Lightning Arrestor Questions
 

Hello:

The more I read up on this subject, the more confused I get.
Have some pretty basic questions on lightning protectors, if anyone has a
spare minute or two.
Would sure apprerciate any clarifications on the following points which I am
really confused on.

Will be putting up a simple receive only antenna once it warms up a bit
around here; probably a simple Inverted-L type, most likely the PAR EFL-SWL

Have been thinking about incorporating a lightning arrestor into the antenna
system Again, this is a receive only application.

The vertical leg of the antenna will terminate in the PAR Balun, which will
be pretty close to ground level. I will have a ground bar at that point to
which
the Balun ground(s) will be connected.

From the Balun to the radio will be coax.

Looking at the Polyphaser in line coax unit (dc blocked), and also the ICE
300 series units.

Questions:

a. For either unit, is the arrestor placed between the Balun and the
antenna, or between the Balun and the radio ? Why ?

b. The Polyphaser unit apparently, when triggered, shunts the charge (only)
to the coax shield. The only path to ground would then be up to the radio,
thru the
chassis, and then to the AC power ground.

Or, I guess, possibly back the other way via the Balun's ground ? Or both ?
I would also image that the Balun's windings would probably blow too quickly
to truly shunt any pulse to its ground ?

There doesn't seem to be any separate ground lug, like the ICE units
have from their pictures.

I'm a real novice with this lightning protection stuff, so I am
probably missing something, particularly with the Polyphaser
shunting-to-the-shield-only approach which
doesn't seem too great regarding how an adequate RF ground is reached for
any
diverted strike/pulse.

What am I missing or not considering with the Polyphaser approach ?
Thoughts on ?

c. Any opinions on the Polyphaser vs. the ICE units for a receiving only
application ?

Much thanks,
Bob

Lightning Arrestor Questions
 

"Robert11" bravely wrote to "All" (16 Jan 06 11:58:01)
--- on the heady topic of "Lightning Arrestor Questions"


A wire antenna will be instantly vaporised when directly struck by
lightning so the point is moot: you want to protect the equipment
inside, and the house inhabitants.

Asimov


Ro From: "Robert11"
Ro Xref: core-easynews rec.radio.amateur.antenna:222762

Ro Hello:

Ro The more I read up on this subject, the more confused I get.
Ro Have some pretty basic questions on lightning protectors, if anyone
Ro has a spare minute or two.
Ro Would sure apprerciate any clarifications on the following points
Ro which I am really confused on.
[,,,]

Lightning Arrestor Questions
 

Robert11 wrote:

Hello:

The more I read up on this subject, the more confused I get.

SNIPPED

Questions:

a. For either unit, is the arrestor placed between the Balun and the
antenna, or between the Balun and the radio ? Why ?

First, the comment in another response regarding direct strike is mostly
valid. No arrestor will protect from direct strike. [up to 100,000
amperes in less than 1 microsecond, with a 20,000 volt per meter E field.]

Second, for near strike, the arrestor should be installed depending on
arrestor design. For coax based designs installation should be between
balun and radio. For open wire design it should be installed at the wire
to balun interface. Near strike is a non precise technical term. For
near strike in the 10,000 E field zone the arrestor probably won't
provide the protection you seek. For the 1,000 E field zone you should
get some protection.

Why? When the arrestor ignites, fires, actuates there still is a voltage
across the arrestor. This is the net voltage from the plasma in the
spark gap or in the ionized internal gasses. This net voltage transient
has a power density that extends from BC/MF [160 meters] to the HF/VHF
boundary around 30 MHz. It is a broadband pulse. The question is how
much voltage can the radio be exposed to without damage?


b. The Polyphaser unit apparently, when triggered, shunts the charge (only)
to the coax shield. The only path to ground would then be up to the radio,
thru the
chassis, and then to the AC power ground.

Or, I guess, possibly back the other way via the Balun's ground ? Or both ?
I would also image that the Balun's windings would probably blow too quickly
to truly shunt any pulse to its ground ?

There doesn't seem to be any separate ground lug, like the ICE units
have from their pictures.

