# Hand vaults subject to flooding, conduits filled with clay.



## five.five-six (Apr 9, 2013)

I have a new customer with about a 20 acre yard, all dirt. They were having trouble with their cameras and some electrical. I come to find out most of the underground is wired in CMR cat 5 and besides being a hot wet mess, fails cable sweeps and needs to be replaced. Unfortunately the conductors are stuck with silt worse than 20 year old yellow 77. I tried soakeing, blowing and finally spent the last week digging up conduits and replacing 10’ sections of conduit leading to the hand vaults. 

What came out of the hand vaults was solid clay silt. You could literally make pottery with it. 

Normally I would seal conduits in hand vaults at the end of the job with red concrete tape but in this case, there is so much dirt on this lot and it does get flooded that I want to seal the conduit better to avoid this happening again. 

Right now I am thinking of stuffing some paper or cloth or possibly chico a few in to prevent expanding foam from going down into the conduit. Is there a better way of preventing silt from accumulating in the conduit?


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## paulengr (Oct 8, 2017)

five.five-six said:


> I have a new customer with about a 20 acre yard, all dirt. They were having trouble with their cameras and some electrical. I come to find out most of the underground is wired in CMR cat 5 and besides being a hot wet mess, fails cable sweeps and needs to be replaced. Unfortunately the conductors are stuck with silt worse than 20 year old yellow 77. I tried soakeing, blowing and finally spent the last week digging up conduits and replacing 10’ sections of conduit leading to the hand vaults.
> 
> What came out of the hand vaults was solid clay silt. You could literally make pottery with it.
> 
> ...


Except for PVC and some somewhat exotic European stuff conduit is not sealed and you shouldn’t assume it ever is. It is pretty normal for conduit to be “cemented” in over time even in indoor industrial plants depending on what is around. This should be obvious because GRC for instance is identical to schedule 40 water pipe but plumbers put some kind of thread sealants in it while electricians just dry fit. There is not a sealant because nobody has a need to seal something that is not sealed in the first place. The purpose of conduit is to protect the wiring and in some cases provide bonding.

Two options to consider. You could use waterproof connectors like Myers hubs and waterproof compression fittings for EMT. That will stop splashing but can’t hold pressure if it is ponded over and won’t stop whatever gets into vaults backwashing. Similarly PVC conduit is schedule 4” water pipe in electrical grey instead of white. It is solvent welded so sealed for water and creates a water tight joint. Last and this is my best recommendation is ditch the conduit. Just use armored CAT 5E which is suitable for direct burial. You can hand dig it or use a plow to just pull it in, no trenching needed unless you live in very rocky soil.



https://www.usawire-cable.com/pdf/cat-5e-armored.pdf



Lots of manufacturers but it’s a low volume product so unless you are buying 20,000+ feet where you can direct order a whole run from a cable plant (at unbelievable prices) you are at the mercy of consolidator inventories like Omnicable. The armor is for varmint protection so they can’t chew through it. Inside is a regular CAT 5E. They just shoot it through an MC machine instead of a bunch of THHN.


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## paulengr (Oct 8, 2017)

Also the most common sealant is duct seal. It’s a clay impregnated with oil so supposedly it never quite fully hardens. Purpose is some weatherproofing (nut fully) and fire stop to preserve fire ratings.

Another one is more of a cement used to seal against explosions (hazardous locations) but you pretty much have to drill it out and replace everything if you ever have to remove it.

Red tape is for placing over duct banks in trenches so that diggers are supposed to know there are electrical lines (yellow for gas). In reality they just dig them all up anyway.


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## splatz (May 23, 2015)

I am a big believer in duct seal, I would use that rather than chico. Chico is just too hard to remove. You have to make sure the conductors are not touching each other or the conduit, they have to be kind of individually wrapped in duct seal. If you want to go an extra measure you could make a huge lump of spray foam around the entire duct seal glob and the end of the pipe. 

When I want to level up from duct seal I switch to mastic. They make it in a putty that you can apply the same way as the duct seal. The 3M mastic has been pretty impressive for me. 

I am assuming the conduit is EMT or RMC, if so I'd wrap the joints with pipe wrap, the black stuff, not that red concrete tape. The pipe wrap is made for the job. If you can afford it, the mastic tape would probably be even better. If it's PVC, properly applied PVC cement makes an actual welded joint, the tape would not really be necessary. The only thing I could think of to make it better would be bedding the conduit in sand to make it less prone to cracks and breaks. 

