[Elecraft] Lightning Protection (was-Re: suggested PC???)

Wed Jan 6 18:43:08 EST 2016

As Fred mentioned, MOVs gradually fail.  And the failure mechanism is a 
gradual reduction of the "trigger voltage".  As the trigger voltage 
slowly drops, the MOVs start disappating power at the very peak of the 
AC line voltage.  If you are lucky, you find a warm device.  But most 
often they fail sight-unseen.  Once in a while if installed in a plastic 
"outlet extender", they start a fire. Beware.

John  AF6QO

On 1/6/2016 3:28 PM, Fred Townsend wrote:
> I would disagree with the use of MOVs at the service entrance unless there are inductors preceding.
>
> The key words in this discussion are protection systems. There is no one component or silver bullet that will protect all. The chances are if you take a direct strike there will be damage so unplugging is still a good idea. You would like any damage to be to cheap things like surge protectors that are  easily replaced. Having said that MOVs are cheap but they are not lighting protectors so it is foolhardy to build your principle lightning defense around them. For those wondering a surge is like when the secondary power line falls down on the low voltage line or a lightning strike AFTER the leading edge of the wave front is diminished. In short MOVs work in milliseconds. The leading edge of a lightning burst is in the microsecond range. Transorbs, gas protectors, capacitors, and carbon protectors are shunting devices in networks that work in the microsecond range and can be used at the service entrance.
>
> Series Inductance is a great way to knock off the leading edge but absolutely defeats your protection system when used in the grounding system or green wire. Remember ALL conductors have inductance so shorter is better. Never coil or square a ground wire.
>
> Maintenance of protection systems is essential too. Transorbs and carbons fail shorted. For this reason VDE sometimes requires these type components to be protected by fuses as well.  Gas protectors and MOVs fail open. MOVs fail gradually too. Capacitors and inductors take physical damage too and can fail either open or shorted. After your big lightning storm these components should be inspected and replaced if you see black smudges on or around them. MOVs will physically deteriorate and are easy to spot defective ones.
>
> 73,
> Fred, AE6QL
> -----Original Message-----
> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim Brown
> Sent: Wednesday, January 6, 2016 1:35 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Lightning Protection (was-Re: suggested PC???)
>
> YES!
>
> Another VERY important thing is to NEVER use "MOV surge protectors" on branch circuits. They're great at the service entrance, as Bob recommends, but they CAUSE equipment damage when used on branch circuit, because the MOVs dump the lightning spike onto the Green wire, which creates a high voltage spike on the Green wire. That voltage is different at every outlet and at every piece of gear, and the difference shows up as a common mode voltage between interconnected equipment.
> THAT'S what blows up stuff connected by wired Ethernet.  We discovered this the hard way about 25 years ago in the pro audio industry.
>
> The ONLY safe surge protectors on branch circuits (that is, next to
> equipment)  are SERIES MODE protectors. They work by storing the surge in a big inductor, then slowly discharging it. They're more expensive, but they won't blow up your gear. The only mfrs I know of are Brick Wall, Zero Surge, and SurgeX.
>
> Also critical -- bond ALL grounds together, including the shack ground, CATV ground, TELCO ground, etc., and back to the power ground.
>
> 73, Jim K9YC
>
>
> On Wed,1/6/2016 11:35 AM, Bob McGraw K4TAX wrote:
>> Two things I've found to be a big deterrent regarding lightning damage:
>>
>> (a) all driven grounds must be bonded back to the AC mains ground and
>> this must be done outside of the house.   I use some 1/2" flexible
>> copper water line as my bonding conductor.  It is trenched around the
>> outside of the foundation about 6" deep from the tower ground and coax
>> lightening protection system back to the AC Mains ground some 50 ft away.
>>
>> (b)  Install a whole house surge protector at the main breaker panel.
>> These are sometimes referred to as Secondary Surge Protectors.
>> Usually should be installed by a qualified licensed electrician.
>>
>> 73
>> Bob, K4TAX
>>
>>
>> On 1/6/2016 11:52 AM, Barry Baines wrote:
>>> Neil:
>>>
>>>
>>>> On Jan 6, 2016, at 8:25 AM, Neil Zampella <neilz at techie.com> wrote:
>>>>
>>>> FWIW ... I've got everything setup wired in the shack, but
>>>> everything (cable coax, ethernet, power) runs through an
>>>> uninterruptible power supply (ups).   Many of the higher end models
>>>> provide not only power surge protection and battery, but
>>>> lightning/surge protection for coax and ethernet.
>>> By ‘coax’ do you mean cable TV coax or are you suggesting RF coax for
>>> amateur radio transceivers?  Clearly, UPS surge protection is not
>>> designed for anything on the order that an amateur transmitter (even
>>> QRP) can produce.  Further, UPS devices presume 75 ohm coax systems,
>>> not 50 Ohm as used in amateur radio antennas and transmitters. They