I'm a real novice with this lightning protection stuff, so I am
probably missing something, particularly with the Polyphaser
shunting-to-the-shield-only approach which
doesn't seem too great regarding how an adequate RF ground is reached for
any
diverted strike/pulse.

What am I missing or not considering with the Polyphaser approach ?
Thoughts on ?

c. Any opinions on the Polyphaser vs. the ICE units for a receiving only
application ?

Much thanks,
Bob


The best solution is to disconnect the antenna and move it away from the
radio when not in use.!!

I'm a retired Aerospace/Electrical engineer who spent years designing
for lightning strikes both direct and near strikes. My station is 100%
conforming to electrical code and lightning mitigation techniques. Last
July, a near strike lightning pulse caused the ground fault interruptors
for the pool, the bathroom and the kitchen to function. The circuit
breakers in the service panel for the basement power distribution
opened, and the power transformer on the utility pole about 1/2 mile
away exploded. I lost my ICOM 756 ProII which was disconnected from the
power lines, notebook computer, USB damage in a second computer on the
in-house LAN, and one telephone. The ICOM 756 Pro II was disconnected
from the antennas, and the lightning surge protectors did not actuate. A
post fault failure analysis indicated that there was a surge in the
utility power neutral to ground. The entire neighborhood of over 50
homes suffered some degree of damage. It is estimated by the power
utility that the strike was 1/2 mile away.

My ICOM 746, my Kenwood TM-G707, and the numerous power supplies
suffered NO damage. Go Figure :-)

CONCLUSION: Lightning finds way to kill electronics no matter how well
the equipment is installed.

Amoskeag Lightning Arrestor Questions
 

Hi

FYI, seems your email addr here dosn't work, if it's a real one

Dear Amos

i saw your post and hope you wouldn't mind if i asked you a quick
quesiton


Your Icom that was damaged, was unplugged from everything so how did
lightning 'get to it'??

I was kinda distrubed trying to figure it out


V sory to hear of your damage

ml


In article ,
Amos Keag wrote:

Robert11 wrote:

Hello:

The more I read up on this subject, the more confused I get.

SNIPPED

Questions:

a. For either unit, is the arrestor placed between the Balun and the
antenna, or between the Balun and the radio ? Why ?

First, the comment in another response regarding direct strike is mostly
valid. No arrestor will protect from direct strike. [up to 100,000
amperes in less than 1 microsecond, with a 20,000 volt per meter E field.]

Second, for near strike, the arrestor should be installed depending on
arrestor design. For coax based designs installation should be between
balun and radio. For open wire design it should be installed at the wire
to balun interface. Near strike is a non precise technical term. For
near strike in the 10,000 E field zone the arrestor probably won't
provide the protection you seek. For the 1,000 E field zone you should
get some protection.

Why? When the arrestor ignites, fires, actuates there still is a voltage
across the arrestor. This is the net voltage from the plasma in the
spark gap or in the ionized internal gasses. This net voltage transient
has a power density that extends from BC/MF [160 meters] to the HF/VHF
boundary around 30 MHz. It is a broadband pulse. The question is how
much voltage can the radio be exposed to without damage?


b. The Polyphaser unit apparently, when triggered, shunts the charge (only)
to the coax shield. The only path to ground would then be up to the radio,
thru the
chassis, and then to the AC power ground.

Or, I guess, possibly back the other way via the Balun's ground ? Or both ?
I would also image that the Balun's windings would probably blow too quickly
to truly shunt any pulse to its ground ?

There doesn't seem to be any separate ground lug, like the ICE units
have from their pictures.

I'm a real novice with this lightning protection stuff, so I am
probably missing something, particularly with the Polyphaser
shunting-to-the-shield-only approach which
doesn't seem too great regarding how an adequate RF ground is reached for
any
diverted strike/pulse.

What am I missing or not considering with the Polyphaser approach ?
Thoughts on ?

c. Any opinions on the Polyphaser vs. the ICE units for a receiving only
application ?