You could go the other way and just give up and direct bury and resign yourself to digging if you have to move or add but I'd at least try to make it work in conduit once myself. 

Did you put a 45 on the end of the pipes in the vaults to keep them off the bottom of the vaults? A few inches of elevation can make a huge difference in how much seepage runs into the conduit. 

I wonder how it would work out if you ran direct bury cable in a flexible drain tile.


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## 460 Delta (May 9, 2018)

What about the 2 part mold maker liquid silicone, stuff some cotton balls in the conduits and pour in the liquid silicone.


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## Southeast Power (Jan 18, 2009)

I would keep it simple and use duct seal


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## 99cents (Aug 20, 2012)

A Canadian would have thrown in Teck Cat 6 and power cable and then gone home and watched the Canadian women kick American ass playing hockey.


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## Wirenuting (Sep 12, 2010)

I've had the best luck with ridgid pipe, arranged to drain into the hand vaults. I'll place a good layer of gravel below the vault to give the water someplace to drain.. 
If I can't pitch the run into the vaults, Duct Seal, Perma-Gum works well. 

We have clay here that is like concrete. Even a sump pump will be covered with a thick, hard coat of that clay after 10 years. The clay gets suspended in the water and coats everything like calcium on a shower head. 

And I've never met an underground run that stayed dry. But I've seen older runs of ridged that were like new after 30+ years of being buried.. These were in trenches that were below the wet clay level and back filled with dry, compacted clay..


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## Slay301 (Apr 23, 2018)

Drill 1/4 holes in the 90s for draining


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## tmessner (Apr 1, 2013)

I have used a Polywater sealant product with good results: Polywater FST Foam Duct Sealant – Seals out water, gases, and rodents.


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## five.five-six (Apr 9, 2013)

splatz said:


> I am a big believer in duct seal, I would use that rather than chico. Chico is just too hard to remove. You have to make sure the conductors are not touching each other or the conduit, they have to be kind of individually wrapped in duct seal. If you want to go an extra measure you could make a huge lump of spray foam around the entire duct seal glob and the end of the pipe.
> 
> When I want to level up from duct seal I switch to mastic. They make it in a putty that you can apply the same way as the duct seal. The 3M mastic has been pretty impressive for me.
> 
> ...


Yes, I actually use 90’s into the vaults most times and bring them up as close to the top as I can and still form the cables inside. All I ever use underground is either PVC or ocal and I always expect either to be full of water within a year. And I seat my vaults in 1/2” gravel or similar. The water isn’t the issue, it’s all the silt at this location. This lot is at the base of a small mountain range and when it floods, it floods. I just want to reduce the amount of mud that gets in there. 


I ended up dragging a rag through most of the conduits and then blowing them out with a screw compressor. 

I just want to keep most of the mud out.


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## five.five-six (Apr 9, 2013)

These are runs that are all at lest 150’ many of them have structures or semi-permanent equipment over them. Redigging the entire run periodically is not an option


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## 460 Delta (May 9, 2018)

99cents said:


> A Canadian would have thrown in Teck Cat 6 and power cable and then gone home and watched the Canadian women kick American ass playing hockey.


Is that so?


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## canbug (Dec 31, 2015)

Clean out the pipe using a self feeding tip. We use it for dirt, clay and ice in our conduits with and without wires. Works great.








Tim


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## Jlarson (Jun 28, 2009)

We put the good ol B4T style PVC boxes in our vaults for controls and instrument runs so we don't have big dirty piles of splices.


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## five.five-six (Apr 9, 2013)

Do you need a different one for for each trade since of conduit?

It may be all for not, I’m finding most of the couplings aren’t even glued. The last one I repired today was 1-1/2” SCH40 and had no glue and wasn’t even in 1/2” 



canbug said:


> Clean out the pipe using a self feeding tip. We use it for dirt, clay and ice in our conduits with and without wires. Works great.
> View attachment 158135
> 
> Tim


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## paulengr (Oct 8, 2017)

five.five-six said:


> Do you need a different one for for each trade since of conduit?
> 
> It may be all for not, I’m finding most of the couplings aren’t even glued. The last one I repired today was 1-1/2” SCH40 and had no glue and wasn’t even in 1/2”


All electrical lines in a common raceway must be rated for the highest nominal voltage. Generally this isn’t a problem, with power wiring according to Code. Code is not concerned with electrical interference…that’s an engineering issue. It’s all about what happens during a fault. Code also isn’t concerned with the loads themselves as such. So even though Ethernet has 1500 V of isolation and is ungrounded (if it meets specs) it is still not allowed in general wiring because the conductors are too small to withstand a ground fault in the time it takes to trip. It’s irritating but it’s legally required.

