[TowerTalk] Water in Conduit... the fix

[Jim Thomson]

Date: Thu, 05 Mar 2015 08:22:58 -0600
From: Patrick Greenlee <patrick_g at windstream.net>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Water in Conduit...

Those of you unable to keep water out of your conduit have my sympathy.  
I know how irritating it could be. If your conduit is assembled properly 
and doesn't leak leaving the airborne moisture as your target then put 
desiccant bags in the conduit and plug the ends of the conduit where the 
cables enter/exit.  Various ways to plug include duct tape, spray foam, 
wadded up paper coated with silicon caulk or...

Patrick   NJ5G

####  .....or  use  DUCT SEAL.  Available at any home depot...in the electrical dept. 
Comes in 1lb packages.    It’s the Standard to use to seal conduit ends. At the telco 
I worked at, they had it in 10 lb bags.   Duct seal works  great..since its like kids plastercine. 
Pliable, and easily stuffed in there, and molded to fill all the air gaps.    Easily removed when
it comes time to add one more cable... or remove a cable. 

##  leaving conduit open is just asking for trbl.   Even if the conduit terminates  inside your
basement, or terminates inside a metal or plastic nema  box,  you still use duct seal. 

##  In nema boxes out doors, or stuff like remote ant switch boxes, etc,  put a lot of 
desicant inside..aka.. silica gel.   Silica gel absorbs up to 40% of its weight in water. 
Seal the boxes up air tight..then with silica gel inside, they will be bone dry.  Change 
the silica gel out once every year.   If a box has power to it, a pair of those metal
finned resistors and some voltage through em 24-7 also works very well.   Just a bit
of constant heat will ensure the box remains  dry..and the silica gel absorbs the rest.
2nd resistor is for redundancy.   

##  Im not a fan of metal nema boxes, since they are more prone to condensation forming
on the inside.  Some will use weep holes on the low point to let water out.  If u use a weep hole,
use the bare min.. like one...maybe two at most...and no bigger than  .15625 dia,   
( five sixteenths).   .125 inch or less is usually not big enough..and can become plugged with debris. 

##  If the weep hole is made too big, the silica gel inside will begin to try and absorb moisture
from the outside, high humidity ari..like rain and fog, high humidity condx, etc. 

##  Install large diam conduit ..like the 4 inch stuff....and forget putting holes on the bottom side of it,
Utilities don’t.   Make sure its all bone dry b4 gluing the sections together. 

Jim  VE7RF