PC form factor

From: Allison J Parent <allisonp_at_world.std.com>
Date: Thu Jul 8 16:57:36 1999

<This is only true for overhead lines, and not when they are buried under
<the street, correct? Actually, some of the main lines are fiber-optic now,
<which shouldn't carry a surge.

True to a point but, at some time the fiber becomes copper and there is
the source of risk.

A hit to a local tree can charge the ground that the copper passes through
and deliver a common mode bash to whatever is connected to it. Common
mode is when both leads are at the same potential but manyto many volts
above "Ground". This is very common with lightening. Shielded cable
is no help as the shield (at over 10,000 AMPS) can carry a very big
potential above around as well!

Keep in mind surge protectors are for small surges, lightining is a
very big surge and I've seen it melt 000 guage copper like it was
warm butter. The hit that did that cooked my NS* the first time
was a direct one to a roof antenna. the ground for that antenna was
000 copper. The second time that happend it was in a different place
and it hit the pole a half mile down thre road were it went underground
and though power and phone came in from underground... damm, not again!

Received on Thu Jul 08 1999 - 16:57:36 BST

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