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Subject:RE: Concrete as an insulator??? -- and now FCC/FAA
Author: Mike Hopkins mhopk...@keytek.com
Date: 08/24/99 5:25 PM
If I'm not mistaken, there IS an FAA
Concrete is a lousy insulator. It is frequently used as a poor conductor
in grounding systems. I think the conductivity of concrete was first
described by Uffer (spelling ???) after his work on protective grounding of
munitions bunkers. I can't find my copy of his paper right now so I can't
AM
To: gmcintu...@packetengines.com; ed.pr...@cubic.com; emc-p...@ieee.org
Subject: Re: Concrete as an insulator???
In a message dated 8/23/1999 5:05:26 PM Central Daylight Time,
gmcintu...@packetengines.com writes:
Does anybody know why the FCC - not the FAA has regulations
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From: Don Diego [mailto:zorro_1...@yahoo.com]
Sent: Monday, August 23, 1999 5:34 PM
To: Egon H. Varju; EMC-PSTC
Subject: RE: Concrete as an insulator???
Doug,
It sounds to me like this may be a good time to supply more information
to the group. High power, 200 kW, at what frequency? Are we
Doug,
It sounds to me like this may be a good time to supply more information
to the group. High power, 200 kW, at what frequency? Are we talking
13.56 MHz, 27.12 MHz, 40.68 MHz or are we discussing 18 GHz?
Just thought that this may change the discussion a tad.
--- Egon H. Varju
Hello all,
I would like to thank you all for your inputs on this thread. It turned out
to be much more interesting than I thought it could ever be. An I 've
learned quite abit more about concrete (from and electrical standpoint) than
I ever thought possible.
Once again, an example of the
I was just reminded that placing a battery on concrete will drain it, so
there must be conduction somewhere. Its amazing what one can learn from this
forum. Concrete was way down my list of things to look up.
As long as we have wandered down an unusual path I have one other question
that came up.
At 01:58 PM 23/08/1999 , Ali Elmi wrote:
Egon,
For evidence that concrete is in fact porous, all you have to do is look at
the black streaks near the top of Hoover Dam, which are the result of water
seeping through the dam over the years
I don't understand. If it is indeed leaking, why
Just to add a bit of trivia to this discussion, concrete increases
substantially in conductivity in the presence of ionizing radiation (x-rays,
gamma rays). This is well known and documented in the nuclear hardening
community. This is an indication of an inherent population of free charge
To: EMC-PSTC
Subject: RE: Concrete as an insulator???
Scott,
At 05:34 AM 23/08/1999 , you wrote:
I would beg to differ on your comment that Once the concrete is set,
there
is very little, if any, water absorption. I have water wicking through
the
concrete floor in my basement quite
At 03:39 PM 8/20/99 -0600, POWELL, DOUG wrote:
Hello all,
I have a very innovative engineer who has come up with a design idea that
uses concrete as an insulating compound in a very large inductor for a 200
kW switching power supply. Yup, this is the stuff you buy down at the local
building
Properly poured and cured concrete can still pass water. This is why the
Uniform Building Code requires pressure-treated wood for wood in contact with
basement floors, unless a separate barrier (i.e., in addition to the
concrete) has been installed.
Mike Sherman
FSI International
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Scott,
At 05:34 AM 23/08/1999 , you wrote:
I would beg to differ on your comment that Once the concrete is set, there
is very little, if any, water absorption. I have water wicking through the
concrete floor in my basement quite regularly. Having seen the salts that
are washed out of the
:43 AM
To: emc-p...@ieee.org
Subject:Re: Concrete as an insulator???
Doug,
Concrete is a fairly good conductor-- much more conductive
than most soils.
Electric utilities, radio stations, and amateur-radio
Doug,
Concrete may be made to work as an insulator, but conditions will have to be
carefully controlled. Most concrete tends to be somewhat hygroscopic,
although this varies with mix variables including type of aggregate used. I
have heard that large concrete pads are successfully being used as
Doug,
Years ago, I worked in a facility where I was told General Electric made
inductors for powerline carrier systems that withstood 700kV from high
power transmission lines. These were made from some sort of ceramic
compound, formulated for insulating properties as well as structural
And it is still a good insulator during a rain storm?? Or would the
torturous path of the water molecules embedded in concrete be too much to
create a free flowing conductive path? Wouldn't it depend upon the type of
concrete and/or the process??? ...
Before we get too carried away,
[SMTP:m...@california.com]
Sent: Friday, August 20, 1999 7:40 AM
To: POWELL, DOUG; EMC-PSTC (E-mail)
Subject: Re: Concrete as an insulator???
Not sure, but check into Light Rail. They use 600Vac (I believe) and use
the natural insulating qualities of concrete (where the rails are placed) to
give
Hi Doug:
Some years ago I did some tests on my concrete garage
floor using aluminum foil laid down on the floor.
I applied 120 volts through an ammeter to the foil,
and then measured the current from the 120 volts to
the foil. I wanted to learn how much current would
be conducted by the
Not sure, but check into Light Rail. They use 600Vac (I believe) and use
the natural insulating qualities of concrete (where the rails are placed) to
give fairly good isolation from ground.
From memory - the rails are the return terminal.
- Robert -
-
Hello
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