"Phil Scott" wrote in message
. ..

"guest987" wrote in message
news:uWuyd.546239$Pl.492525@pd7tw1no...
"Duane Bozarth" wrote in message
...
[...]
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!

Close but no cigar just yet. You do need underground
rated cable for UG locations...but you do not have to use
conduit beyond a certain depth...usually 32"..

You can go shallower if you have a concrete pour over it, or
if it is in conduit of various sorts...the *minimum depths are
all called out in the NEC... but that doesnt mean a persons
particular job is safe or right, depends on how soft the
ground is in worst case conditions (muddy etc, with heavy
vehicles over the top).. salt water infiltration as we have at
low levels near the coast in many regions.

and of course no J Boxes underground at all (unless they are
in a manhole etc)....

Then there is fudging... say for instance you had an oversized
plastic J box underground with very carefully bolted
connections, then those painted with insulating sealant, say 3
or 4 coats, then that wrapped in rubber tape about 1/8"
thick... then the J box filled with urethane roof sealant
(dries like tire rubber), then the water tight lid applied...
cement bulkheads poured at each side of the box so it couldnt
move or break at the conduit connections... well some guys
might call that safe enough for govt work. But it wouldn't
be legal. A short though would go directly to ground in
virtually all cases...so there are much worse actual hazards
in the world... a red head could move in next door for
instance.

If it were in well drained ground, not prone to getting muddy
it might be a lot closer to OK.. If it were in muddy ground
with loads driving over it... it would not be ones slickest
move.

You have to scratch your ass and figure these things out....
sometimes I burp too. that helps.

The NEC code is part of the fire code... over heated wire,
shorts where they can cause a fire or go to ground though a
person are the primary issues... When you are underground
the fire hazard all but dissapears, same with the shock
hazard...unless someone digs into it etc.

In your case, and wire being relatively cheap, Id install
separate runs on your job... if the ground is muddy or
freezes, Id go deeper than the NEC requires, Id use schedule
80 pvc conduit regardless. put a few long radius glued bends
in it so it can expand and contract without stress, be sure
its in sand on the bottom and a few inches of sand on top,
40 years down the road the next owner is going to love you for
it. To make it easier on yourself, go one size larger on the
conduit than required as well....so the wire will pull easier.
Or you can bury the cable direct with no conduit below 32
inches... some people then lay redwood boards over the top and
yellow plastic marking tape so that if anyone digs there later
they will hit the boards and the tape as a warning. That
saves you the work of putting in the conduit and a long wire
pull. If the wire goes under a drive way or road you may
want to slide a schedule 80 pvc section of pipe over that part
of the run... bury it a little deeper there as well...and
maybe even pour some concrete over the top, 3" or so with a
little rebar in it. All that exceeds the NEC...but remember
the NEC and all of these codes are *minumum requirements and
are sure not best practice in all cases.


As I get older, I find that doing a job to world class
standards or better gives me a warm fuzzy feeling inside.
..its satisfying... Im also finding that it doesnt take much
more effort in most cases.






Phil Scott


How about this scenario, (its an actual situation that I have). Water well
driller and home builder needed electricity supply. The anticipated use
time exceeded six months prior to the home being finished. The home
building did not start until October, the well was drilled in March. So, I
had to have permanent meter loop installed vice a temporary. This provides
power to the water well pump (30 amp breaker two phase), and a 120V GCFI
outlet (20 amp one phase) for the home contractor subs.

The house is nearing completion, and the house contractor is strongly
suggesting I have the meter moved to the house, and I have the lines run
from the transformer pole to the house. The house has an external main
panel connection to receive power from the meter. This would leave a pole
with a main panel sitting on my property with nothing for it to do.

What I would like to do is tie in to the main bus bar on the main panel
(240V 200 amp) on the current power pole, run the cable (wire size?)
underground to the main panel on the house. The house has a current max use
of 135 amps if all is going at once with all installed appliances, electric
water heater, electric heat/AC. Yes, its quite a small sq. footage home.
The house is approximately 50 feet away from the current power pole.

And, a detached garage was built. Its wired and ready to go. Its wired
strictly for one phase power. But, will run both phases to it for future
possibilities. It has a on/off input switch externally mounted which feeds
a small panel. This panel has three 20 amp circuit breaker feeding internal
lights, external lights, internal 115 outlets, and two external 115 outlets.
The garage is about 200 feet from the current power pole, and about 100 feet
from the house. This, of course, needs to be underground cable fed (wire
size?).