>>> are designed to protect a TV antenna or a cable setup box/cable modem.
>>>
>>> My shack in Georgia was impacted by an indirect hit in 2014 which
>>> damaged computers, amplifiers, ethernet switches, and a myriad of
>>> gear that was ’networked’ in the shack as well as the house, even
>>> though I have Polyphasers on all of my RF cables going into the shack
>>> from the tower with an extensive ground system for lightning surges.
>>> What I didn’t have was adequate protection on my ethernet, coax from
>>> DirecTV, and telco lines in the shack where presumably the surge
>>> entered.  I didn’t want to go wireless on the LAN because I operate
>>> my station remote and wireless connections introduce a potential
>>> failure point that can’t be fixed unless I’m there to reset
>>> something.  Wireless is also slower than wired ethernet.
>>>
>>> My solution was to purchase Ethernet-to-Fiber converters to isolate
>>> my LAN network in the shack from the rest of the LAN in the house as
>>> well as provide isolation from individual components from one
>>> another. Thus, I ran dual 110 ft. fiber from the house to the
>>> hamshack (through existing buried conduit that also carries telco and
>>> DirecTV) that will keep surges from coming into the house through the
>>> ethernet connections from the shack.  I installed switches in the
>>> shack that have both LAN and Fiber so that I could isolate nearby
>>> components from the network in the shack.  I use ethernet-to-fiber
>>> converters with short fiber jumpers to individually isolate my high
>>> end equipment from the network (such as a  Flex-6700 and the
>>> computers in the shack).  These converters have no impact on the
>>> ability of the network to communicate (still 10/100/1000 MB depending
>>> upon the component that it protects).  I consider this an insurance
>>> policy—the cost of the fiber being significantly less than the cost
>>> of replacement of damaged equipment. Each converter has a 5V ‘wall
>>> wart’ which is plugged into a UPS primarily for surge protection but
>>> also keeps the network up in the event of power failure or momentary
>>> power fluctuation.
>>>
>>> I’m still in the process of installing protection for the DirecTV
>>> line coming to the shack as well as the telco lines in the shack.  I
>>> have a central ground panel where I will install the protective
>>> devices for telco and DirecTV by the existing RF surge protectors.
>>> One challenge is finding a lightning protection device for DirecTV as
>>> they feed power through the cable to power the LNB at the dish.  When
>>> I spoke with a DirecTV technician, he had no suggestions on what to
>>> use.  There are devices out there, just need to find them.  I also
>>> have a Speco Technology PTZ analog camera on the tower with 75 ohm
>>> video, 12 VDC power, and RS-485 control lines will also be protected
>>> at the same ground panel.  I’ve found suitable devices for the
>>> camera’s connections.
>>>
>>> AC power is also a concern.  A UPS is adequate for 120 VAC equipment
>>> such as computers and monitors but won’t protect 220 VAC devices such
>>> as high power amplifiers.  I’m still hoping to find a suitable surge
>>> protector designed for 220 VAC systems to plug between my amplifiers
>>> and the 220 VAC wall connection.
>>>
>>>   From an Elecraft perspective, I use fiber-to-ethernet interfaces
>>> between the Remote Rig devices and my network.  Thus, if a surge were
>>> to go from the K3’s RS-232 port to the RemoteRig RCC-1258MKII, the
>>> surge won’t be extended through the Remote Rig to the LAN.  My
>>> KPA-500 is attached to a RC-1216H (which provides a web interface for
>>> controlling the amplifier) which in turn has a ethernet-to-fiber
>>> interface which protects the network from a surge coming through the
>>> RC-1216H.  My KAT-500’s serial line is attached to a Lantronix
>>> Serial-to-Ethernet interface device which in turn is attached to an
>>> ethernet-to-fiber interface.  As my rotor controller RS-232 line is
>>> attached to the same Lantronix box, any surge coming from the rotor
>>> interface will also not go through the LAN network. Thus, there are
>>> no RS-232 line connections directly from my ham equipment to a
>>> computer, providing additional isolation for the computers.  I can’t
>>> say the same thing about USB connections, as some devices such as a
>>> Fun Cube Dongle won’t work if attached to a USB-to-Ethernet
>>> interface.  However, I do use a USB-to-Ethernet device for my
>>> Wavenode WN-2.
>>>
>>> 73,
>>>
>>> Barry Baines, WD4ASW
>>> Westborough, MA
>>> Folkston, GA
>>>
>>>
>>>> Neil Zampella
>>>> KN3ILZ
>>>>
>>>> On 1/5/2016 8:14 PM, Gary K9GS wrote:
>>>>> Hi Jerry,
>>>>>
>>>>> Don't use a wired network.  I had my shack computer on a wired
>>>>> network when I took a lightning hit a couple of years ago.
>>>>>
>>>>> Everything connected on the wired network was zapped (2 PCs,
>>>>> router, modem, K3 RS-232 port, WinKey (connected to one of the
>>>>> PCs), and the Cable TV amplifier located over 150 ft away out by
>>>>> the road.  When I rebuilt everything i went wireless with all of my
>>>>> PCs and have never regretted it.
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>>
>>
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