Installation instructions are considered to be a part of the UL Listing.

Status
Not open for further replies.

LJSMITH1

Senior Member
Location
Stratford, CT
OK if you look at the instructions for weather proof bell boxes. it says to use a sealing compound on the box closer plugs.This in it self would be a violation if the plugs are not sealed /. but how many of you will put a sealant around the threads of the box closure plugs? as not installed per Manufacture instructions.

I can tell you that I have personally seen FS boxes filled with water because the installer did not put any sealant on the filler plugs located on top of the box. The result was completely rusted receptacles or switches and attachment screws that could not be removed from the box. The only solution was to replace the entire box. I guess this is good news for the next electrician that gets to replace the box and guts...:roll::)
 

Riograndeelectric

Senior Member
I personally will put dab of Caulk on the threads of the fillers.
I am picky about not wanting water to seep in the box and corrode the devices. this drives me crazy when I run across a bell box that is full of water.
 

ohmhead

Senior Member
Location
ORLANDO FLA
So if a joint comes apart while being buried only 15 minutes after it was glued, whose fault is it? The manufacturer's?:roll: The good part is that when the conductors are attempting to be pulled, you will find the problem, dig it up, and fix it.:D

While 98% of the folks that glue PVC conduit this way won't have a problem, there are probably 2% who will. Same thing goes for plumbers who just have to pressurize the PVC supply system ASAP...:roll:


Well we do lots and lots of underground and i mean everyday duct banks on large projects its our fault if it comes apart .

But it never does but thats whats called out in instructions but in my line of work your not going to digg it up ever .

When its installed its 8 feet down and poured in concrete or 4 feet down and there 75 to 80 -4 inch conduits stacked on spacers try digging that up to fix it ! We run a mandrel down before we dont pull wire then find a problem .
 
Last edited:

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I don't seal bell-box ports unless the sealant comes with the box, but I do drill two 1/8" holes in whichever side of the box is the bottom when installed. Same with LB's and the like unless the conduit is rising to the fitting.
 

iwire

Moderator
Staff member
Location
Massachusetts
I don't seal bell-box ports unless the sealant comes with the box, but I do drill two 1/8" holes in whichever side of the box is the bottom when installed. Same with LB's and the like unless the conduit is rising to the fitting.

Same here, I assume water will get in and make sure it can get out.
 

LJSMITH1

Senior Member
Location
Stratford, CT
I don't seal bell-box ports unless the sealant comes with the box, but I do drill two 1/8" holes in whichever side of the box is the bottom when installed. Same with LB's and the like unless the conduit is rising to the fitting.

Many Red-Dot boxes are now coming with a small pouch of sealant in the bag for use with the port plugs shipped with the box.

As for drilling the 1/8" hole at the bottom of an FS or conduit body.....there wouldn't be a need to if the ports to the box were raintight and the gasket is installed properly.:)

I wonder if there is a manufacturer which suggests a "drilling for drainage" procedure in any of their literature? I know we don't, but does C-H, Appleton, T&B, or others?

I also had a related comment here:

http://forums.mikeholt.com/showthread.php?t=109376&page=6

Of course, the AHJ always has final call if they are OK with this.;)
 

LJSMITH1

Senior Member
Location
Stratford, CT
Well we do lots and lots of underground and i mean everyday duct banks on large projects its our fault if it comes apart .

But it never does but thats whats called out in instructions but in my line of work your not going to digg it up ever .

When its installed its 8 feet down and poured in concrete or 4 feet down and there 75 to 80 -4 inch conduits stacked on spacers try digging that up to fix it ! We run a mandrel down before we dont pull wire then find a problem .

I can tell you that you are very good at what you do!:) Even with soft joints, your conduit must be supported well enough to prevent any movement during the pour. I bet if you didn't glue them up, they would also stay together. Once the concrete cures, nothing is moving.

However, when you bury PVC immediately in dirt, the natural settling of the fill may put enough tension on the soft connection and pull it apart. Plus, any water in and around the trench may contaminate the solvent weld and allow water intrusion or allow the connection to separate. This is what I was referring to.

One of the things that affect cure time is the ambient temp. The warmer it is, the faster the bond will setup as the solvents evaporate faster. In colder temps, the weld may take up to 1-1/2 hour to reach maximum strength. I guess the instructions on the cans don't really take that into account...:)
 

LJSMITH1

Senior Member
Location
Stratford, CT
The NEC requires that raceways be arranged to drain.

Drain from "what"? :-?

Where in the NEC or WhiteBook does it instruct anyone to drill a drain port in these items? I believe the NEC is referring to factory installed drains and conduit pitch. Right?
 

ohmhead

Senior Member
Location
ORLANDO FLA
Many Red-Dot boxes are now coming with a small pouch of sealant in the bag for use with the port plugs shipped with the box.



