Pvc glue

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LJSMITH1

Senior Member
Location
Stratford, CT
This issue of keeping underground conduits dry comes up on occasion. I'll concur with the others who have said this is a pointless exercise. The NEC knows and understands that these are wet locations and requires them to be wired as such. That being the case, if they are required to be treated as wet locations anyway, why go to the trouble to keep them dry? It doesn't make sense to me. :confused:

Then why have dry conduit requirements above grade? It seems like a circular discussion to me. This would mean all conductors pulled above and below grade outdoors should be rated for wet locations.:confused: What would be the purpose of RT fittings? :confused:
 

iwire

Moderator
Staff member
Location
Massachusetts
This would mean all conductors pulled above and below grade outdoors should be rated for wet locations.:confused:

Check out 300.9, it is new for the 2008 but IMO always applied.

Check this out and notice the name. :)


3-63 Log #2234 NEC-P03 Final Action: Reject
(300.9 (New) )

Submitter:
Donald A. Ganiere, Ottawa, IL

Recommendation: Add new text to read as follows:
300.9 Raceways in Wet Locations. Cables and conductors installed in
underground raceways or raceways that are located in wet locations shall be
listed for use in wet locations.

Substantiation: The interior of raceways installed in wet locations is a wet
location and the cables and conductors installed in such raceways should
be listed for that purpose. I have submitted a proposal to delete the similar
requirement for underground installations that is in 300.5(B). This new
requirement will cover all raceways installed in wet locations.

Panel Meeting Action: Reject

Panel Statement: The requirement for cables to be suitable for the location
in which they are to be installed is presently addressed in Section 310.8, and
Table 310.13 applicable locations. Article 310 covers the general requirements
for conductors such as insulation types, designations, and uses. To add the
proposed text to Article 300 would be inappropriate since 300 deals with
wiring methods in general. Repeating this requirement in Article 300 does not
add clarity to The Code. See panel action and statement for Proposal 3-43.

Number Eligible to Vote: 13

Ballot Results: Affirmative: 13


3-52 Log #2257 NEC-P03 Final Action: Accept in Principle
(300.9 (New) )

Submitter:
Donald A. Ganiere, Ottawa, IL

Comment on Proposal No: 3-63

Recommendation:
This proposal should be accepted.

Substantiation: I understand that panel’s point that conductors must be
selected so that they are suitable for the locations where they are being
installed. The point of this proposal is to make it clear that the interior of any
raceway installed in a wet location is a wet location. That is not a completely
accepted idea in the field. A section was added, 300.5(B) in a previous code
to make it clear that the interior of all underground raceways is a wet location.
This is the same issue with raceways that are installed in wet locations. The
interior of the raceway will be a wet location and conductors or cables installed
in these raceways must be listed as suitable for use in wet locations. If the
interior of raceways in outside or wet locations is not also a wet location, why
do sections 225.22 and 230.53 require that “raceways on exteriors of buildings
or other structures shall be arranged to drain”? Note: This proposal covers
underground raceways and raceways in wet locations and if accepted, you
should also accept Proposal 3-43.


Panel Meeting Action: Accept in Principle
Revise recommended text for 300.9 to read:
300.9 Raceways in Wet Locations Above Grade. Where raceways are installed
in wet locations above grade, the interior of these raceways shall be considered
to be a wet location. Insulated conductors and cables installed in raceways in
wet locations above grade shall comply with 310.8(C).


Panel Statement: The panel accepts the recommendation to create a new
300.9 for aboveground wet locations and has chosen to place the underground
installation requirements in 300.5(B). The text was not deleted in 300.5(B)
since this entire Section 300.5 applies to underground installations. Providing
additional underground requirements in a new 300.9 could be missed by the
user of the Code. The requirement for using wet location listed conductors
in the proposal was changed to “complying with 310.8(C)” because there are
three different methods to comply with insulated conductors and cables used in
wet locations. They must be:
(1) Moisture-impervious metal-sheathed;
(2) Types MTW, RHW, RHW-2, TW, THW, THW-2, THHW, THHW-2,
THWN, THWN-2, XHHW, XHHW-2, ZW; or
(3) Of a type listed for use in wet locations.
See the panel action and statement on Comment 3-20a (Log #CC300).

Number Eligible to Vote: 13

Ballot Results: Affirmative: 13

Comment on Affirmative:

CASPARRO, P.: See my explanation of vote on Comment 3-20a.
 
