"Duane Bozarth" wrote in message
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[...]
Despite your best attempts, eventually there virtually surely will be
a leak and water will find a way in. Only underground-rated cable
should be used in an underground run despite the conduit. Normally
(unless there is an access tunnel in an industrial site, for example)
conduit is used to protect the cable from the above ground junction to
the required depth then the cable is laid in a trench. A protective
barrier is sometimes used over the cable, but not normally full run
buried in conduit. It's not an immediate danger, but eventually it is
virtually certain to get water...

I see. So conduit was never meant to be a substitute for rubber-sheathed
underground-rated cable in the first place. And here people were conveying
to me that rubber-sheathed underground-cable was something new in that it
didn't require conduit underground! So I chose conduit thinking that was
the 'tried-and-proven' standard method of laying underground cable. I now
see I got it wrong. Well, the cable hasn't been tied in to the power yet
(decided to wait until I can get the cash to hire a licensed electrician for
the inside-of-house wiring --mainly for insurance reasons). Guess I'll be
pulling out all the romex (as well as the single-strand-wires) from the
conduit and replacing with underground-rated cable then. I have junction
boxes underground too where power gets split to serve two separate
destinations. (The rubber-sealed junction box covers, I had reinforced with
silicone sealant --but come to think of it, silicone does in time lose some
of its effectiveness), Guess I'll have to modify the cable layout scheme,
in order to serve all of the separate power destinations, without those
junctions...


Danger, fogey story...

Used to work w/ online coal analyzers at mines, prep plants, etc. Had
location at mine in KY where they pulled the high voltage signal power
cable (2.4kV) and had to go from the control shack where the
electronics/computer were housed across a truck crossing to the analyzer
mounted on the beltline. That installation was the mine's
responsibility, wasn't around when they did it. Installed the unit,
brought it up, calibrated it, watched for a few hours, went home...two
weeks later, get call...it's not operating. Drive up, discover HV cable
shorted. Hood up the spare (we did require a spare be pulled in the
specs), it worked, calibrated, watched, went home. Within six months
second failed...turned out they had buried the cables in conduit and it
filled w/ water. HV instrumentation cable isn't designed for water
immersion and water also got inside the insulation. Didn't help they
had pulled the cable through the conduit by hooking it to a front end
loader when they couldn't pull it by hand , but that was secondary...

They pulled with wire through with a front loader?! LOL! Now that's a case
of applying too much 'brawn', as it were, and not enough brain. Why didn't
they just use an approved lubricant and avoid stretching (if not the risk of
breaking) the cable? (Don't try to answer. I'm sure you wondered the same
thing.)


Thanks,

Guest987