Much thanks,
Bob


The best solution is to disconnect the antenna and move it away from the
radio when not in use.!!

I'm a retired Aerospace/Electrical engineer who spent years designing
for lightning strikes both direct and near strikes. My station is 100%
conforming to electrical code and lightning mitigation techniques. Last
July, a near strike lightning pulse caused the ground fault interruptors
for the pool, the bathroom and the kitchen to function. The circuit
breakers in the service panel for the basement power distribution
opened, and the power transformer on the utility pole about 1/2 mile
away exploded. I lost my ICOM 756 ProII which was disconnected from the
power lines, notebook computer, USB damage in a second computer on the
in-house LAN, and one telephone. The ICOM 756 Pro II was disconnected
from the antennas, and the lightning surge protectors did not actuate. A
post fault failure analysis indicated that there was a surge in the
utility power neutral to ground. The entire neighborhood of over 50
homes suffered some degree of damage. It is estimated by the power
utility that the strike was 1/2 mile away.

My ICOM 746, my Kenwood TM-G707, and the numerous power supplies
suffered NO damage. Go Figure :-)

CONCLUSION: Lightning finds way to kill electronics no matter how well
the equipment is installed.

Amoskeag Lightning Arrestor Questions
 

"ml" bravely wrote to "All" (18 Jan 06 01:59:16)
--- on the heady topic of "Amoskeag Lightning Arrestor Questions"

ml From: ml
ml Xref: core-easynews rec.radio.amateur.antenna:222810

ml Hi

ml FYI, seems your email addr here dosn't work, if it's a real one

ml Dear Amos

ml i saw your post and hope you wouldn't mind if i asked you a quick
ml quesiton


ml Your Icom that was damaged, was unplugged from everything so how did
ml lightning 'get to it'??

ml I was kinda distrubed trying to figure it out


I'm guessing his radio was most likely damaged from EMP. An
acquaintance had a direct hit on his tower and even his tv's remote
control fried.

A*s*i*m*o*v

Amoskeag Lightning Arrestor Questions
 

ml wrote:

Hi

FYI, seems your email addr here dosn't work, if it's a real one

Dear Amos

i saw your post and hope you wouldn't mind if i asked you a quick
quesiton


Your Icom that was damaged, was unplugged from everything so how did
lightning 'get to it'??

I was kinda distrubed trying to figure it out
\

Ground Loop. Took time to find it though.

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.] Although everything on the operating table was isolated from
the utility power and external antennas, everything was connected
together by coax braid, connections to the operating position common
'ground', and the 13.8 volt return.

Remember, this strike caused large area damage. Close to 50 homes
suffered some damage. Several homes took up to 6 weeks to have their
internet functioning again.

The lightning strike tripped all [ALL] ground fault interruptors in the
house. The ground loop in my system connected chassis and power returns
and coax cable together. The weak link were circuit boards in my 756 Pro
II filter and tuner. The boards VAPORIZED. Smoke all over the place.
Pungent smell, etc. That failure protected my IC-746, Kenwood TM-G707,
etc from damage. [Expensive fuse!!]

I wonder if it also protected my swimming pool pump and heater from
damage grin?

Amoskeag Lightning Arrestor Questions
 

On Wed, 18 Jan 2006 08:24:40 -0500, Amos Keag
wrote:

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.]

You've tweaked my curiosity what does the military do?

73
Danny, K6MHE




email: k6mheatarrldotnet
http://www.k6mhe.com/

Amoskeag Lightning Arrestor Questions
 

On Wed, 18 Jan 2006 07:18:57 -0800, Dan Richardson wrote:

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.]

You've tweaked my curiosity what does the military do?

Hi Dan,

They use ground as a shield, not a current carrier. This is also
suppose to be code for commercial and retail electronics devices.
Connecting the metal cabinet to neutral was supposed to have slipped
into La Brea tarpits with the dinosaurs. Back before polarized plugs,
you could electrocute yourself by guessing wrong, touching the metal
surface and also being grounded. The bridging between toasters and
water taps (or stove tops or fridges) come to mind.