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don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Then why have dry conduit requirements above grade? It seems like a circular discussion to me. This would mean all conductors pulled above and below grade outdoors should be rated for wet locations.:confused: What would be the purpose of RT fittings? :confused:
I don't see any real reason for the RT EMT fittings...except maybe the listing agency needed so more income for another round of testing:D
 

LJSMITH1

Senior Member
Location
Stratford, CT
I don't see any real reason for the RT EMT fittings...except maybe the listing agency needed so more income for another round of testing:D

:)

Don, I wish it was that easy to explain. The RT requirement has been in place for EMT compression fittings for quite awhile. However, the only RT requirement for a Rigid or IMC threaded connection is for a Hub. How or why these specifications were created involved a lot of folks and from all walks of the industry.

Here is the RT specification and test method from UL514B:

8.6 Wet locations test
8.6.1 Two samples of each trade size of a FITTING intended for use in a wet location shall be tested as described in Clauses 8.6.3 and 8.6.4. As a result of the test, no amount of water greater than 0.1 ml or 0.1 g shall enter the FITTING. See Clause 7.1.5 and Table 19. In the United States, six samples of each trade size of a compression type FITTING intended for use with EMT and marked for use in wet locations shall be tested as described in Clause 8.6.3 and 8.6.4. See Clauses 7.1.5, 7.3.2, and Table 19.

In Canada, this requirement does not apply.

8.6.2 Prior to assembly, dry absorbent paper shall be placed in a resealable container. The paper and the sealed container shall be weighed. The paper shall then be removed from the container and placed in the interior of the enclosure at the point where the FITTING interfaces with the electrical enclosure and also where it interfaces with the cable, conduit, or tubing. A threaded end cap shall be used in place of the enclosure for a FITTING that is intended for securement to a threaded HUB only and marked in accordance with Clause 7.11.1.

8.6.3 The FITTING shall be assembled and vented to atmosphere to equalize the pressure during the test. The assembly shall be mounted under the apparatus described in Clause 8.6.4 and illustrated in Figure 4. The water spray shall be applied for 1 hour.

8.6.4 The water spray apparatus shall consist of three spray heads constructed in accordance with the details illustrated in Figure 5 and mounted in a water supply pipe rack as illustrated in Figure 4. The water
pressure shall be maintained at each spray head at 34.47 kPa (5 psi). The distance between the center nozzle and the product shall be 1.52 m (5 ft). The product shall be brought into the focal area of the three spray heads in such a position and under such conditions that water enters when the FITTING is in its normal mounting position.

8.6.5 Immediately following the water spray, the outside of the test assembly shall be wiped dry. The test assembly shall then be disassembled. The absorbent paper shall be removed and placed in the container. The container shall then be resealed and weighed. The difference between the weight of the paper before and after the test shall be used to determine the quantity of water.
 

btharmy

Senior Member
Location
Indiana
If the gorilla glue expands, is there a risk of any excess glue inside the conduit joint expanding and causing interference with fishing or pulling wire in the conduit? Just wondering.:roll:
 

ohmhead

Senior Member
Location
ORLANDO FLA
That Gorilla PVC glue isn't made by the Gorilla Glue company. Some offshoot or someone stealing their name.

http://www.gorillaglue.com/ToughTea...forumid/7/postid/320/scope/posts/Default.aspx

Does it look like normal Gorilla glue? How's the price on it? Normal Gorilla glue is awesome for gap filling.

Well sorry but its made by Gorilla glue http://www.gorillapvc.com/

And its only $ 65 dollars a gallon its very expensive, as far as it expanding it doesnt expand in air it expands under pressure if clamped or compressed.

Also if you put regular electrical pvc glue on a pvc conduit it comes out the coupling so whats the difference glue is going to be hanging and dripping out inside that pipe anyway its a spiders web inside a conduit thats why we run a sock thur it .
 
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LJSMITH1

Senior Member
Location
Stratford, CT
Gorilla PVC:
Gorilla PVC Cement LLC
P. O. Box 848969, Hollywood, FL 33084
(888) 367-4583

Gorilla Glue:
The Gorilla Glue Company
4550 Red Bank Expressway
Cincinnati, OH 45227
(513) 271-3300

I talked to Gorilla Glue Co. Apparently, at one time in the past, the two companies were the same. However, at this time, they are separate entities. According to the rep., there was an agreement to share the logo/brand image when they separated about 9 years ago.

