Duct into concrete building

FaradayFF

Senior Member
Greetings,

What is the typical recommended method of transitioning from underground duct bank into existing building with 12" brick wall? I am thinking the duct bank would stub up into exterior junction box with conduits going from this JB, through the wall, into the interior junction box. Both JBs would be wall mounted and at the same elevation relative to the grade.

If anyone can recommend a good literature on this topic that covers industry practices, that would be much appreciated.

Thanks,
EE
 

infinity

Moderator
Staff member
What is the reason that you're thinking of a junction box on the outside and not bringing the conduits directly through the wall?
 

FaradayFF

Senior Member
What is the reason that you're thinking of a junction box on the outside and not bringing the conduits directly through the wall?
What would be some advantages of bringing the conduits directly through the wall apart from this being a seemingly simpler install?

Thanks,
EE
 

infinity

Moderator
Staff member
Not having the box on the outside would possibly make it easier to pull in the conductors. If a box is need to transition we would probably come into the box on the inside to eliminate the need for a more expensive outdoor box.
 

Cow

Senior Member
Cut concrete floor out inside near exterior wall. Undermine foundation and stub conduits up inside of building. Encase duct bank in flowable fill/CDF/concrete to meet compaction requirements under foundation.
 

PaulMmn

Senior Member
re: Cow's comment-- how deep are the conduits compared to the basement floor? Would the conduits come thru the wall or up from the floor?
 

FaradayFF

Senior Member
re: Cow's comment-- how deep are the conduits compared to the basement floor? Would the conduits come thru the wall or up from the floor?
The top of duct bank is below the basement floor. I don't think at this point it is feasible to stub conduits up inside the building. The conduits need to come thru the wall.
 
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