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To: <>, <>
From: "Mark Robinson" <>
Date: Mon, 3 Jan 2011 14:18:09 -0500
List-post: <">>
So when you buy a generic surge protected power strip, do they have the 3 
way MOV protection installed in them?

Mark N1UK

----- Original Message ----- 
From: "Jim Brown" <>
To: <>
Sent: Monday, 03 January, 2011 1:50 PM

> Paul is exactly right.  I've spent the last 40 years in pro audio and
> large sound systems, where lots of expensive equipment is
> interconnected.  We learned about the issues that Paul is talking about
> the hard way, and came to the same conclusions that he is articulating.
> The SurgeX products are specifically marketed to the pro audio world,
> and are highly respected.  I began specifying them for all of the large
> systems I designed about 15 years ago. About the same time, I bought
> them to protect the expensive gear in my home and office.  About 7 years
> ago, SurgeX began hiring me to teach classes on Power and Grounding at
> industry conferences, and to write a tutorial on the subject.  I'm still
> teaching those classes, and recently updated the tutorial to cover power
> systems outside North America.  Less than 5% of the class content
> addresses  lightning protection or their products.
> It's also ABSOLUTELY CRITICAL that everything connected to the power
> system be properly bonded together per NEC. This includes EVERY ground
> rod, the CATV ground, the TELCO ground, all antenna grounds, the shack
> ground, conductive cold water, and any building structural steel.
> BTW -- the SurgeX and Brickwall products are based on the same rather
> interesting patent. Rather than being shorted out by an MOV, the surge
> is stored in a large inductor, then discharged slowly back into the line
> after the event.   Thus, the surge protector does not raise the
> potential of the equipment ground, where it cause failures of
> interconnected equipment.  An important limitation of this concept is
> that it is not practical to build inductors rated for circuits of more
> than about 30A.
> 73, Jim K9YC
> On 1/3/2011 7:59 AM, Paul Christensen wrote:
>> Surge diversion to the ground conductor can raise the ground potential
>> unequally between equipment.  If the rise and fall of the ground 
>> potential
>> is equal across interconnected equipment on a branch circuit, there's 
>> little
>> issue.  During a surge event, small amounts of resistance can create 
>> large
>> amounts of potential difference between grounded equipment.
>> By storing the surge energy and slowly dissipating it onto the neutral (a
>> conductor actually meant for carrying current), the surge event does not
>> create a potential difference between grounded equipment:
>> > From the descriptions in the above links, you can see why the ONLY 
>> > place for
>> "all three modes" of MOV protection is at the service entrance.
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