From: Jason Tang
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Subject: Re: Info on protecting UTP network / phone / AC mains so lightning
on cable doesn't destroy everything (again)?
Date: Tue, 05 Nov 2002 13:01:21 GMT
NNTP-Posting-Date: Tue, 05 Nov 2002 08:01:21 EST
Tony (remove \"_\" from email address) wrote:
> Hi all,
> I'm just getting back on air after lightning somehow got into my cable and blew
> out my cable modem, NIC, printer, CDRW, related ports etc (PC still goes except
> for the lost ports, but who knows for how long). It seems dozens of neighbours
> suffered the same or worse fate, too.
> I therefore want to define a substantial ground plane, say at a network hub,
> which all network lines, AC mains, phone and other I/O pass over and get clamped
> to (electrically).
> AC mains are easy - MOVs and some X/Y filter caps (maybe I'll add some common
> mode and series mode chokes too, and maybe even a brownout relay to drop it all
> out if the AC volts sag too much. And of course I'll make it safe for humans
> Phone protection I assume is gas arrestors in parallel with TVSs; but what
> ratings are reasonable? and do I need resistors, fuses or PTCs between them?
> Network is harder - at 100Mb/s I don't feel I can put anything much across
> without affecting the signal. Maybe shottky diodes clamping to a grunty +/-
> Cable is harder still - I can't imagine any way to protect it, but I am content
> to lose the cable modem if another strike occurs, as long as I can reduce the
> probability of losing other equipment - and of course I know there's nothing I
> can do about a direct hit (c'est la vie).
> All suggestions would be welcome.
> PS sorry for the cross post, but the subject seemd relevant to all 3 groups.
Just about every computer / electronics store sell surge suppressors.
Many have RJ11 and RJ45 surge-arrests as well. Fairly inexpensive too.
I'm also pretty sure that a coax surge-arrest an be found if you take
the time to look around.