[TowerTalk] [Bulk] Re: Schedule 40 or 80 PVC Conduit Underground

Wed Nov 12 11:43:23 EST 2014

Sand fill around the conduit is sometimes required by code, but it 
washes out if there is any grade and an opening.  Compacting fill is 
another choice - called "5/8 and down" here, "#2 road base" in CA, the 
gravel is < 5/8" with the fines from crushing and it compacts hard 
enough to be a road surface.  The goal is no rock larger than an inch or 
so in contact with the conduit, so graded dirt also works.

The codes here require vertical separation of low voltage and power 
lines, but most folks ignore that and the bury depth requirements for 
home-owner installed 12-2 or 14-2 UF (UF not Romex for underground!).  
Toss the UF in the trench before the conduit and it is less likely to be 
dug up accidentally.

I don't "get it" for having holes in my conduit!!  Yes, there will be 
condensation and underground rated cables will last the longest, but WHY 
let water in on purpose??

Direct bury coax with self sealing is flooded with silicone grease. 
Trying some surplus flooded RG8 once was one too many times for me, what 
a mess for connectors!  Silicone flooded is the gold standard for 
Ethernet, RG6 and POTS direct burial cables.

In conduit, I've standardized either on hardline or Buryflex and try to 
find polyethylene jacketed control cables since they last much longer 
than pvc jackets and are rated for direct burial.

