I'm bidding on a project that requires the use of "T" fittings at low points in long undergroung conduit runs, between Junction Boxes, to provide drainage. We are using 2" pvc Sch 40 for Power and 4" PVC Multiduct for communications. These " T " fittings will be buried underground all over the place if they are used. Does the NEC permit this? Is there an underground conduit drainage fitting that is approved for the purpose of drainage in electrical and communications conduits?
T fittings for drainage In underground PVC
- Thread starter denlong
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jimwalker
Senior Member
- Location
- TAMPA FLORIDA
Re: T fittings for drainage In underground PVC
I would think they would let water in not keep it out.
I would think they would let water in not keep it out.
Re: T fittings for drainage In underground PVC
I think this is an excellent idea, and the first time I saw it was 1979 for remote buildings at Nokomis Elementary School in Sarasota county FL.
The EE had us dig a 3' x 3' hole at the middle of the run, which by design, was the low point of the run between the buildings.
At this point we filled this hole with washed stone and created a "French Drain", we then installed a "T" fitting at this point which provided an outlet for the condensation, this is actually a great way to provide "Drainage" for a raceway.
Roger
I think this is an excellent idea, and the first time I saw it was 1979 for remote buildings at Nokomis Elementary School in Sarasota county FL.
The EE had us dig a 3' x 3' hole at the middle of the run, which by design, was the low point of the run between the buildings.
At this point we filled this hole with washed stone and created a "French Drain", we then installed a "T" fitting at this point which provided an outlet for the condensation, this is actually a great way to provide "Drainage" for a raceway.
Roger
charlie
Senior Member
- Location
- Indianapolis
Re: T fittings for drainage In underground PVC
Personally, I don't like it. In all conduit runs that are underground, inside the conduit is considered a wet location. You use wire that is listed for a wet location, where is the problem?
Personally, I don't like it. In all conduit runs that are underground, inside the conduit is considered a wet location. You use wire that is listed for a wet location, where is the problem?
charlie
Senior Member
- Location
- Indianapolis
Re: T fittings for drainage In underground PVC
I am not concerned about a small opening. However, we use a lot of conduit for street crossings where we have direct buried cable. This conduit will fill up with dirt, mud, silt, etc. over time and make it useless unless we plug the conduit with something. Here you are talking about an opening into the conduit run that is as large as the conduit itself.
I am not concerned about a small opening. However, we use a lot of conduit for street crossings where we have direct buried cable. This conduit will fill up with dirt, mud, silt, etc. over time and make it useless unless we plug the conduit with something. Here you are talking about an opening into the conduit run that is as large as the conduit itself.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
Re: T fittings for drainage In underground PVC
Fishing past the T would probably be a treat, moisture and mud or not.
Fishing past the T would probably be a treat, moisture and mud or not.
macmikeman
Senior Member
- Location
- Planet macmikeman
Re: T fittings for drainage In underground PVC
If you are in an area that gets subterarrian termites, this is a great way to help them get into the building, although I have witnessed where they ate thru the pvc wall of the conduit anyway and then tunneled up along the conductors and made a great mess inside a switchgear.
If you are in an area that gets subterarrian termites, this is a great way to help them get into the building, although I have witnessed where they ate thru the pvc wall of the conduit anyway and then tunneled up along the conductors and made a great mess inside a switchgear.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: T fittings for drainage In underground PVC
It would make a great home for a chipmunk or some other rodent. Beside the fact that some areas have a very high water table and in some parts of Florida you dig the require depth of 24" for under road ways you can hit water. There are many varmits that would love the new home though and the added teething material (conductors) will be a added bonus.
It would make a great home for a chipmunk or some other rodent.
