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

Wed Nov 12 10:54:49 EST 2014

Some additional thoughts -

Once you are considering 4" or larger conduit, check out SDR 35 pipe.  
HD doesn't have it, although I've seen it at Lowes.  Check with 
commercial suppliers, they usually stock lots of it.   It has a wall 
slightly less than schedule 40 at a lower price. It comes in "sanitary" 
and "drain" grades, the sanitary has rubber gaskets and costs more, the 
drain glues together with PVC cement.  While new my primary line (12kv?) 
to a new service transformer is in 2" sch 80, that was the directional 
drillers choice, only sch 40 is required by PSE.  So, it is hard for me 
to see why sch 80 is needed for any amateur radio conduit.  I installed 
400' of 4" and 6" SDR35 drain down 24" and medium size tractors and 
pickups run around on this field without problems.

For conduit loading I use "UGLYS" little yellow book, usually in the 
electrical section at HD.  While the rules are based on temperature rise 
in the conduit, they give a good idea of how many conductors will fit, 
including mixed gauges.  This book is invaluable to me for doing any 
serious electrical work.  I use liberal amounts TFE loaded cable pulling 
lubricant.  On the web I found the flat cable pulling polyester braid 
which has less tendency to cut into the conduit edge and won't introduce 
twist in the wires.  When buying my last 350' of 3" sch 40 conduit, I 
found exit collars that glue on to the od so there is no sharp edge.  
Large radius 90 deg sweeps (36" minimum) also help ease the pulling.  
Electrical code does require a bushing for larger than 1/2" adapter 
threads, it's just a good idea for coax etc.

Grant KZ1W

On 11/11/2014 10:53 PM, Roger (K8RI) on TT wrote:
> 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)
>>>
>>>
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>
>