[TowerTalk] buried conduit

[John Sloop]

In the professional communications business, when moisture is an issue
in cables or conduits, we pressurize them.  In the building, we inject
compressed air that is passed through a dryer before entering the
conduit/cable. An alternative is to pressurize with nitrogen.  Many
times you will see a nitrogen cylinder strapped to a telephone pole with
a hose running to the cable to pressurize it when there has been a leak
in the cable -- a temporary fix until the cable is repaired. We install
pressure gages to monitor for leaks.

Usually, moisture in conduits is the result of humidity and
condensation. 

Hope this helps.

Regards, 
John AA0ES/AFA4JS