Also common, but nearly as fatal, was the practice of putting two,
series capacitors across the AC line into receivers to cut down on
noise from the lines. They would also take the tap of the two caps
and tie that to the chassis, thus insuring half the line potential was
always on its surface, unless you provided a ground connection. This
was one of those suicide connections where if you were holding the
chassis and pulled the ground lead, you automatically became a fried
line fuse. Members of our hobby have preserved this suicide
connection by grounding their remote antenna (or equipment) through
the coax shield instead of through a separate ground wire (this is why
we have codes).

GFI breakers sense the common mode current (that current that has
escaped the neutral/hot loop) on the shield path (although it is
called a safety ground for 60Hz service).

73's
Richard Clark, KB7QHC

Amoskeag Lightning Arrestor Questions
 

Asimov wrote:
"An acquaintance had a direct hit on his tower and even his tv`s remote
control head."

Did he hear a voice boom from the clouds saying: "Dammit! Missed
again!"?

A good tower ground should mitigate lightning`s fiversion through a TV
remote control. But, I`ve seen stories of "ball lightning" chasing about
inside a house.

Best regards, Richard Harrison, KB5WZI

Lightning Arrestor Questions
 

Robert 11 wrote:
"For either unit is the arrester placed between the Balun and the
antenna, or between the Balun and the radio? Why?

It likely is superflous.

Coax connectors make lightning arrestors of sorts. They clamp voltage to
the arc sustaining voltage (less than 100 volts), once they fire. If you
are transmitting, r-f may keep the arc alive. Broadcast transmitters
sense the arc and shut the transmitter down for an instant to quench the
arc. Communications radios usually don`t bother as their transmissions
are sporadic and usuallly short.

Remember, coax shield is impenetrable to r-f. D-C conducts right
through. R-F does not due to skin effect.

In countless VHF antenna installations atop tall towers around rhe world
we never used a Polyphaser or similar arrestor on the coax, yet never
had damage to radio antenna circuits, even to transistorized radios.

We always used folded driven antenna elements. We grounded the coax at
the top and bottom of the antenna tower. The tower due to its size has
lower surge impedance and carries the bulk of the lightning current to
ground. The tower is well grounded.

We found it necessary to use brute-force pi-filters on every power wire
feeding the radio including the neutral wire. We used tower lighting
chokes in the pi-filters to cary the current required to power the
radios. We shunted the filter inputs and outputs to ground with MOV`s
(across the a-c capacitors).This limited surge voltage on the radio and
on the powerline. It eliminated all damage to the power supplies in the
radios. These filters were found necessary only when transistor radios
were introduced. Before that, the grounded antenna system sufficed for
tube-type radios.

Best regards, Richard Harrison, KB5WZI

Amoskeag Lightning Arrestor Questions
 

In article ,
Amos Keag wrote:

Ground Loop. Took time to find it though.

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.]

*yoicks*!

The latter, I can believe is common practice.

The former - tying the powerline neutral directly to the case -
strikes me as being *extremely* contrary to electrical code and common
sense. It'd turn the supply into a deathtrap-waiting-to-happen if it
were plugged into an outlet having the hot and neutral reversed... and
these are (alas) not at all uncommon.

Now, having the utility power safety ground wired directly to the
case, I can very well believe... this is quite common.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Amoskeag Lightning Arrestor Questions
 

Dan Richardson wrote:

On Wed, 18 Jan 2006 08:24:40 -0500, Amos Keag
wrote:


The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.]


You've tweaked my curiosity what does the military do?

73
Danny, K6MHE

The general no pun intended Military design requirement is the the
equipment cases carry no intentional or credible fault currents.
[Therefore no inadvertant shocks, in MIL STD terminolgy no personnel
RISK, from a hot chassis]. [RISK is assign for personnel, HAZARD for
equipment]. Accordingly, the cases and circuit returns are isolated
typically by a 500K resistor. There is one system ground point, not a
distributed grounding system.

RF circuit design includes isolation between onbly for the output from
the low level circuits. Coax shields, shielding on shielded
circuits/wires carry no intentional currents and to the maximum extent
possible no fault currents.