The “but” here is when mixing AC systems be careful of long runs of heavy current loads running right next to controls. For example a common issue is when someone runs a couple hundred feet to a motor and then runs 3 control wires in the sand conduit for a start/stop button station. Often the induced current in the controls is enough that once you start the motor, you can’t stop it! This isn’t a problem with DC. Again Code is concerned with faults, not good practice and not with control or interference issues.

The second issue which applies to you is that CAT 5/6 is a type of power limited (communication) cable. Read the power limited rules carefully. You cannot mix general wiring and power limited wiring in the same raceway without separation with a divider or 2 inches of air gap. Within the power limited category there are 3 classes of circuits and there are rules about what can mix. In class 1 for instance you can have some AC 120 V loads too.

Fiber is something of an enigma in the Code. I mean it’s fiber, especially ADSS (all dielectric) so technically it’s an insulator but within a raceway you are supposed to use inner duct to separate it.

The final issue is interference with comms. With communications cables first look at your cables. Fully shielded cables that are grounded properly (one end only) such as coaxial cables or foil shielded Belden style cables are very noise immune and will mix well with almost anything. Twisted pair wiring is about 10 dB worse and generally pretty good but not as good as shielded. Finally straight wiring like standard alarm or telephone wiring is a noise attractor and big trouble. Second look at the signal type. DC controls are fairly immune to almost all interference. Low bandwidth “baseband” style communications such as analog phone lines (the worst), RS-232, and to some degree RS-485 are very noise sensitive. That’s one reason some long lines use digital 4-20 mA but it’s rare. With analog 0-10 V is in the same high susceptibility category. Digital high speed comms (Ethernet, ARCnet) and analog 4-20 mA are inherently fairly noise immune. The 4 mA and low impedance prevents analog signals from picking up trash near the noise floor unlike 0-10 V, and Ethernet actually has a notch filter at 60 Hz and the signal format is designed to avoid anything below 100-200 Hz anyway. Last look at the loads. Variable frequency drives, HAM radio transmitters, heavy switching contacts that switch often, and bug zappers are horrible noise generators. Run these separate from comms.

None of the concerns in the last paragraph had anything to do with Code. It’s more of a good practices thing. You shouldn’t generally have a problem with Ethernet UTP with a lighting circuit for instance but better use STP with a bug zapper or HAM radio, and analog phone should be separate or shielded. So if you want to mix, upgrade the cables.

Use common sense with non electrical. Sprinkler lines do leak once in a while. Gas lines shouldn’t be mixed with electrical for obvious reasons. It is convenient to have one vault but you are asking for trouble.

Finally if you are pulling new think about all the labor involved in redoing everything. Direct burial is just that. If it fails you have a 50/50 shot at removing most wire from most duct banks no matter how it was installed. If it doesn’t come out easy it eats up a lot of hours fighting it. And if it won’t come out it eats up hours and costs digging everything up compared to just running direct burial cable once.


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## canbug (Dec 31, 2015)

Most of our underground is 2 inch and usually 200 ft between pulpits. 

Tim


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## five.five-six (Apr 9, 2013)

paulengr said:


> All electrical lines in a common raceway must be rated for the highest nominal voltage. Generally this isn’t a problem, with power wiring according to Code. Code is not concerned with electrical interference…that’s an engineering issue. It’s all about what happens during a fault. Code also isn’t concerned with the loads themselves as such. So even though Ethernet has 1500 V of isolation and is ungrounded (if it meets specs) it is still not allowed in general wiring because the conductors are too small to withstand a ground fault in the time it takes to trip. It’s irritating but it’s legally required.
> 
> The “but” here is when mixing AC systems be careful of long runs of heavy current loads running right next to controls. For example a common issue is when someone runs a couple hundred feet to a motor and then runs 3 control wires in the sand conduit for a start/stop button station. Often the induced current in the controls is enough that once you start the motor, you can’t stop it! This isn’t a problem with DC. Again Code is concerned with faults, not good practice and not with control or interference issues.
> 
> ...


I almost never mix my electrical and limited power circuits in the same raceway, there are some exceptions but generally no

code does concern itself with interference, IG circuits for instance. 

I run DB rated cables inside existing conduit when possible. Every time you trench you face the possibility of hitting something. On this job i ran thousands of feet of cable and then it becomes a probability of getting something. Not to mention the labor involved in moving customer’s materials and equipment and the hazards associated with open trenches in a working yard.


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