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Re: [TowerTalk] whole house surge protectors

To: "'Mike'" <>, "'Tower Talk List'" <>
Subject: Re: [TowerTalk] whole house surge protectors
From: "Wes Attaway \(N5WA\)" <>
Date: Tue, 15 Apr 2008 20:52:03 -0500
List-post: <">>
I have had excellent results with the following items made by Cutler-Hammer:

SurgeTrap CHSPMAX (AC power lines)
SurgeTrap DHW4PT (handles up to 4 Telco lines)
SurgeTrap DCXCAB2 (handles up to 2 cable/sat coax lines)

They should be available at electrical supply firms who carry Cutler-Hammer
products.  I don't think they are a retail product. I purchased these about
4 years ago so the model numbers may have changed.

As has been pointed out by others on this list, the way to deploy these
things is in conjunction with other good single-point grounding practices
and other protection at the equipment.  These particular units are mounted
just below my power entrance panels and everything (power, telco, cable, ham
radio, etc) is connected together inside and to ground just on the outside
of the wall.

Since building this house 4 years ago we have had multiple "close" strikes
that have done considerable damage in neighbors' houses but the only thing
we have noticed is one GFI socket that "went bad".  It may have been bad to
start with but the lightning seemed to put it over the edge.

I have two wire antennas up about 65' in the pine trees and as far as I know
they have not taken a direct hit.  However, trees within 50' have been hit
so I know the strikes were close.  I have lightning arrestors on the ground
below the antennas and then the single-point grounding when the coax gets
inside.  So far, no equipment of any kind (except that GFI plug) has shown
any effects from the lightning.

We do have a 10KW generator (natural gas) that kicks in if power goes out.
All equipment in my office/ham shack operates via UPS units.  This includes
my Orion and several computers.  Since I do computer forensic work I don't
want to be in the middle of some two or three-day long process and have a
"blip" in the power feed shut down anything. It is nice to be able to sit
here and watch the lights go out and the Orion and the computers never
notice a thing. 

------------------ Wes Attaway (N5WA) ------------------
1138 Waters Edge Circle - Shreveport, LA 71106
    318-797-4972 (office) - 318-393-3289 (cell)
        Computer Consulting and Forensics
-------------- EnCase Certified Examiner ---------------
-----Original Message-----
[] On Behalf Of Mike
Sent: Tuesday, April 15, 2008 8:25 PM
To: 'Tower Talk List'
Subject: Re: [TowerTalk] whole house surge protectors

I see there is a "whole House" Surge protector at Harbor Freight LOT NO.
96822 on sale for 99 bucks, says it is good up to 70kA with lifetime
warranty up to $25,000.

Mike, K6BR

-----Original Message-----
 Subject: Re: [TowerTalk] whole house surge protectors

Jim and fellow Tower Talk members:

That message is kind of weird because I don't even use
the address to send e-mails and haven't
in many months since I switched from dialup to DSL.  

I wonder why if you got it through the list and I
didn't where the problem could be?  I use McAfee
internet suite protection and it checks all my files
every night about 3 a.m. CDT, plus its set to auto
update my AV files too.  

The mysteries of the internet never cease.

73 de Tom, WW5L

--- Jim Lux <> wrote:

> Tom Anderson wrote:
> > Jim and fellow tower talk members:
> > 
> > I'm in the process of having a 220 line run into
> the shack for a new 
> > Alpha 9500 amp my XYL and I picked up at the plant
> in Boulder a month 
> > ago.  Still waiting on the electrician showing up
> though.
> > 
> > While I had him on the phone I asked him (and yes
> I've known him for 
> > years (I was his son's Eagle Scout advisor) and
> he's done work for me 
> > before and does a lot of commercial work near us)
> about a whole house 
> > protector and in his opinion he felt a good
> individual unit for the 
> > plugs and equipment you wanted to protect was
> better than a whole house 
> > protector. He said many strikes, surges, etc. come
> into the house via 
> > phone lines, TV cable, satellite dishes, etc. and
> often bypass the whole 
> > house protector before getting into the home
> electrical system, which is 
> > why he prefers good single unit protectors when
> needed.
> Not to be argumentative, but it would seem that the
> peer-reviewed 
> transient protection literature doesn't agree with
> the single unit 
> protection philosophy.
> (i.e. things that aren't  sales material or field
> application guidelines 
> from one company or another.. but stuff that has
> been independently 
> produced, or at least reviewed by folks without a
> financial or other 
> interest.  Sure, the guys from Erico publish papers
> on transient 
> suppression, and Erico sells products that do this,
> but the journal's 
> pre-publication review process generally makes sure
> that 2 or 3 other 
> folks take a look at it and make sure it's not all
> bushwa.)
> Your friend is right that lots of transients come in
> other ways, which 
> is why you need protection on *all* of them, and why
> everyone is so 
> obsessed with all those "bonding" rules.  However,
> there's a whole raft 
> of reasons why protection at the entrance is needed,
> and preferred, and 
> which should be properly coordinated with the
> downstream protection.
> The guidelines for things like safety critical
> installations (e.g. the 
> FAA guidelines and DoD guidelines) all talk about
> transient protection 
> at the service entrance, but make little or no
> mention of "point of use" 
> protection.
> Also, a lot of protection devices get a lot of their
> protection ability 
> by absorbing the transient (and getting
> spectacularly destroyed in the 
> process).  I think I'd rather have the spectacular
> failure out by the 
> meter, rather than on some plugstrip behind the
> desk.
> Really, the only hazard that point of use protection
> protects against is 
> a transient being induced in your house wiring
> closer to the equipment 
> than to the service entrance, because of the time
> delays involved. 
> (transients from outside, which are MUCH more
> common, get suppressed at 
> the service entrance) Or, if you have something in
> your house that puts 
> big transients on the power wiring (like that 1kW
> tesla coil you fire up 
> in the garage.. been there, done that, cooked my
> garage door opener and 
> a UPS.)
>   Of course, a decent series mode suppressor (i.e. a
> LC low pass filter) 
> will solve that problem.  Most modern electronic
> equipment already has 
> fairly decent low pass input filters on the AC line
> connection (to 
> prevent signals inside the box from coming out and
> creating EMI havoc), 
> so the sub microsecond transient resulting from that
> spurious induced 
> voltage, and reflecting back from the clamp will get
> smoothed out by the 
> filter to a level that is lower than the damage
> threshold for your device.
> For folks wanting to spend some time and about $20,
> get the book by 
> Standler on overvoltage protection. (google standler
> overvoltage and 
> you'll probably find it) He's got all the data, the
> impulse waveforms, 
> the theory of what works and what doesn't.  His
> website also has some 
> info.  I can't recall which off hand, but in one
> place or the other, he 
> talks about the UL1449 standards, and the problem
> with "joule ratings" 
> and "clipping voltage".


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