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boat73 11-20-2011 01:40 PM

Concrete Footing 2" underground, what to do?
Hello all. I am running electricity to an out building thta is approx 70 years old and have hit a glitch. The concrete footing which is 2" underground comes out from the building about a foot and is prob 8" thick. The attached photo isn't great but, might help. Would it be legal to bring the sched 40 PVC out of the ground at the edge of the concrete and then run across the top to the building at ground level for that last foot. Any other suggestions would be greatly appreciated.

Bud Cline 11-20-2011 01:42 PM

The concrete footing is...

two inches underground, or,
two feet underground?

gregzoll 11-20-2011 02:20 PM

Photo, what photo. Oh, the mystery thickens.

boat73 11-20-2011 02:42 PM

1 Attachment(s)
1. thanks for the quick replies

2. it is 2 inches underground, extends a foot from the building and, is about 8 inches thick.

3. hmmm, the picture was there honest. i have attached it this time.

Milwaukeetool 11-20-2011 02:56 PM

I believe it is a 2" slab that the out building is built on rather than a footing.

a7ecorsair 11-20-2011 02:57 PM

I don't see in the picture where the footing extends beyond the wall a foot. It looks flush to me

gregzoll 11-20-2011 03:13 PM

boat73, you are going to have to pull the dirt off around the structure to see how far the material runs along the length. It could just be block, but you will not know, until you do more excavating.

JoJo-Arch 11-20-2011 03:31 PM

Why not line up the trench with a corresponding point on the inside of the shed and drill a 2'' hole right through the concrete. It is most likely less than 8'' thick anyway on the inside of the wall. Then extend the trench and dig under the projecting concrete edge beam. If you push a broom handle or similar piece of wood, you will see where the bottom of the hole you drilled is. Then run the 40mm conduit in the trench and up through concrete floor on the inside of the wall. Continue the conduit vertically to serve a power point or sub switchboard. Note the actual wiring and connections must be carried out by a qualified and licensed electrician. That way, the conduit is fully protected, out of site and neatly fixed to the wall on the inside. There are codes about the depth of trench for electric conduit, the protection of the conduit with concrete pavers and marking of the conduit route with special conductive tape, so you may need to just dig the trench and leave the rest to the electrician.

Cheers from the big Oz.

JoJo-Arch 11-20-2011 03:40 PM

I would also add that drilling a 2'' hole with today's drills is straight forward. I purchased a hammer-rotary drill for $50 plus a set of diamond tipped core bits 1'',2'',3'' and 4'' for $40 from our supermarket chain Aldis and these bits will drill to 10''. I know it's an el cheapo, but so far its been fine for drilling a small number of large holes in concrete. That's all I expected it to do.
Cheers, from Oz

boat73 11-20-2011 03:58 PM

1 Attachment(s)
Thanks all, i know that picture is hard to see all the depth. I marked this one to try and make it easier to see all the dimensions. I have drilled concrete before but was hoping there would be a better code approved method. The concrete has a lot of rocks in it so I wasn't sure if that might make it harder to drill. I suppose I could just use a hammer drill to chissel ot a channel if i had to.

jimmy21 11-20-2011 04:36 PM

39 Attachment(s)
why not just come up on the outside and LB into the shed?

JoJo-Arch 11-20-2011 05:05 PM

Yep! as I said, the code will not let you have exposed conduit externally unless is properly protected. Rember when the weeds grow and you forget about the conduit down the track, the first time you dig the weeds according to Murhy's law, will be when you don't need drugs to see the light.
Cheers from an architect that is trying to save your life. :whistling2:.

boat73 11-20-2011 05:06 PM

I am using an LB but, does the LB need to be right at the wall or can it be 6 inches out with a section of PVC between it and the house?

jimmy21 11-20-2011 10:31 PM

39 Attachment(s)
Don't do that, just heat the pvc and it will bend like a wet noodle. Not hard at all. Also, bring the LB up above weed height, so you don't forget its there. I don't know about other areas, but around here, the AHJ does not consider this application exposed to physical damage.

Jim Port 11-21-2011 07:08 AM

I would consider that area subject to damage from lawn mowers and string trimmers.

A sweeping offset could be used to get over the footing.

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