Hi Joe,
Yes, the AC power line is a common entry point. I agree that a good
whole house protector at the main feed is a good thing. I've bought one,
but haven't installed it yet. It is critical that the leads between the
protector, the power line, and the green wire be VERY short. It is also
critical that everything in your premises be bonded properly.
Earth connections are not SOURCES of trouble (unless they are not
properly bonded together), so they do not require protection. The lines
that need protection are all signal and control lines that enter your
premises, like CATV, telephone, and antennas. Again, it is critical that
protectors be properly bonded to the ground system.
You should absolutely avoid shunt mode (MOV) surge protection on branch
circuits (the sort of things built into outlet strips, and most
dedicated surge protectors). MOVs on branch circuits are more likely to
CAUSE damage than to prevent it. MOVs are entirely appropriate at the
service entrance if they are properly bonded. The ONLY safe protection
for branch circuits are SERIES MODE protection devices. I use and
recommend SurgeX products. Yes, I have done consulting for them --
teaching, technical writing, and some of their more difficult tech
support troubleshooting -- but I was specifying them for ten years
before they hired me for anything. :)
73, Jim Brown K9YC
On 9/13/2011 2:38 PM, Joseph or Ruth Patrick wrote:
Good Afternoon Jim
Excellent description of the NEC. Recently I had a near lightning
strike. My tower and ground system is set up per the nec as a single
point ground system. The strike took out 1 radio, 1 printer, a
Signalink USB interface, and a ceiling fan speed control in another
room. After much discussion with people much more knowledgeable than
myself it was determined that the spike entered thru the main AC feed.
I have decided to install a surge suppressor at the main feed. My
question is what about the ground line where it enters the shack.
Does this need protection or disconnection also? I am not an EE or an
electrician. I do have knowledge of the the NEC as it is adopted in my
municipality. I would appreciate your thoughts on this if you have
some time. Thank you in advance.
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