[TowerTalk] Fwd: WHOLE HOUSE SURGE SUPRESSORS

[David Robbins]

DANGER WILL ROBINSON!

those two examples are both BAD!

first the SurgeX one appears to show that when the MOV arresters divert current to the ground/neutral they feed that to one component, but not to the unshown other devices.  This one doesn't show the flow of current back out to the common ground point after it has been diverted onto the ground & neutral.  nor does it show the connection of all the other devices on the power system.... and it seems to label pin-1 as a 'back door' to damage the equipment.

In the Brick Wall page, they show again only a single device with stuff hanging off of it and are assuming that their device clamps the line voltage, stores the surge, and slowly diverts it to the neutral.  This may be good for surges caused by power line transients, but is hardly adequate to describe lightning transients that would easily flashover such a device.  the Brick wall device doesn't even show that it has to be connected to the safety ground also, nor cover what happens if the surge is on the safety ground (common in lightning events) rather than the incoming power line.

the most important function of a whole house or similar large arrester serving a building is to equalize the voltage between all the conductors so that all the equipment connected to it is as the same potential.  this prevents the equipment from becoming the path between the surge and where the surge isn't.  The importance of these is that they protect the equipment even if the surge is on the ground!  This is the common case when lightning misses the power line and hits the tower or hits the ground itself, the current through the ground system raises the ground voltage, the arrester at the service entrance/single point ground actually routes current FROM the ground TO the power conductors to raise their voltage so that any equipment on the other side all goes up at the same time.






Jan 3, 2011 11:05:23 AM, w9ac at arrl.net wrote:

Pete,

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:

http://www.surgex.com/library/22001.html

http://www.brickwall.com/how-it-works.html

>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.

Paul, W9AC





----- Original Message ----- 
From: "Pete Smith" 
To: 
Sent: Monday, January 03, 2011 10:13 AM
Subject: Re: [TowerTalk] Fwd: WHOLE HOUSE SURGE SUPRESSORS


> Why is this, Paul?
>
> 73, Pete N4ZR
>
> The World Contest Station Database, updated daily at 
> www.conteststations.com
> The Reverse Beacon Network at http://reversebeacon.net, blog at 
> reversebeacon.blogspot.com,
> spots at telnet.reversebeacon.net, port 7000
>
>
>
> On 1/3/2011 10:01 AM, Paul Christensen wrote:
>>> The gold standard is to have both... whole house to protect heavy
>>> equipment
>>> like AC compressors, etc. then end-point protectors for LCD TVs,
>>> refrigerator CPUs, PCs, Ham Radios, etc.
>> But only if the secondary suppressors are single mode (fault current path 
>> to
>> neutral), rather than devices that offer the popular "all three modes" of
>> protection. If secondary protection is desired after installing a
>> whole-house protector, it should only be single mode (e.g., SurgeX,
>> Brickwall, ZeroSurge). Except for the whole-house surge protector, 
>> "three
>> modes of protection" devices have no place in a home.
>>
>> Paul, W9AC
>>
>> _______________________________________________
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