So there you have it. You both are right (at one time or another). :D

Also, I asked her about the "expansion" of the PVC glue while it hardens. She said that the POLYURETHANE glue does that, not the PVC version. The PVC version is a solvent, water based cement that functions similar to standard PVC cements.:)
 

ohmhead

Senior Member
Location
ORLANDO FLA
This issue of keeping underground conduits dry comes up on occasion. I'll concur with the others who have said this is a pointless exercise. The NEC knows and understands that these are wet locations and requires them to be wired as such. That being the case, if they are required to be treated as wet locations anyway, why go to the trouble to keep them dry? It doesn't make sense to me. :confused:

Well its not a code thing its a kinda trade issue some jobs have lots of conduits and its just nice to have a conduit with out water in it let me give you a example lets say you have a duct bank new just installed and say you have 55 x 4 inch conduits there 450 feet long and you have lets say 50 gallons of water in each try getting a measuring tape or string thur it.

You kinda need to get that water out wouldt it be nice not to spend the labor taking water out all day?

I think most electricians dont spend as much time as some on different parts of our trade so sometimes we have different reasons on what we bring up on a post .

Meaning what type of work one does each day .

I hope this has help you understand better but i thought maybe there were others who might have the same issues.

I like to see what electricians think or do in other states a question that some may not clearly see but hopefully can understand its interesting to read the posts you can then see what others do .

I should not say this but there is more to electrical then the NEC its a trade by example the NEC is a rule book which we follow .
Take care
 
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rclacey

Member
This issue of keeping underground conduits dry comes up on occasion. I'll concur with the others who have said this is a pointless exercise. The NEC knows and understands that these are wet locations and requires them to be wired as such. That being the case, if they are required to be treated as wet locations anyway, why go to the trouble to keep them dry? It doesn't make sense to me. :confused:


Have you ever seen a foundation penetrated below grade with electrical conduits? How about conduit headed down hill to the foundation and penetrating below grade? I know I have, and there was a river running out
of the LB cover in the electric room, after a heavy rain. I don't think that was a river of condensation. Seems to me that if that pipe had been primed, it would have been pretty darn dry.
 

mivey

Senior Member
Have you ever seen a foundation penetrated below grade with electrical conduits? How about conduit headed down hill to the foundation and penetrating below grade? I know I have, and there was a river running out
of the LB cover in the electric room, after a heavy rain. I don't think that was a river of condensation. Seems to me that if that pipe had been primed, it would have been pretty darn dry.
Here?
River
 

ohmhead

Senior Member
Location
ORLANDO FLA
Have you ever seen a foundation penetrated below grade with electrical conduits? How about conduit headed down hill to the foundation and penetrating below grade? I know I have, and there was a river running out
of the LB cover in the electric room, after a heavy rain. I don't think that was a river of condensation. Seems to me that if that pipe had been primed, it would have been pretty darn dry.

Well rclacey you are correct in that statement i think one of our biggest problems in our state is all the high ground was built on many years ago .
Theres nothing left but SWOMP !

Now all the construction generally is on low lying swamp or filled in low areas which are meaning wet lands the contractors just build any place thats now and in the future its getting worse each year or iam just getting old .

We can not aways go level when we change elevations as the slab has different elevations from point a to point b we get a water pocket in the lower levels which needs to be blown out to get a string or tape in .

Good point i didnt say it before but condensation does not give you 50 gallons of water in 2 days and thats what we deal with in sunny florida on each project you can blow it out and in two days its back.

And the deeper you go it gets even more water in new work .

We have trenched long duct banks and have seen a spring running thur and have to stop and reroute .

Plus the contractors or construction managers put the berden on us in contract so we are responsible for our own dewatering system during construction nice guys this cost us hundreds of thousands of dollars on some projects which is very hard to estimate with out a site vist or soil samples of the area which is becoming the future estimators problem now .


Take care keep dry :D
 
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LJSMITH1

Senior Member
Location
Stratford, CT
Ohm,

If groundwater is a major concern in your area, as well as water finding its way into your conduit runs and/or enclosures, why not eliminate the source of the water instead of spending $$$$ and time on drainage systems and designs? From what you are saying, it seems like the bell-end coupling system is the main culprit as opposed to straight condensation.

