Gary:
There are a couple of reasons to install the PVC sweep inside the
concrete tower base:
1. Minimize total number of sweeps needed. In the case of my tower, I
installed a 3 inch PVC (way too small, BTW) as you suggested - outside the
concrete. To get from the top of the sweep to a steel box mounted on the
tower near ground level, I then had to install two 90-degree elbows (not
enough room for sweeps.) If I had installed the sweep in the concrete I
could have brought it up right into the bottom of the steel box, eliminating
the two elbows. However, I would have had to have the sweep PRECISELY
located BEFORE I mounted the box so the PVC would actually hit the bottom of
the box.
2. The sweep inside the concrete is protected from damage from things like
heavy construction equipment (in the case of the substation) or lawn
tractors, etc. (in the case of residential towers.) I frequently run into
my conduit with the lawn mower. I'm always careful, but it's still a risk.
I can't answer why Craig might want/need his conduit inside the base.
73 de
Gene Smar AD3F
----- Original Message -----
From: "Gary Schafer" <garyschafer@comcast.net>
To: "Gene Smar" <ersmar@comcast.net>
Cc: <towertalk@contesting.com>; "Craig Sande" <ae7i@yahoo.com>
Sent: Wednesday, March 30, 2005 1:56 PM
Subject: Re: [TowerTalk] Wet setting conduit?
> What advantage is there to having it come up in the tower base? I would
> put it along side and not in the concrete.
>
> 73
> Gary K4FMX
>
>
> Gene Smar wrote:
> > Craig:
> >
> > I've seen this done on many of my projects when I designed
electrical
> > power distribution substations for a power company. Typically this
> > technique is used when one crew installs facilities like underground
> > cable-in-conduit systems encased in concrete within the substation
proper,
> > and another crew continues the conduit system underground to the next
> > station. This is exactly what your contractor is proposing.
> >
> > I would caution, however, against installing too many of these
embedded
> > conduit sweeps in the tower base. Without doing the math, it would seem
to
> > me that too many (number is open to discussion/debate/calculation) such
> > columns of air within the concerete mass might jeopardize the mechanical
> > strength of the base itself. Caveat Amateur!
> >
> > 73 de
> > Gene Smar AD3F
> >
> > ----- Original Message -----
> > From: "Craig Sande" <ae7i@yahoo.com>
> > To: <towertalk@contesting.com>
> > Sent: Wednesday, March 30, 2005 1:29 PM
> > Subject: [TowerTalk] Wet setting conduit?
> >
> >
> >
> >>I am planning a tower base pour and my contractor has already dug the
> >
> > hole, framed it, and inserted the base. When it comes to placement of
the
> > conduit, he has suggested "wet setting" the conduit sweeps. The way he
> > described it to me is that rather than creating a trench to the base
ahead
> > of time and bracing the conduit, he plans on partially filling the hole
with
> > concrete, then submerging the conduit sweep to the wall of the hole with
> > some form of foam protective cap. Then after the concrete has fully
set, he
> > will trench down along the side of the concrete base, ream out the
> > protective foam cap, and extend the conduit to the house, ground
trenches,
> > etc.
> >
> >>Has anyone ever heard of this technique? I've tried to find information
> >
> > on the internet without much success.
> >
> >>Thanks,
> >>
> >>Craig, AE7I
> >>_______________________________________________
> >>
> >>See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> >
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any
> > questions and ask for Sherman, W2FLA.
> >
> >>_______________________________________________
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> >>TowerTalk@contesting.com
> >>http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
>
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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