On Oct 23, 12:00 am, w_tom <w_t...@[EMAIL PROTECTED]
> wrote:
> On Oct 22, 1:48 am, David <inva...@[EMAIL PROTECTED]
> wrote:
>
> > 3) ... if there is a close by or direct lightning hit, then all of
th=
e
> > electrical wiring, including the sensor wires for the alarm system,
> > will now become antennas that will attract arcing or inductive surge
> > loadings.
>
> Don't worry about fields from a nearby strike. Such 'damage' is
> promoted by myths and speculation.
..
Francois Martzloff was the NIST guru on surges and wrote the NIST
guide along with many published technical papers.
Martzloff was involved in an investigation that included an insurance
company and a power utility that took a very limited look at equipment
damaged by surges. One of the cases was a multichannel audio amplifier
that had several channels damaged by a very near lightning strike that
was picked up on speaker wires.
From the NIST guide:
=93Surges of a slightly different kind can also happen in parts of other
electrical systems that do not directly involve a power line. Examples
of these are: the antenna for a remote garage door opener, the sensor
wiring for an intrusion alarm system.... Surges in these systems are
caused by nearby lightning strikes.=94
And:
=93Intruder alarm systems using wires between sensors and their central
control unit can be disturbed - and damaged in severe cases - by
lightning striking close to the house. The wires necessary for this
type of installation extend to all points of the house and act as an
antenna system that collects energy from the field generated by the
lightning strike, and protection should be included in the design of
the system, rather than added later by the owner=94
Direct pickup is very low concern compared to surges coming in on
utility wires.
--
bud--
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