Example: the output stages of a 5 GHz telemetry transmitter is on a
circuit board that is physically isolated from the low level stages and
the power source. The isolation may be either capacitive or inductive
coupled; in my last design [c.a. 1986] we used 1/4 wave stubs on the
same board, top circuit to bottom circuit, woking against two separate
returns [top surface base copper versus bottom surface base copper]

In the Nuclear safe environment for example, the primary and secondary
of power transformers MUST be 100% isolated and each winding separately
shielded with the shields connected independently to the chassis.
Therefore a transformer short circuit on the primary cannot propagate
through to the secondary. Or, a primary short to chassis cannot
propagate to the secondary. And the design MUST include 100% absolute
disconnect from primary power in the event of a transformer failure or
power out of spec condition. The requirements go on and on and on ...

Bottom line, equipment cases carry no current, share no current carrying
path [exception is RF output stages only].

So, the ASTRON RS 35 is not suitable for MIL usage. Now the ASTRON
becomes 100% MIL suitable with the removal of just one [1] jumper in the
supply [the connection from 13 volt return to chassis. The secondary of
the PS is 100% isolated from the primary and the regulator circuits are
100% isolated from chassis]. But, the ICOM radios being powered also
violate the MIL requirements and corrupt the system. Remember, HAM
equipment is generally operated in COMMERCIAL circuits and must comply
with local electrical codes.

Amoskeag Lightning Arrestor Questions
 

Sorry your email address dosn't work but thanks for clarifing the
hookup i must have missread the original statement you made whereby i
thought you said the pro was completely disco i totally understand if
it had anything connected that explains it!!

however you confused me more so, now that you said the pro getting fried
somehow 'saved' your other gear from being damaged... i can't see how
that happened unless you feel the rig it self actually absorbed ALL the
energy i presume the odds of that are slim

so can you help unconfuse me??

and it was great to read about how the mil does stuff pretty cool

again sorry about your damage hope you had arrl rig insurrance


m



In article ,
Amos Keag wrote:

ml wrote:

Hi

FYI, seems your email addr here dosn't work, if it's a real one

Dear Amos

i saw your post and hope you wouldn't mind if i asked you a quick
quesiton


Your Icom that was damaged, was unplugged from everything so how did
lightning 'get to it'??

I was kinda distrubed trying to figure it out
\

Ground Loop. Took time to find it though.

The Astron RS-35 power supply connects utility power neutral to the
case. It also connects the 13.8 volt return to the case. [This is
commercial common practice but is prohibited in Military Systems
design.] Although everything on the operating table was isolated from
the utility power and external antennas, everything was connected
together by coax braid, connections to the operating position common
'ground', and the 13.8 volt return.

Remember, this strike caused large area damage. Close to 50 homes
suffered some damage. Several homes took up to 6 weeks to have their
internet functioning again.

The lightning strike tripped all [ALL] ground fault interruptors in the
house. The ground loop in my system connected chassis and power returns
and coax cable together. The weak link were circuit boards in my 756 Pro
II filter and tuner. The boards VAPORIZED. Smoke all over the place.
Pungent smell, etc. That failure protected my IC-746, Kenwood TM-G707,
etc from damage. [Expensive fuse!!]

I wonder if it also protected my swimming pool pump and heater from
damage grin?

Amoskeag Lightning Arrestor Questions
 

"Richard Harrison" bravely wrote to "All" (18 Jan 06 12:17:51)
--- on the heady topic of "Amoskeag Lightning Arrestor Questions"

RH From: (Richard Harrison)
RH Xref: core-easynews rec.radio.amateur.antenna:222822

RH Asimov wrote:
RH "An acquaintance had a direct hit on his tower and even his tv`s
RH remote control head."

There seems to be a problem with the compression. I wrote "remote
control fried." not "head."!


RH Did he hear a voice boom from the clouds saying: "Dammit! Missed
RH again!"?

