[TowerTalk] sealing conduit

[Jim Lux]

On 2/27/13 10:47 AM, Spencer wrote:
> There are hundreds of watertight connectors available that will not
> leak.

most people don't install hermetic feedthroughs at the end of the 
conduit, though.  And while the connector is water tight, that usually 
refers to ingress through the connector joining plane, not along the 
cable. So, unless you're mating that connector to a hermetic 
feedthrough, it might leak.

Flood the whole thing with dry gas if you worry about condensation.
> There are underground and submarine cables world wide that do not leak
> and have been in operation for decades.

Those cables are engineering marvels, and do in fact leak.  There's a 
big effort going on now to replace a ground wire that goes from the HVDC 
converter in Sylmar to Malibu, the last few miles of which runs in 
underground vaults and is oil insulated, and which leaks.  There are 
literally miles of HV power cables underground in the LA area, and 
there's always replacement efforts going on.

Undersea cables are generally better, but they're also a gazillion 
layers, etc. and hardly something a ham would be installing.