Well thats because they need every bit of that. First any bell box is not what id call water resistance its some what kinda internal condensation from conduits that wet the insides in addition to the weather over the years .

Most come with your cheapest gasket that last one year if your lucky its not a good gasket to start with let me ask who do you work for and are you a electrician LJSmith just wondering.
If you look at most bell boxes the two screws and that cover is not weather resistance to rain as advertised .
So if one drills a hole it helps with the factory defect of manufacture.
And may last one more year or two before it falls apart .

We install rigid 90 elblows with weep ports in conduit runs down here in florida as spec on most of our projects to help with water build up inside underground duct banks to let the water out .

Heres what i suggest build a weather proof or rain tight box with more than two screws and put a gasket on it thats a real gasket and teflon coat your threaded slugs and ill buy it .
 
Last edited:

LJSMITH1

Senior Member
Location
Stratford, CT
Many Red-Dot boxes are now coming with a small pouch of sealant in the bag for use with the port plugs shipped with the box.



Well thats because they need every bit of that. First any bell box is not what id call water resistance its some what kinda internal condensation from conduits that wet the insides in addition to the weather over the years .

Most come with your cheapest gasket that last one year if your lucky its not a good gasket to start with let me ask who do you work for and are you a electrician LJSmith just wondering.
If you look at most bell boxes the two screws and that cover is not weather resistance to rain as advertised .
So if one drills a hole it helps with the factory defect of manufacture.
And may last one more year or two before it falls apart .

We install rigid 90 elblows with weep ports in conduit runs down here in florida as spec on most of our projects to help with water build up inside underground duct banks to let the water out .

Heres what i suggest build a weather proof or rain tight box with more than two screws and put a gasket on it thats a real gasket and teflon coat your threaded slugs and ill buy it .

Condensation and rainwater are two different things - only in quantity. :roll: While there is not much that can be done about limited condensation inside a closed raceway system, there is much that can be done to prevent rainwater from entering a raceway or enclosure. Significant amounts of condensation may take years to generate, but that is only due to continual air movement within the raceway. Without moisture-laden air moving into a conduit box or enclosure, there will not be any condensation occurring with temperature drops. However, significant amounts of rainwater can enter with only one rainstorm if a box or conduit body is not sealed properly.

If you are installing standard, epoxy-coated aluminum FS boxes or conduit bodies in a marine environment, you should probably go with PVC or Stainless Steel versions instead. Most aluminum conduit bodies or boxes will last a long time in most environments if the epoxy coating is not removed or if they are in constant contact with water.

The gasket supplied with the standard FS box is typically closed cell foam - not rubber. It works for most installs if carefully handled and applied. Are they a bit 'fragile'? Yes. Would it be better if the FS plugs came with sealant already applied. Sure.

Many manufacturer's are continually looking to cut the costs because the bean counters at the supply shops freak out when the costs don't go down every year...:roll: What the end installer gets the bare minimum in product that just meets the UL requirement (in a lab).:cool:
 

ohmhead

Senior Member
Location
ORLANDO FLA
Well the biggest problem in florida is the water table were below it in some areas water will enter pvc and rigid conduit is the worst .

We use drains and elevation changes to overcome some issues but its a bigg problem conduits must be sealed that enter a main switchboard from out doors to indoors with duct seal or fire seal water proof silcone pipe dope self leveling .
We can not have air flow thur conduits its a fire code thing they must be sealed and its also for rodents who could enter also .

So air flow is not going to happen .

We use alu conduit above grade and in by example a pepsi plant or a milk dairy plant Appleton sells the thread dope we use on fittings .


Appleton makes the joint compound for there threaded fittings .

Water can not be stopped ever it comes thur pvc conduits thats install correctly they fill up days after your done installing its just a problem we must deal with as electricians find ways to overcome this but we need the manufactures to listen or come out and look at what we need you can design products but until its out in the field for the real test will it really work .

Take care iam old and grumpy today:D !
 

ohmhead

Senior Member
Location
ORLANDO FLA
Maybe just grumpy! :grin:

Well were getting kinda old i like talking electrical and iam also willing to listen sometimes .

Weve been doing electrical since 1969 and iam still out in the field everyday with a crew we only do industrial & commercial work so i only get to work with conduit i know what it takes to manufacture a product and the ups and downs of it .
It must sell and even if its the best no one wants to pay the price so what do you do ?

Design it build it try and sell it but i think the most important product is one thats tested by the actual user of the product he will in fact tell you what you do not want to know but thats what you really need to have a better product then the other guy .
 

LJSMITH1

Senior Member
Location
Stratford, CT
Water can not be stopped ever it comes thur pvc conduits thats install correctly they fill up days after your done installing its just a problem we must deal with as electricians find ways to overcome this but we need the manufactures to listen or come out and look at what we need you can design products but until its out in the field for the real test will it really work.