Beside the fact that some areas have a very high water table and in some parts of Florida you dig the require depth of 24" for under road ways you can hit water. There are many varmits that would love the new home though and the added teething material (conductors) will be a added bonus. Re: T fittings for drainage In underground PVC
Charlie, as far as mud and silt, these "T's" are in a gravel pit and to my knowledge the dirt covering these pits never showed any depression (up to 10 years later) after the pits were covered, which leads me to believe the openings were still intact.
George, we had no problem fishing these conduits, which btw were for fire alarm and communication systems.
As far as the varmits, we did see some mole crickets with a little trac hoe removing some of the gravel once, but a little mole cricket bait in their lunch pails solved the problem. :roll:
Roger
Charlie, as far as mud and silt, these "T's" are in a gravel pit and to my knowledge the dirt covering these pits never showed any depression (up to 10 years later) after the pits were covered, which leads me to believe the openings were still intact.
George, we had no problem fishing these conduits, which btw were for fire alarm and communication systems.
As far as the varmits, we did see some mole crickets with a little trac hoe removing some of the gravel once, but a little mole cricket bait in their lunch pails solved the problem. :roll:
Roger
charlie
Senior Member
- Location
- Indianapolis
Re: T fittings for drainage In underground PVC
I wonder how you get around 110.12(A)?
I wonder how you get around 110.12(A)?
- Location
- Massachusetts
Re: T fittings for drainage In underground PVC
How is a 'T' any different than an open bottom hand hole as far as silt getting in?
I have never seen the 'T' thing done but a typical spec that I see is that underground conduits are arraigned to drain.
For us this would mean drain toward one of these open bottom hand holes for small raceways or toward a manhole for larger raceways.
How is a 'T' any different than an open bottom hand hole as far as silt getting in?
I have never seen the 'T' thing done but a typical spec that I see is that underground conduits are arraigned to drain.
For us this would mean drain toward one of these open bottom hand holes for small raceways or toward a manhole for larger raceways.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
Re: T fittings for drainage In underground PVC
So, as someone who's worked with it, does it keep the conduit dry, or does it have any effect?
That's because you're probably better at it than I am...
Corruption starts at the bottom, you know...
So, as someone who's worked with it, does it keep the conduit dry, or does it have any effect?
Re: T fittings for drainage In underground PVC
Charlie asked:
After all, 225.22 and 230.53 both say that raceways shall be arranged to drain (although neither say anything about direct burry conduit). But they don't say anything about how to arrange them to drain. I specified a 1/4" hole to be drilled in a fitting.
Steve
Charlie asked:
The problem is when the conduit runs into a basement and 90's down into the top of a panel. The wire may be rated for a wet location, but the inside of the panel probably is not
After all, 225.22 and 230.53 both say that raceways shall be arranged to drain (although neither say anything about direct burry conduit). But they don't say anything about how to arrange them to drain. I specified a 1/4" hole to be drilled in a fitting.
Steve
izak
Senior Member
- Location
- Springfield, MO
Re: T fittings for drainage In underground PVC
one of the jobs that our company is doing right now has a large underground storm shelter, and it was specd to install drain boxes at some point in the conduit run between where the conduit enters the building and the switchgear or whatever the piping is feeding.. seems like it will basically be a jbox with a plumbing fitting -at or near the bottom- so the plumbers can pipe out of it and remove all the water that comes in from outside...
right now the basement is always standing in water, as our conduits are acting as a french drain for the jobsite
one of the jobs that our company is doing right now has a large underground storm shelter, and it was specd to install drain boxes at some point in the conduit run between where the conduit enters the building and the switchgear or whatever the piping is feeding.. seems like it will basically be a jbox with a plumbing fitting -at or near the bottom- so the plumbers can pipe out of it and remove all the water that comes in from outside...
right now the basement is always standing in water, as our conduits are acting as a french drain for the jobsite
charlie
Senior Member
- Location
- Indianapolis
Re: T fittings for drainage In underground PVC
IMO, all conduit that is entering a building below grade should be sealed against moisture.
IMO, all conduit that is entering a building below grade should be sealed against moisture.
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