Hi Charlie,
On Sat, Jun 27, 2015 at 4:06 PM, Charles Cu nningham <
charlie-cunningham@nc.rr.com> wrote:
> Well, a few things to keep in mind, Mike:
> · Each time an MOV breaks down, Its breakdown voltage decreases a
> little, taking its break down voltage closer to the peak voltage of the
> line cycles.
>
Understood.
That Sycom meter base surge suppressor has been replaced three times at my
request. The last time, I made sure that it was a brand-new unit for the
very reason that you state. Still, it didn't work like I thought it should.
Regarding ground rods – if the ground rods take lightning strikes, the soil
> around the ground rod can “glassify” become glass from the heat of the
> lightning surges. As the soil glassifies, the rod is then surrounded by an
> INSULATOR – making it rather ineffective. It can be a pain, but it’s worth
> checking ground rods from time-to-time for degradation.
>
WOW! That's something that never occurred to me.
Here's a class-act company that specializes in very low resistance
grounding systems for as-good-as-it-gets lightning protection.
http://www.lyncole.com
A local friend of mine (W0PM, Rayfield Communications) has successfully
Lyncole's products on several tall commercial towers. They use a special
ground rod along with a thick layer of a powdered(?) chemical mix that
surround it. John is quite knowledgeable about this. If eHam were up, I'd
send you a link to something he said there.
In keeping with Tom’s remarks, the meter-base suppressors ARE common-mode
> suppressors that sit directly across the 240 volt line phases with a direct
> common-mode ground return.
>
I cannot think of a way of (or reason for) wiring a 240 volt 3- wire surge
suppressor so that there is only common mode protection but no differential
mode protection. How could that be the case? If there are two 130 VAC MOVs
from each leg to ground, wouldn't both of them conduct if a HV spike was
present across both legs?
73, Mike
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