Grant  KZ1W

On 11/12/2014 8:01 AM, Gary J - N5BAA wrote:
> In the area I live in electricians recommend back filling the trenches 
> with builders sand.  It's not hard to do here as there is no such 
> thing as a freeze level in our soil (water lines just covered with 3 
> inches of soil won't freeze) so the trenches aren't deep, but we have 
> lots of rocks and I don't like refilling the trench with rocks - makes 
> it too hard to dig a second time if needed - sand is easier.
>
> What is the feeling about adding extra unused coax runs in the conduit 
> for future whatevers??  Also, it has been recommended to me to use the 
> Direct Bury coax even though it is going inside a conduit.  It is self 
> sealing against any possible cracks, pin point holes etc.
>
> What do people think about running a length of direct bury 12 gauge 
> romex electrical line with a plug on the shack end and a socket on the 
> tower end inside the conduit.  That way one can energize the extension 
> cord when needed and have it de-energized at all other times.
>
> Could one run the long 50 ft sections of 4 inch black drain line with 
> a few holes drilled in the bottom to provide for drainage of 
> condensate??  Or the 10 foot white pipe with the holes drilled in one 
> side to ensure drainage.
>
> Gary J
> N5BAA
>
> -----Original Message----- From: Patrick Greenlee
> Sent: Wednesday, November 12, 2014 9:28 AM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Schedule 40 or 80 PVC Conduit Underground
>
>
> Very good advice, guys.  I'll add that if you are burying conduit
> underground consider going significantly larger than the minimum to pull
> your current needs through.  The cost difference is not a big deal so I
> standardized on 4 inch and find that eventually I need the extra 
> space.  If
> you bury deeply enough such that any traffic driving over the finished 
> job
> will not crush the thin wall S&D then that is easier to work with and 
> less
> expensive.  I'm currently (except for hiatus for weather) burying a 
> pair of
> 4 inch PVC S&D pipes in the same trench, a 280 ft run to service three
> towers with 140 ft spacing.
>
> A minor caveat RE not worrying about moisture or water in the 
> conduit.  If
> the coax or other wires or whatever are essentially moisture or water 
> proof
> then no worries but some "stuff" will let water get in over time. I use
> buried PVC conduit to protect from critters chewing up the unprotected 
> wires
> and it is very convenient to be able to add cables without having to 
> trench
> again.
>
> If you are concerned about water vs some particular lines you are running
> and they are small enough you can pull them through the low pressure drip
> irrigation roll tubing rated for 100 PSI that comes in 100 ft rolls for
> about $12 at the big box stores and then pull that through your conduit.
> Irrespective of naysayers comments to the contrary I have done that 
> easily
> single handed several times.
>
> Best of luck with your project.
>
> 73,
>
> Patrick    NJ5G
>
>
>
> -----Original Message----- From: Roger (K8RI) on TT
> Sent: Wednesday, November 12, 2014 12:53 AM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Schedule 40 or 80 PVC Conduit Underground
>
> On 11/11/2014 9:45 PM, Larry wrote:
>
> 2" will work fine with a snake and wire pulling soap.  Check on how the
> electricians do it.  I've seen them pull so many wires through conduit
> (steel and not EMT) that there was an electrician every 6 feet or so,
> pounding on the conduit with hammers (in time)  You couldn't pull them
> out. If you were lucky, you could pull out a few, one-at-a-time until
> they were no longer compressed, but we're talking real world, "I'm gonna
> reuse this--I hope"
>
> "For me", I'd  use conduit that would easily hold at least twice as many
> cables as I planned on using.  I'd need convincing to use something as
> small as 2".
>
> I make it a practice, not to have splices or connectors in the conduit.
> I usually have them within about a foot of each end.  I end the conduit
> in a junction box large enough for a grounding plate for all coax
> jackets, whether I plan on grounding in there or not.  I try to allow
> for the unseen future even if it does cost a little more.  A little more
> now, can save a LOT of work and money later on.  If the run is flat and
> no more than a 100-200 feet, I don't even glue the sections together. I
> make the run slightly long so the junctions are under pressure and wipe
> the inside coupling surfaces with a light coat of silicone grease. Never
> had a sealing problem and after years in the ground, they come right
> apart.  Easy to put in and easy to take out.
>
> Typically the conduit is to protect the cables and little else, but they
> sure can make additions a lot easier later on..  I used to install a "Y"
> at the low points with a cap on the unused side. I'd add a few small
> holes for drains.  I don't bother any more.
>
> Conduit can be schedule 40, 80, thin wall plastic sewer pipe, plastic
> water pipe. IOW, A slippery tube of sufficient size to handle the
> cables, plus possible future expansion.    Unless in a very dry
> environment, I'd avoid thin wall/EMT as it will rust and the price goes
> up rapidly with size. Any more, I don't worry about water in the
> conduit. If the coax is unbroken it shouldn't be a problem.
>
> Leave a messenger cable in the conduit plus a length a bit longer than
> the run coiled in a junction box at one end or the other.  It can easily
> be pulled back so you can pull in additional runs from either end.  Just
> make sure the ends are hooked to something solid to prevent pulling an
> end into the conduit, out of reach.  I use 1/4" braided nylon. Cheap and
> slippery, but don't pull it around sharp corners.  It will eventually
> cut into PVC conduit.
>
> 73 and good luck,
>
> Roger (K8RI)
>
>
>> I used 3 inch sch 40. I had a electrical pull snake for pulling coax 
>> and control lines down 150 feet of conduit without any trouble - not 
>> even pull soap was required.
>>
>> 73, Larry  W6NWS
>>
>> -----Original Message----- From: Drax Felton
>> Sent: Tuesday, November 11, 2014 9:29 PM
>> To: Allen Brier N5XZ
>> Cc: <towertalk at contesting.com>
>> Subject: Re: [TowerTalk] Schedule 40 or 80 PVC Conduit Underground
>>
>> I use 4" French drain line surrounded by gravel to let the moisture out.
>>
>>
>> I cannot imagine being able to slide coax 160 feet in 2 inch conduit. 
>> That would be tough.   I've built 5 towers all in excess of 180 feet 
>> from the house and always used 4" and it's hard enough.
>>
>>
>>
>>
>>
>>
>>
>> Sent from my iPhone
>>
>>> On Nov 11, 2014, at 7:16 PM, Allen Brier N5XZ <n5xz at earthlink.net> 
>>> wrote:
>>>
>>> I am running about 160 ft of 2" conduit underground for cabling. Is 
>>> Sch. 80
>>> required or will Sch. 40 do?
>>>
>>> Allen R. Brier N5XZ
>>> 1515 Windloch Lane
>>> Richmond, Texas 77406-2553
>>> (281) 342-1882 (Home)
>>> (713) 705-4801 (Cell)
>>>
>>>
>>> _______________________________________________
>>>
>>>
>>>
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