What about cutting off all bell-end couplings and supplying a standard molded coupling? The molded coupling will have much more consistent tolerancing and certainly would fit tighter on the conduit. This, combined with proper PVC gluing technique would seem to eliminate any possibility of groundwater from entering the conduit run. I would also think that the added cost of purchasing a separate coupling, plus the labor of cutting off the existing bell coupling, would be much less than creating a drainage system.

It certainly would be worth an experiment, no?:)

Just my worthless $.02...:D
 

LJSMITH1

Senior Member
Location
Stratford, CT
Coincidentally, here is a very interesting article from EC&M:

Change Proposals
Pending Code Change Item for 2011 NEC
As noted in the NEC Committee Report on Proposals, 2010 Annual Revision Cycle, Code-Making Panel 4 has voted to accept a Code change submitted by Joel A. Rencsok of Scottsdale, Ariz. (Log #307 NEC-P04). The recommendation calls for adding a new section to Art. 225, which states:
"Raceway Seal. Where a feeder 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."

As noted in the substantiation summary, feeders entering buildings or other structures are no different than services. The requirements should be the same as noted in 230.8.

It sure would be easier to seal a conductor-filled raceway from significant air movement (and resulting condensation) than it would be to seal against a solid head of water pressure coming from groundwater sources. :confused:
 

ohmhead

Senior Member
Location
ORLANDO FLA
Coincidentally, here is a very interesting article from EC&M:



It sure would be easier to seal a conductor-filled raceway from significant air movement (and resulting condensation) than it would be to seal against a solid head of water pressure coming from groundwater sources. :confused:

Well we do seal our conduits from outside to inside with duct seal and also i do not know the brand name but its a gray spray foam for electrical conduits we dont have a water issue in gear just in the conduit .

Just the water during wire measuring and pulling time is the problem not after we dont care after wires in its not a problem .

As far as cutting the bells thats labor expensive and were not going to do that no one would waste conduit like that ever for a water issue its just not the way to go .
We have been using 20 foot pvc conduit lately its a lot better .

I know you may think a coupling is a good connection but there design short in length not a solid seal if you ask me and not a good underground practice they come apart with expansion and contraction of pvc conduits as conduits they move naturally i would not use in a duct bank .

Also a pvc coupling is the last thing we want on large sweep duct banks they can split or come apart .

When we stub up from a 90 deg elbow thur the slab up from the 90 we have found that a coupling if hit by a concrete pump hose or a skete machine it will break away and you now have concrete in pipe .

I would like to see pvc conduit made with a better coupling or the bell end that can twist together without glue a internal seal like not a threaded fitting but a screw type of connection .


Ive hit pvc conduit together and we have seen it push itself back out of couplings !

But will live with the water its just part of our everyday florida .

Dewatering has to be done to work in a trench safely thats not for the conduit problem that standard work practce.
 
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LJSMITH1

Senior Member
Location
Stratford, CT
Ohm,

Wow..It really seems like the joints are weak and barely bonded together - especially if they come apart so easily. I also don't see how a standard PVC coupling is any weaker than a bell-end PVC connection when properly glued and fully engaged with the conduit. As far as hitting PVC with something like a concrete pump - well I would expect it to break. SCH40 or SCH80 PVC is not indestructible, nor is it incredibly impact resistant.

As far as expansion of PVC, well, code requires expansion couplings at specified lengths.

Have you tried InnerDuct products? They really have some great products that might be better than the brands you have been using. http://www.innerduct.com/

Thanks for your input. Its been very enlightening.:)
 

ohmhead

Senior Member
Location
ORLANDO FLA
Well on most projects we use expansion fittings but only on elevated decks on expansion joints only we do not use them underground as pvc can move but only 1/4 of a inch and a bell coupling is around 5 inches in length the manufactures who make pvc say this is normal and not needed underground they make it to expand aready a standard bell is made to move pvc is designed to move a little .

You have a good point but you would need hundreds of exp fittings as direction changes underground would be a bigg issue and elevation changes on long runs and depth of conduits if in a concrete duct bank you might create a bigger problem from top to bottom as some duct banks are 10 foot high the concrete kinda holds it in place .

When pvc is used underground this is small amount of movement because the temp underground is not a condition to worry about it kinda stays the same year round anything below 4 foot in our area of work stays at a level and change is not a problem .

But a expansion fittng used on a underground in a duct bank of large conduits would put us out of bussiness its not going to happen . Bottom line we need a better seal to help us out but its the manufacturer who can help us only on couplings .
 
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