RH A good tower ground should mitigate lightning`s fiversion through a TV

What is a "fiversion"... ah "diversion", right! Damn that compressor
is F&^^%$@@**


RH remote control. But, I`ve seen stories of "ball lightning" chasing
RH about inside a house.

That is what he said. Briefly saw a fireball wizz around the room.

A*s*i*m*o*v

Amoskeag Lightning Arrestor Questions
 

Dave Platt wrote:

SNIPPED

*yoicks*!

The latter, I can believe is common practice.

The former - tying the powerline neutral directly to the case -
strikes me as being *extremely* contrary to electrical code and common
sense.

It happens at the service panel! White [COMMON] is connected to the non
current carrying bare wire at a many input terminal block. The block is
then connected to an 8 foot ground rod installed by the utility or your
electrician.

It'd turn the supply into a deathtrap-waiting-to-happen if it
were plugged into an outlet having the hot and neutral reversed... and
these are (alas) not at all uncommon.

Agree, I found three miswired circuits in this house. I was present at
the house inspection and ran the tests myself. The mis-wiring was
corrected the day we moved in. [Radio Shack sells a simple tester for
this. It is worth checking every circuit in your house or apartment].


Now, having the utility power safety ground wired directly to the
case, I can very well believe... this is quite common.

Maybe my terms are not up to date.

My electrical service connection is 3 wire 240 volts AC at 60 Hz. Within
the distribution panel RED is connected to one feed; BLACK is connected
to the other feed and white is connected to the common connection
[return]. The common connection is then distributed throughout the house
as the bare wire in standard wiring. The common, white and return,
connection is connected to an external earth connection [ground] by an 8
foot ground rod.. So, the WHITE wire serves as return for both RED and
BLACK circuits and has a single earth connection. So, your 3 prong
socket contains connections to power as follows: HOT [either RED or
BLACK] circuit, RETURN [WHITE] and GREEN [GROUND] [supposedly zero
current carrying. A GFI works on this part of the connection].

In the ASTRON RS 35 the primary wiring has the GREEN connected to the
chassis. The BLACK/WHITE go to the transformer primary. This is fine.

The secondary, transformer isolated, has the 13.8 volt return connected
to the chassis. It is now possible for the chassis to become part of the
current carrying circuit, 13.8 volt return to utility WHITE wire to
groud wire. The 13.8 volt return now runs to the ICOM 756 Pro II, ICOM
746 and Kenwood TM-G707. The cases of the three radios and the ASTRON
are connected to a common return on the operating table [1/2 inch copper
pipe that connects directly to the service panel common return/ground
point]. The cases of the three radios are connected together by the
braid on the various lengths of coax and the 13.8 volt return. ERGO, a
ground loop among the 13.8 volt return, the coax braid, equipment cases
and the utility ground.

With a nearby lightning strike that blew the utility 3 phase transformer
and affected approximately 50 consumers there are several possible
causes of trouble. Among these are imbalance in utility service [i.e.
the 240 into the house becomes seriously imbalanced] a lightning induced
magnetic transient that couples to all ground loops, or my system was
still connected to antennas and power.

I had ALL connections to antennas and power plugs removed except the 1/2
inch copper pipe earth connection at the service panel. My neighbors
lost garage door openers, multiple tv sets, numerous telephone circuits,
numerous internet circuits, COMCAST had to rewire approximately 1/4 mile
of cable tv in front of the house, several homes lost expensive stereo
and sound lab setups. In my house all ground fault interuptors
activated. And two circuits in my PRO II exploded to charcoal with dust
and stench. The LAN blew up, and one computer was lost.

My station was the equivalent of being mounted on a copper sheet, each
chassis connected to the copper sheet with bond wires, the 13.8 VDC
return connected to the copper sheet [making a loop into the circuits]
and the copper sheet was/is directly connected to earth/ground at the
power utility panel.

Since I was not connected to POWER or antennas, and the connection to
utility common and earth ground are installed to code [circa 1978], I
concluded a ground loop that I subsequently found and measured [after
the fact of course] was the susceptibility.

