quote:

Originally posted by cparktd:
Cable in conduit... if sealed at both ends should stop water or moist air intrusion will likely stop water collection in the conduit.

If you research it you will find buried conduit is listed by NEC as a "wet" location. There's a reason for that.

If you search on terms like "condensation buried PVC conduit" you'll find plenty of hits. The articles/threads will all say the same thing: Water in buried PVC conduit is a given.

The Belden engineer with whom I spoke recommended burying direct-burial UTP directly, as opposed to putting it in conduit, as it would normally be exposed to less water, for lesser amounts of time, directly buried than in conduit, where it would eventually be sitting in water all the time.

But if you believe you can beat the pros at what they know best: By all means: Have at it

quote:

Originally posted by ensigmatic:
Is that direct-bury fiber?

No, I still recommend putting it into either a flex conduit or PVC pipe. As it is fiber, you would be able to put it into the same trench as your electric items as fiber won't react to it.

You might call around to some small-business IT places in your area & see what they would charge to run fiber. With the trench open, it would be a couple hour job, might be pleasantly surprised if you find the right one.

Obvious advice: whatever you end up doing, make sure you have good comms before you put the dirt back in the trench!

quote:

Originally posted by ensigmatic:


But if you believe you can beat the pros at what they know best: By all means: Have at it

I hear ya on the possibility of introducing water in a poorly sealed conduit or from a physical break but it is certainly possible that it could be sealed well and in fact not all that hard.
Eliminating a physical intrusion is a wide variable that is not easily calculated.
Direct bury cable of course it recommended but still offers quite a bit less physical protection than a conduit.
As a "given" > NO but certainly something to factor.

Question: and something I don't know ~ will water penetrate the cable anyway?
Connection corruption would be obvious.
I always worried more about accidently cutting the cable or something moving and messing it up like an animal or insect, etc.

They do make directional wifi boosters. Look like tiny little satellite dishes. Sends the signal in a focused area. Might be a option?

Some of them are made to take a wifi signal a couple of miles.

quote:

Originally posted by smschulz:
I hear ya on the possibility of introducing water in a poorly sealed conduit or from a physical break but it is certainly possible that it could be sealed well and in fact not all that hard.

According to everything I've read on the subject: It's more likely than not. As in "near 100% probability." Several comments in a couple threads I found were "I've never seen buried conduit that didn't have water in it."

quote:

Originally posted by smschulz:
Question: and something I don't know ~ will water penetrate the cable anyway?

If it's direct-bury cable in moderate- to well-drained soil: Not appreciably. According to the engineer at Belden: Even direct-bury cable will suffer water intrusion if immersed in water long enough.

If he runs fiber, and the bottom of his trench is below his frost line, he may get away with it. As I noted, earlier: There's some disagreement as to the effect of water immersion on fiber.

I try not to design things based upon "May get away with it." Certainly not when fixing it, if I didn't get away with it, would involve something like digging up a trench like that.

Do it once. Do it right. Be done with it so you don't have to ever come back to it.

quote:

Originally posted by smschulz:
I always worried more about accidentally cutting the cable or something moving and messing it up like an animal or insect, etc.

Should not be a problem as far down has he's trenching.

quote:

Originally posted by myrottiety:
They do make directional wifi boosters. Look like tiny little satellite dishes. Sends the signal in a focused area. Might be a option?

Some of them are made to take a wifi signal a couple of miles.

Mentioned earlier. They're called point-to-point WiFi bridges.

The cable company, telco, and Att run their buried wires without conduit here, since they have to do it for a living I'd imagine they know what works best and what is easier to fix.

Based on experience here, when we had cable signal issues the cable company simply ran a new wire, didn't mess with pulling up the old one.

If it's going in the ground, then no conduit and direct bury cable, coax, fiber whatever you want to run. Other than that the wifi bridges would be the solution.

quote:

According to everything I've read on the subject: It's more likely than not.

As in "near 100% probability." Several comments in a couple threads I found were "I've never seen buried conduit that didn't have water in it."

OK, but just because a third party says they haven't seen where there was no water is hardly conclusive.
Not saying there is or is not valid but it is not something I would call ratified.
Too many variable's.
I would either want to experience it myself or have a more conclusive study/test.
Just the way I evaluate claims - .02

quote:

Originally posted by smschulz:
OK, but just because a third party says they haven't seen where there was no water is hardly conclusive.

Wasn't a third party, but several. Plus input from a Beldin engineer, plus NEC qualifying outdoor buried conduit as a "wet" environment.

quote:

Originally posted by smschulz:
Not saying there is or is not valid but it is not something I would call ratified.

Fair enough. For me the preponderance of the evidence I've seen has been enough for me to regard it as fact.

Do I believe it should be possible for buried conduit to stay dry(-ish)? Yes, I do. But years of experience have taught me many of my beliefs have been completely without merit

quote:

Do I believe it should be possible for buried conduit to stay dry(-ish)? Yes, I do.

You know what would be a great test is to take a conduit with a cable, fill it with water , seal it and measure the results.

quote:

Originally posted by smschulz:

quote:

Do I believe it should be possible for buried conduit to stay dry(-ish)? Yes, I do.

You know what would be a great test is to take a conduit with a cable, fill it with water , seal it and measure the results.

