Feeding underground in block walls - Electrician Talk - Professional Electrical Contractors Forum

Marshall175 · 07-23-2009, 09:42 PM

The job I am on required quite a few outlets, both electrical and data, to be fed from underground, including a dozen or so in a free standing wall, with nothing to be fed from above...
what I did was saw a notch in the footing big enough to 90 up into the block. There was alot of sawing, but i don't see anyother way.
As this is my first job from start to finish, I was wondering if there is some other way to get up into to wall than sawing into the footing...or is this pretty standard?

william1978 · 07-23-2009, 09:46 PM

The slabs that I have roughed they run block up to floor level and before they poured those block cells full I would knock a hole in them with a hammer and stub up the pvc. Did a ton of schools like this. It always worked great.

william1978 · 07-23-2009, 09:47 PM

Do you have a picture of what you doing?

mattsilkwood · 07-23-2009, 09:59 PM

yea a pic would be great, i cant see where you would have to cut the footer.

MDShunk · 07-23-2009, 10:02 PM

Quote:

Originally Posted by mattsilkwood

yea a pic would be great, i cant see where you would have to cut the footer.

In northern climates, where the footer is way deep because of the frost line, we don't have this issue. In more southern areas, where the footer can be close to just below grade, notching the footer may, indeed, be necessary.

mattsilkwood · 07-23-2009, 10:11 PM

Quote:

Originally Posted by MDShunk

In northern climates, where the footer is way deep because of the frost line, we don't have this issue. In more southern areas, where the footer can be close to just below grade, notching the footer may, indeed, be necessary.

maybe im just not seeing it right but the footer will always be below ff so there is no need to notch the footer to get into the wall.

MDShunk · 07-23-2009, 10:14 PM

Quote:

Originally Posted by mattsilkwood

maybe im just not seeing it right but the footer will always be below ff so there is no need to notch the footer to get into the wall.

That sorta depends on the size of the sweep, depth of the pipe, and the depth of the footer.

480sparky · 07-23-2009, 10:16 PM

Check your A Sheets for a cross-section of the wall. Usually, the first course of CMUs is below the floor, so unless you're working with something larger than 1¼", you can get a bend into the lowest course and still not have to deal with the footings.

MDShunk · 07-23-2009, 10:17 PM

Quote:

Originally Posted by 480sparky

Check your A Sheets for a cross-section of the wall. Usually, the first course of CMUs is below the floor, so unless you're working with something larger than 1¼", you can get a bend into the lowest course and still not have to deal with the footings.

Unless the slab and the footer is a monolithic pour.

mattsilkwood · 07-23-2009, 10:25 PM

Quote:

Originally Posted by MDShunk

That sorta depends on the size of the sweep, depth of the pipe, and the depth of the footer.

yea but the op said rec and data so im thinking 1" tops.

480sparky · 07-23-2009, 10:31 PM

Quote:

Originally Posted by MDShunk

Unless the slab and the footer is a monolithic pour.

Then it's gonna get expensive.

It took me a while to find one, but here's a photo of what I mean:

Where the CMUs are cut will be below the floor, so you can pretty much cut or bust up the bottom course if this is what you have. The pipes on the upper right are resting on the poured floor in that area. Your A Sheets should have details of a wall cross section.

mattsilkwood · 07-23-2009, 10:34 PM

Quote:

Originally Posted by 480sparky

Then it's gonna get expensive.

It took me a while to find one, but here's a photo of what I mean:

Where the CMUs are cut will be below the floor, so you can pretty much cut or bust up the bottom course if this is what you have. The pipes on the upper right are resting on the poured floor in that area. Your A Sheets should have details of a wall cross section.

me to

Marshall175 · 07-24-2009, 05:46 AM

it would have been great if the first course was below grade, and in one area, it was. The entire rest of the building, though, the bottom of the first course was grade, hence, having to notch the footing....

yes, mostly 3/4" and 1".....occasionally a 1 1/2" for a tv

drsparky · 07-24-2009, 09:21 AM

Next time plan ahead and get conduit in place before the pour.

BDB · 07-24-2009, 10:56 AM

Yes, what drsparky said

Bob Badger · 07-24-2009, 11:12 AM

Quote:

Originally Posted by 480sparky

Check your A Sheets for a cross-section of the wall. Usually, the first course of CMUs is below the floor, so unless you're working with something larger than 1¼", you can get a bend into the lowest course and still not have to deal with the footings.

I have never done a building with CMUs that are below the slab. We would have to notch out the foundation wall (not the actual footing) to get inside the CMUs.