----- Original Message -----
From: "Phil Camera" <kb9cry@comcast.net>
To: "William Q Meeker" <wqmeeker@iastate.edu>; <towertalk@contesting.com>
Sent: Monday, March 14, 2005 5:08 AM
Subject: Re: [TowerTalk] grounding radials: solid or stranded?
> Solid is the way to go. As I understand it, stranded wire can oxidize and
therefore lose "contact" or have high resistance between each strand. Since
it's the surface area of wire that carries the electrons, if the strands
lose contact with each other, strike energy may be forced to flow down a
single or less than all the strands in the wire and therefore losing current
carrying capability. Solid does not have that problem. Both Polyphaser and
ICE, two expert companies, as well as NEC, all specify solid conductors for
grounding. Phil KB9CRY
>
> > It has been suggested that stranded copper wire would have little less
> > inductance and thus be more effective.
> > Is there a clear choice or is this the trade-off that one needs to
consider?
> >
>
Phil makes the useful point about interstrand corrosion.
However, I'm not sure that the NEC specifies solid conductors. It says
words like "a copper bonding conductor not less than AWG 6" without getting
into solid/stranded thing.
Also, the NEC doesn't cover much about lightning protection systems.
Download and read the (free) Mike Holt Low Voltage book. Lots of useful
information there on "non lightning" grounding for communications systems
(i.e. ham stations) as far as the code goes.
http://www.mikeholt.com/documents/lowvoltage/pdf/LowVoltBook.pdf
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