No disrespect meant, but if PVC conduit joints are solvent welded and allowed to cure properly as instructed, there should be no water entering the conduit even if it is buried in the water table. There is really not much difference between the joint design as in a drain or supply plumbing application (the material is not for potable water, and fittings are designed for smooth conductor pulls). They should all be water-tight. Electrical grade PVC conduit is not porous and will not allow water to seep through - even if it is submerged indefinitely.

I have watched some electricians apply solvent to only part of the diameter of the conduit or fitting. When I questioned the thoroughness of the solvent application on both the fitting AND the conduit, they told me
that you only needed a little solvent to make up a good joint. Needless to say, I did not agree.:) I am sure others do this properly and I just got lucky to see the one guy that had a different method.;)

If the conduit is filling up (with sealed ends), then there is most likely a poorly welded coupling in the run buried in the water table.

...not looking to make you grumpier! ;)
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Larry,
In the real world properly installed rigid conduit, boxes and conduit bodies do fill up with water and in many cases the only practical way to prevent this is with a field installed drain hole, or as is often done in this area, a small notch in the conduit body gasket. Does the code or listing instructions actually permit this...probably not, but if you want an installation that works in the real world that is what you do.
 

iwire

Moderator
Staff member
Location
Massachusetts
If the conduit is filling up (with sealed ends), then there is most likely a poorly welded coupling in the run buried in the water table.

...not looking to make you grumpier! ;)

Almost all underground conduits in my area are flooded in the low spots.

The water can collect entirely from moisture in the air passing through the conduits. Now the NEC does require we seal the ends of conduits but to do so 100% air tight is all but imposable.

Good engineering specs will require they pitch toward hand holes or man holes with drains.
 

LJSMITH1

Senior Member
Location
Stratford, CT
Larry,
In the real world properly installed rigid conduit, boxes and conduit bodies do fill up with water and in many cases the only practical way to prevent this is with a field installed drain hole, or as is often done in this area, a small notch in the conduit body gasket. Does the code or listing instructions actually permit this...probably not, but if you want an installation that works in the real world that is what you do.


Unfortunately, rigid couplings (as made up standard without thread sealants or conductive pipe dope) are not technically watertight (as in a standard plumbing application - matching tapered fitting and pipe thread). The primary reason is that the straight thread couplings do not have matching tapered conduit threads. Standard, three piece unions also do very little in keeping rain out due to non-gasketed junctions. This probably constitutes a majority of the water intrusion locations within a run of rigid conduit. The standard straight coupling could be made with tapered threads, but it would certainly increase the cost - which many won't pay for. We already have a solution for a RT 3-pc coupling which we offer.

On the other hand, conduit bodies and entrance hubs have tapered threads, gaskets, and are listed as raintight. So are some compression fittings.

Perhaps one day, there will be a Raintight requirement for these types of standard threaded rigid fittings when used outside.:cool:
 

LJSMITH1

Senior Member
Location
Stratford, CT
Almost all underground conduits in my area are flooded in the low spots.

The water can collect entirely from moisture in the air passing through the conduits. Now the NEC does require we seal the ends of conduits but to do so 100% air tight is all but imposable.

Good engineering specs will require they pitch toward hand holes or man holes with drains.

I am sure that condensation moisture could significantly build up inside a long conduit run if allowed to pass a significant amount of moisture-laden air.

Pitching the conduit to allow it to drain into enclosures with installed drains is the solution, but the question was do you drill the enclosure and just leave the open hole without putting a one way drain device? Maybe one of those Gore-Tex patches (lets water pass one way but not in reverse) over the drain hole is the answer?
 

ohmhead

Senior Member
Location
ORLANDO FLA
Well typical project typical duct bank
image0-1.jpg



With all due respect your wrong pvc will leak it doesnt matter what method you use electrical conduit is not pressure rated like plumbing .

Its not made to seal sorry but i will be more than happy to have you come out and see for yourself .

We use your standard pvc glue and we pour it on 4 inch and 6 inch thats done because its not going in all the way unless you put lots of glue on .

Now the molded ends are not perfect from factory you may think they are tight but there not water tight now if a electrician was to use plumbers weld glue the gray stuff it would seal better but we use your standard electrical supply pvc glue and cleaner .

Its installed dry and we use a 5 lbs sledge hammer to pound them together each pipe is hit until it bottoms out you mark each pipe with a magic marker so we know its in all the way in coupling you cant pull it apart but it will leak .

Before we pull wire we blow out conduits with a 120 LB compressor clean it swab it run a mandrel down it and measure it after we pull wire when the head comes up its water city .

Pvc conduit leaks the main issue is its not molded perfect and they make pvc couplings short there not long enough and there not tight enough .

When we order conduit we ask for long bells this is a better seal but its still leaks i can not explain this any better .

We dont cut corners its done and we dont spare the glue .
Ductbanks.jpg
 
Last edited:
Status
Not open for further replies.
Top