Jack Painter wrote:
"Here is where you are mixing apples and oranges=A0because ground loops
and lightning protection are not related."

A ground loop is a potentially detrimental condition due to two or more
points in an elewctrical system that are nominally at ground potential
being connected by a conducting path.

A ground loop may provide a common impedance which couples energy
between two or more circuits. Strength of the energy in the electrical
circuits is immaterial in a current loop so long as nothing breaks down.
Response to the excitation is the same.

A lightning strike is a huge noise injection. Techniques for noise
reduction and testing are
also applicable to lightning suppression and may be tested with weak
noise signals. I know from personal experience.

It is desirable to avoid common impedances which can couple lightning
from one circuit to another, as a "ground loop" may.

Ground connections for protected equipments can be made with individual
wires between each of the devices and a common ground point to avoid
ground loops. This is not always practical.

It is usually practical to enclose devices inside a conductive
enclosure, then to low-pass filter and surge protect every wire which
penetrates the enclosure.

A screened room can serve as both noise and lightning protection, for
example.

Best regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote
Jack Painter wrote:
"Here is where you are mixing apples and oranges because ground loops
and lightning protection are not related."
--
A ground loop is a potentially detrimental condition due to two or more
points in an elewctrical system that are nominally at ground potential
being connected by a conducting path.

Ground connections for protected equipments can be made with individual
wires between each of the devices and a common ground point to avoid
ground loops. This is not always practical.

It is usually practical to enclose devices inside a conductive
enclosure, then to low-pass filter and surge protect every wire which
penetrates the enclosure.
--

Hi Richard, had I thought that was a controversial statement, I could have
elaborated that elimination of ground loops is normally a radio frequency
interference issue, and the creation of at least one ground loop is a design
requirement in residential lightning protection. The two are not usually
discussed together unless a conflict ocurrs, but I see your point.

It is indeed a requirement to individually bond equipment to the single
point station ground...and yes, practicality allows certain clusters of
equipment to be common bonded within their enclosures as you commented. But
the one place where a ground loop *must* be installed is in the station
ground to electrical service ground bonding. Proper station design requires
these never be far apart from each other in the first place, but we are
talking about residential stations, and close proximity between them is
rarely possible.

Telecom stations that cannot individually bond thousands of cards or even
hundreds of racks use high voltage isolation transformers and/or fiber optic
isolation from station ground entirely. Residences typically have neither
close proximity to AC service ground, not the financial ability to utilize
fiber or other HV isolation, so living with at least one ground loop is a
requirement. This has been reported to cause problems in some zero-volt
ground reference computing equipment, and isolated grounding is authorized
under certain conditions for that case only. I have not seen comments about
radio frequency interference from ground loop(s) caused by lightning
protection design. If they occur, perhaps they are easily choked with
standard RF control devices. I use those extensively anyway, so maybe that
chokes any ground loop problem, if one ever existed.

Thanks for your comments as always,

Jack