Ralph:
The conduit does pass through a
concrete wall, but it does not pass from under the building slab at any point.
Perhaps we could use a combination of seals, I am going to check the Sika
grouts, and see if we can weld a cap over it. We may be able to get a die
grinder into the conduit and remove more material, allowing better than an 1
1/2" of seal. If I can get some photo's I'll e-mail them.
Jim
In a message dated 4/29/2005 6:10:56 P.M. Eastern Standard Time,
[log in to unmask] writes:
Since you sent this to everybody, you can have my 2 cents'
worth, in addition to Ken's.
Got a problem coming up on
a project, we have an electrical panel in the
basement of a lab building
over at Rice University. We are going to abandon
the existing 50 year old
electrical feeder, and conduit to the panel, it was
run in rigid conduit,
using lead over rubber covered conductors, there is no
way we will be
able to remove the existing feeders. We are installing a new
conduit and
feeders to the panel. The problem is this, the existing conduit
has a
large amount of water in it (assumed to be ground water), this is
what
has precipitated the need to replace the panel, the water seepage
has
corroded the copper bussing in the panel. We intend on cutting the
conduit
off as close as possible to the wall, leaving a stub of conduit.
We will
then beat the old conductors into the conduit as far as possible,
lets
assume a maximum of 1 1/2". The issue I need help on is how best
to
permanently seal the conduit so that it does not leak anymore.
Assume this conduit passes through a concrete wall of some sort
where it enters your switchroom or whatever. We
probably
will not be able to weld a steel cap to the old galvanized
conduit. Epoxy
has been suggested, but I want to know if we encapsulate
the end, can we
assume that this will be permanent. My concern
would be that even if you seal up the conduit with epoxy, the conduit itself
will continue to take on moisture and will continue to rust, and that to the
extent the conduit passes through the foundation wall and into your
switchroom , the rust will put pressure on and crack the concrete, and your
foundation will get AFU and continue to leak where this conduit
is buried in it. Seems to me that you need to open the wall, cut
the conduit somewhere outboard of the outside face of the wall, and
then patch the wall with some sort of non-shrink grout. It would be
nice if you could get to the outer face of the wall and waterproof the area
through which the conduit passed, after you patch the wall, assuming that
the outer face of the foundation was waterproofed when it was
built. The total conduit run is about 100', it is buried
probably 3'-4' below ground, it is a 2 1/2" conduit, filled probably 50%
with conductors, I don't think there will be any hydraulic
pressure on
what ever seal we go with. Seems to me that you're gonna continue to
get water attempting to enter the building through the conduit
unless you kill the conduit beyond the wall line, in which case the water in
the conduit just pisses into the soil. Just want some professional
input. Let's see what everybody else says. The other question
is who tells you how to solve this problem, and whether you want to be the
father of this potential bastard child...which is to say, who (for legal
purposes) is the designer of the repair, and who gets sued if it
doesn't work right, or continues to leak into the
building?
Jim
Ralph