[Elecraft] [OT} Whole House Surge Protection

[Jim Brown]

On 2/1/2013 10:21 AM, Mark Bayern wrote:
> Someone brought out the fact that a power strip or some other device with a surge protector built in should cover everything on that particular leg.  It's a parallel circuit.

Nope.  ANY shunt mode device (MOV) operates by conducting the spike to 
the green wire or the neutral.  The resulting current raises the voltage 
on the green wire (which is connected to the chassis of the equipment 
plugged into the "protected" outlet) to some very high value, depending 
on the spike that sets it off. In the case of lightning, this can be a lot.

Now, consider equipment connected to two different power strips, with or 
without an MOV, or to different locations, or to another ground.  ALL of 
those other points will be at a different potential as a result of 
seeing the same spike, and again, in the case of lightning, that can be 
a VERY large difference. it is the DIFFERENCE in potential from one 
piece of gear to the other that fries those Ethernet ports, and it would 
also fry signal interconnect circuitry for audio and video.

THIS is why MOVs are a really bad idea on branch circuits. Those of us 
working in pro audio have LOTS of interconnected equipment, often at 
widely separated points, so we learned all of this the hard way nearly 
20 years ago. Our solution has been to use SERIES-MODE Surge Protectors, 
and that has been quite effective.  SurgeX and Brick Wall are the only 
two companies I know of that have licensed the series mode patent. Their 
products are not cheap, but they work.  I have SurgeX protectors on all 
of my ham gear, computers, and audio/video gear.

73, Jim K9YC