You mean non-direct-burial fiber? Yes: That would be an amusing test

Then freeze it

quote:

Then freeze it

Freezing wasn't on my mind here in Texas but sure too much water in a conduit and bursting in cold climates could be a concern. I can see that point.
But just the effect of water on a cable of any kind would be interesting.

quote:

Originally posted by smschulz:

quote:

Then freeze it

Freezing wasn't on my mind here in Texas but sure too much water in a conduit and bursting in cold climates could be a concern. I can see that point.

I thought about amending my comments, and I suppose I should have. I didn't mean conduit filled with enough water that freezing it would burst the conduit, but enough water in the bottom to cover the fiber, maybe half-full at the most?, then freeze it.

By all accounts that will permanently, physically damage the fiber.

quote:

Originally posted by smschulz:
But just the effect of water on a cable of any kind would be interesting.

FWIW: The Beldin engineer assured me that UTP sitting in water would eventually degrade in performance--even direct-bury cable.

The water penetrates the jacket and eventually penetrates the insulation. This changes the insulation's dialectic constant, thus upsetting cable impedance. Even before penetration of the inner insulation, what air gaps exist between the pairs will become water-filled, thus changing that dialectic constant. As you know: These cables are very carefully designed, engineered, and manufactured to yield the performance they do.

This message has been edited. Last edited by: ensigmatic,

OP here again.

Interesting (perhaps to some) related story...

Several years ago my Daughter rented the house next door and wanted to be on my network at her house. I had just wired an office building and had cat 5 left over.

I ran the regular indoor cat 5 scratched about two inches in the ground over to her house. Our frost line is 12 inches.
Distance between houses was about 40-50 feet. It worked perfectly until she moved, about two years. I simply ripped it up after she moved out.

Glad I know better now, and glad that I didn't know about all these options and complications back then!

quote:

Originally posted by cparktd:
It worked perfectly until she moved, about two years.

As far as you know

My bet is if you'd put a cable tester/qualifier on it, such as the Fluke I just bought a couple months back, it would not have passed.

When the cable becomes degraded it won't necessarily fail completely, it just won't perform to specs.

If your frost line is only twelve inches (ours is a good deal deeper than that) then you might get away with inside fiber in PVC conduit. (I'm assuming your trench is a good deal deeper than that.) Again: Not something I'd do, but I tend not to mess around when doing network stuff

 
For direct burial cable, would not putting a few inches of gravel at the bottom of the trench, then sand (or fine gravel) on top, help keep water away from the cable? Or is this assumed?

So, I’m genuinely confused as to how water would get inside a conduit.

It seems like either option means eventual failure of the cable - that just happens, IME - at least with the Cat 6 at work.

Replacing it, when it’s run through conduit seems vastly easier than having to bury a new line.

How much is the life span reduced by being in conduit?

quote:

Originally posted by Aglifter:
So, I’m genuinely confused as to how water would get inside a conduit.

It seems like either option means eventual failure of the cable - that just happens, IME - at least with the Cat 6 at work.

Replacing it, when it’s run through conduit seems vastly easier than having to bury a new line.

How much is the life span reduced by being in conduit?

It's not as big a deal as ensigmatic makes it out to be, IMO.
Electrical gets run in conduits all the time but no CAT 5e or 6 or Fiber???
PVC with solid length connections and silicone in the ends should do most very well for a very long time.
Even so it makes it much easier to run a new cable or additional cables if there is an issue, just fish them through.
I think the real issue is with faulty or incompetent installations or intrusions/damage to the conduit that could potentially cause issues.
Also the details of the requirements for the connection can vary widely and what course of action to take.
If it is a mission critical installation vs a casual installation it might make a difference on what steps you might take.
.02

quote:

Originally posted by henryaz:
For direct burial cable, would not putting a few inches of gravel at the bottom of the trench, then sand (or fine gravel) on top, help keep water away from the cable? Or is this assumed?

Not necessary in moderate- to well-drained soils.

The problem isn't water getting around the cable, it's the cable constantly sitting in water for long periods.

quote:

Originally posted by Aglifter:
So, I’m genuinely confused as to how water would get inside a conduit.

If the joints are not 100%: That's how water can get it. But that's not the problem. It's not really that hard to properly connect two pieces of PVC. The problem is condensation in the conduit. While it's possible to make it water-tight, it's not possible to make it air-tight.

quote:

Originally posted by Aglifter:
It seems like either option means eventual failure of the cable - that just happens, IME - at least with the Cat 6 at work.

Direct-bury cable is gel-filled. Between the outer jacket (and, often, an inner water barrier inside that) being water-resistant and the gel: Water doesn't have a chance to get to the individual pairs within unless the cable's immersed for a long period.

quote:

Originally posted by Aglifter:
How much is the life span reduced by being in conduit?

That depends

quote:

Originally posted by smschulz:
It's not as big a deal as ensigmatic makes it out to be, IMO.

Yeah... imma go with the Belden engineers on this one, if it's all the same to you

quote:

Originally posted by smschulz:
Electrical gets run in conduits all the time but no CAT 5e or 6 or Fiber???

125VAC or better at 60Hz vs. ±2.5V at several hundred MHz. A pair of wires that are Cat-nothing, where minor impedance changes between them are meaningless vs. four pair that are carefully designed to be Cat5, 6, or 7, where impedance changes over their length is detrimental.

As for fiber: As I noted, earlier: There's some disagreement as to the effect of immersing fiber in water.

I understand the attractions of conduit. I certainly never expected to find what I did when I researched it.