Caveat on Fiber cables, most of them have a steel strength member down th e
center of them which most often is grounded, still there have been many
occcasions when lightning has hit near a buried fiber where it has
propigated through the soil and fractured the glass from the heat generated
flowing down the strength member. Many brands of newer Fiber Cables use
Kevlar for a strength member in order to mitigate this problem somewhet.
This has happend to cables buried as deep as 4 feet in sandy soil. One of
the larger common carriers who routes their fiber over our territory had to
abandon one of their routes due to excessive service outages in spite of
state of the art grounding and protection methods. Even glass isn't proof
positive when it comes to lightning, the best protection method of all is
ground everything outside and disconnect the cables coming inside.
73's
Dave
wa4emr
At 01:39 PM 5/30/98 -0500, RICHARD L OWENS wrote:
>Some time ago, I talked with an old friend in the electric power
>business. He told me that they have been abandoning microwave, formerly
>used in the control and monitoring of their HV transmission lines, in
>favor of fiber optics. The fiber is strung in the aerial ground line, at
>the top of all towers. I was surprised, and asked about lightning
>strikes. He told me that aside from the cases where the strike severs
>the line itself, they never see any disruption in their communications.
>I know this is not directly related to the original question, but it may
>give some insight into how non-metallic lines react to lightning.
>73, Richard Owens, K9OFG
>
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