethinking that idea. By your idea, I would be building a long "L" shape with the short leg facing upward into the shop, through the slab, which makes perfect sense. I am not opposed to putting in two legs as suggested as well for future expansion.

You could also wrap a tracer wire on the end of your soon to be buried conduit, and keep it vertical as you back fill. Probably help some one find the buried end.
 

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Typically only the power companies call for a long sweep elbow. The premade 90s all have the same radius.
 

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One other thing.
Just make sure the conduit is deep enough where it exits the concrete and continues into the ground. Although some transition is usual it needs to be 18" by code.....your local code may vary.
 
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