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[Towertalk] Ground wire impedance

To: <>
Subject: [Towertalk] Ground wire impedance
From: (W1UK)
Date: Tue, 30 Jul 2002 20:19:21 -0400

I am curious as to why all the building lightning rod systems I have seen on
barns and homes use stranded wire in a rope lay,  from the rod to the ground

Harger Lightning Protection sells many sizes of multi strand bonding
conductors.  They identify them with their cross-sectional area measured in
cm.  I also have a few Andrews hardline grounding kits that use stranded

Perhaps manufacturers sacrifice some performance for flexibility?

----- Original Message -----
From: <>
To: <>; <>
Sent: Tuesday, July 30, 2002 8:32 AM
Subject: Re: [Towertalk] Ground wire impedance

> In a message dated 7/29/02 10:26:52 AM Pacific Daylight Time,
> writes:
> > There seems to be some debate over multiconductor wire for grounding.
As I
> > see
> >  it, the only advantage of stranded cable is mechanical flexibility.  I
> don't
> >  think "skin effect" (current flowing on the surface) has much to do
> >  stranded wire, since the strands are all touching and are all in each
> other's
> >  magnetic fields. What is good is to maximize the surface area of the
> > cable
> >  -- by making it into thin/wide strap (or hollow tube) instead of a
> >  circular cross-section, keeping the same amount of copper per foot.
> >  minimizes the inductance.  (Yes, that amounts to the skin effect
> -
> >  placing all the copper near the surface of the conductor.)
>     Two things. First, stranded wire is NOT acceptable for ground systems.
> Each strand will oxidize and then the strands will be electrically
> from each other. Use solid wire or copper strap only.
>     Next, while the multi-strands do offer more surface area over single
> strand, if you need more earth contact you should use copper strap instead
> the multi-strand stuff. Using copper strap in rocky or other poor earth
> conditions instead of wire is a good way to improve the effectiveness of a
> potentially poor ground system. Another poor earth technique is to lay
> rods horizontally if you can't get them in vertically.
> Cheers,
> Steve    K7LXC
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