Sealing underground conduit(pvc)

[linwue]

We have a service mounted on the outside of the bldg. and the inspector is requiring that we seal the conduit with duct seal,not sure if that's a code requirement.The other end of the pipe is located at the xfrmr. Need some help,please

 

[Jim W in Tampa]

We have a service mounted on the outside of the bldg. and the inspector is requiring that we seal the conduit with duct seal,not sure if that's a code requirement.The other end of the pipe is located at the xfrmr. Need some help,please

Not required by NEC

 

[Volta]

300.5(G) to seal against moisture.

 

[kwired]

There is this:

230.8 Raceway Seal.

Where a service raceway enters a building or structure from an underground distribution system, it shall be sealed in accordance with 300.5(G). Spare or unused raceways shall also be sealed. Sealants shall be identified for use with the cable insulation, shield, or other components.

But it does not apply if you do not enter a building.

 

[kwired]

300.5(G) to seal against moisture.

300.5(G)

(G) Raceway Seals. Conduits or raceways through which moisture may contact live parts shall be sealed or plugged at either or both ends

Not often an underground raceway will allow moisture to migrate through in a way that would enter and contact live parts.

 

[Volta]

300.5(G)



Not often an underground raceway will allow moisture to migrate through in a way that would enter and contact live parts.

Low humidity in the wet location conduit?

 

[Jim W in Tampa]

Never seen it done and i live where its always wet. All it will do is trap water

 

[macmikeman]

I live where there are hills. If a meter socket is lower in elevation than a handhole up by the street, and the utility conduit is not properly sealed at both ends, a fountain of water can come out the socket after a heavy rainstorm. I have seen exactly that on multiple occurances. One was a gusher.

 

[Volta]

I live where there are hills. If a meter socket is lower in elevation than a handhole up by the street, and the utility conduit is not properly sealed at both ends, a fountain of water can come out the socket after a heavy rainstorm. I have seen exactly that on multiple occurances. One was a gusher.

I think we'll need a little bit more than duct seal for that one! :grin:

 

[linwue]

When it says moisture does it mean condensation,otherwise I'm not sure how water would come in contact with the terminations

 

[Volta]

When it says moisture does it mean condensation,otherwise I'm not sure how water would come in contact with the terminations

Yeah, since they did not say water, we have to include any form of moisture, in my opinion.

 

[kwired]

Low humidity in the wet location conduit?

Wouldn't that actually draw moisture into the conduit instead of to the live parts?

 

[linwue]

Thanks for the input that should help

 

[linwue]

I live where there are hills. If a meter socket is lower in elevation than a handhole up by the street, and the utility conduit is not properly sealed at both ends, a fountain of water can come out the socket after a heavy rainstorm. I have seen exactly that on multiple occurances. One was a gusher.

I would consider that a faulty installation

 

[Volta]

Low humidity in the wet location conduit?

Wouldn't that actually draw moisture into the conduit instead of to the live parts?

Oh, I was just trying to put words in your mouth, sorry. I was wondering if you could state that an underground (wet location) conduit (with water in it, as always happens), would not contain enough humidity to allow moist air to reach the live parts.

300.5(G)

Not often an underground raceway will allow moisture to migrate through in a way that would enter and contact live parts.

And if not some random underground PVC with the ends stubbed up, when does 300.5(G) apply?

 

[kwired]

I live where there are hills. If a meter socket is lower in elevation than a handhole up by the street, and the utility conduit is not properly sealed at both ends, a fountain of water can come out the socket after a heavy rainstorm. I have seen exactly that on multiple occurances. One was a gusher.

230.53 Raceways to Drain.

Where exposed to the weather, raceways enclosing service-entrance conductors shall be suitable for use in wet locations and arranged to drain. Where embedded in masonry, raceways shall be arranged to drain.

It is hard to drain a raceway fast enough in your situation to keep the water out of the meter. Backflow devices will not work with the conductors in the way:grin:

 

[Jim W in Tampa]

Sending duct seal to BP maybe it will work

 

[Volta]

Sending duct seal to BP maybe it will work

:grin: :grin: :grin:

 

[macmikeman]

230.53 Raceways to Drain.

Where exposed to the weather, raceways enclosing service-entrance conductors shall be suitable for use in wet locations and arranged to drain. Where embedded in masonry, raceways shall be arranged to drain.

It is hard to drain a raceway fast enough in your situation to keep the water out of the meter. Backflow devices will not work with the conductors in the way:grin:

Believe me when I tell you it is not uncommon to have 12-15 inches of rain in a 24 hour period here. Usually happens 2 or 3 times a year. I never had a problem myself yet, but I did have one where I put a 24" x 48" concrete pull box in the yard right before a meter riser, just so we could get it to drain out before it could shoot out the conduit at the socket. That set me back an extra 500 bucks but I consider it good insurance. The poco guys use expanding foam - 2 cans worth at the head end trying to prevent this type of problem. Also paying attention to making sure the upper street side sidewalk pull box is elevated enough to prevent it acting like a storm drain helps, but sometimes cannot be avoided, since the city is in charge of the sidewalk elevations.