codequestion
Banned
- Location
- MD, USA
Engineering plans call for underground receptacle without GFI protection. Anyone have any idea as to who sell them or where in NEC underground receptacle article/section would be?
Underground receptacle
- Thread starter codequestion
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ptonsparky
Tom
- Occupation
- EC - retired
I would be interested in know what is the intended use for these things.
A storm cellar or underground storage, thinking the salt mines of Kansas, is one thing but just a hole dug in the yard is something else.
A storm cellar or underground storage, thinking the salt mines of Kansas, is one thing but just a hole dug in the yard is something else.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
I don't know what you mean by "underground receptacle." :?
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
This is the only one that I am aware of: https://www.legrand.us/markets-solutions/outdoor/ground-box.aspx
AFAIK it is a fairly new product. Never seen one in the wild yet though.
ptonsparky
Tom
- Occupation
- EC - retired
Well isn't that just slicker than s___ on a doorknob!
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
I see a risk that a damaged power cord plugged in could provide an air exit path, allowing the water level to rise at least to the height of the cord sheath break.
I could be mistaken, but I believe I priced these and they were about $1000 each. Sounds like a lot, but when there aren't any other options.....
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
I have seen those on paper also. And they would be GFCI protected.
gadfly56
Senior Member
- Location
- New Jersey
- Occupation
- Professional Engineer, Fire & Life Safety
OK, so not for the holiday lighting display. :lol:
:lol: Which is exactly what happens to any underground J-box installation eventually, devices installed or not.
JAP>
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
I don't follow you, the "diving bell" design doesn't depend on any sort of sealing around the power cord.
Cheers, Wayne
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
The diving bell effect requires that the space inside the bell be airtight. A damaged cord could provide an air leak to the outside.
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Barbqranch
Senior Member
- Location
- Arcata, CA
- Occupation
- Plant maintenance electrician Semi-retired
A diving bell doesn't need to be water tight below the connections. Diving bells are by their very nature open at the bottom.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
Take a diving bell and run a hose from the inside to any point outside in open air and all the air will come out.
If the end of the hose is far enough down underwater then the air will not escape. (If the hose starts out full of water then as long as the top end is below the top surface of the bell you may also be OK?)
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wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
If I follow the idea correctly, then if the cord jacket is damaged both inside the diving bell space, and outside at a greater height, but is otherwise intact, it could provide an enclosed path for air to escape. In which case when flooded the water in the diving bell will rise up to the height of the interior damage.
Seems like this could be prevented in one of two ways: ensure the jacket inside the diving bell is undamaged, or put a hole in the jacket at its bottom-most point, so that the jacket floods there and doesn't allow air to pass. Maybe this second way is not advised (although my sump pump came with a plug with an air relief opening on it, so perhaps it is not so crazy).
Agreed?
Cheers, Wayne
Seems like this could be prevented in one of two ways: ensure the jacket inside the diving bell is undamaged, or put a hole in the jacket at its bottom-most point, so that the jacket floods there and doesn't allow air to pass. Maybe this second way is not advised (although my sump pump came with a plug with an air relief opening on it, so perhaps it is not so crazy).
Agreed?
Cheers, Wayne
Netpog
Member
- Location
- Boston, Massachusetts, USA
I see it for ~$200 online at a couple places.
Search for "Wiremold XB814".
Clever design. I like the fact that it locks.
codequestion
Banned
- Location
- MD, USA
But if you read the fine print:
They work with XB814 cover assemblies (sold separately).
https://www.middleatlantic.com/products/wiremold-products/outdoor-av-and-power/outdoor-ground-box.aspx
That makes them $1200 each
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