Conclusion: Nearby or direct strike lightning causes havoc. Solution:
have good insurance. I recovered replacement costs for all except the
depreciated computer. I have a specific INSURANCE SCHEDULE on my radio
and camera equipment.

Amoskeag Lightning Arrestor Questions
 

In article ,
Amos Keag wrote:
Maybe my terms are not up to date.

My electrical service connection is 3 wire 240 volts AC at 60 Hz. Within
the distribution panel RED is connected to one feed; BLACK is connected
to the other feed and white is connected to the common connection
[return]. The common connection is then distributed throughout the house
as the bare wire in standard wiring. The common, white and return,
connection is connected to an external earth connection [ground] by an 8
foot ground rod.. So, the WHITE wire serves as return for both RED and
BLACK circuits and has a single earth connection. So, your 3 prong
socket contains connections to power as follows: HOT [either RED or
BLACK] circuit, RETURN [WHITE] and GREEN [GROUND] [supposedly zero
current carrying. A GFI works on this part of the connection].

In the ASTRON RS 35 the primary wiring has the GREEN connected to the
chassis. The BLACK/WHITE go to the transformer primary. This is fine.

Yes, that's all fine, and per code.

In US wiring terminology, the green wire is "ground". It's present
entirely for safety purposes - it's not supposed to carry any current
back to the panel during normal operation. It carries current only
in the event of a fault. It's what the external chassis should be
tied to, for metal-chassis equipment with a three-wire cord.

Black is "hot". I'm told that this color was chosen because black is
traditionally the color of death.

White is "neutral". It's the current return for the hot supply. It
should never be tied to the chassis, for two reasons:

[1] The occasional hot/ground reversal thanks to an mistake in the
house wiring. You really don't want your chassis floating at 120 VAC
above local ground.

[2] The neutral pin at the outlet can be pulled several volts above
ground voltage, if some load on that circuit is drawing a healthy
number of amperes, due to I^2*R drop in the house wiring. If the
chassis were tied to neutral, and this occurred, someone might
manage to get a shock if they touched both the chassis and a
truly-grounded pipe or wire.

With a nearby lightning strike that blew the utility 3 phase transformer
and affected approximately 50 consumers there are several possible
causes of trouble. Among these are imbalance in utility service [i.e.
the 240 into the house becomes seriously imbalanced] a lightning induced
magnetic transient that couples to all ground loops, or my system was
still connected to antennas and power.

I had ALL connections to antennas and power plugs removed except the 1/2
inch copper pipe earth connection at the service panel. My neighbors
lost garage door openers, multiple tv sets, numerous telephone circuits,
numerous internet circuits, COMCAST had to rewire approximately 1/4 mile
of cable tv in front of the house, several homes lost expensive stereo
and sound lab setups. In my house all ground fault interuptors
activated. And two circuits in my PRO II exploded to charcoal with dust
and stench. The LAN blew up, and one computer was lost.

Ouch! My condolences!

When a strike of that magnitude occurs nearby, I have a feeling that
the Law of Chaos prevails. The current will do whatever it (censored)
well wants to. Even some equipment which is entirely unplugged might
take enough of a pulse via induction to suffer some damage to
sensitive components.

Glad to hear that you managed to recover the cost of replacement!

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Lightning Arrestor Questions
 

Peak current of 100,000 A for 1 microsecond in wire with resistance of
(say) one ohm gives energy of 10,000 Joule.

If the wire is No. 12, that would warm it up pretty well, but vaporize?

Where have I gone astray?

TIA

Chuck

Lightning Arrestor Questions
 

chuck wrote:

Peak current of 100,000 A for 1 microsecond in wire with resistance of
(say) one ohm gives energy of 10,000 Joule.

If the wire is No. 12, that would warm it up pretty well, but vaporize?

Where have I gone astray?

TIA

Chuck

So far, correct. But, that 10,000 J equates to 1E16
[100,000,000,000,000,000] watts peak power.

There is a thermal shock wave that occurs in the wire. There is a
transient magnetic wave in the wire.

The failure mechanism has been empirically correlated to peak power
times [pulse width^1/2].

The wire, or portions of it goes away!!