[c-nsp] Galvanic isolation for Ethernet?

[Charles Sprickman]

On Aug 19, 2014, at 11:48 AM, Victor Sudakov <vas at mpeks.tomsk.su> wrote:

> Scott Granados wrote:
>> This problem sounds a lot like a dissimilar grounding issue.  Sounds
>> like a potential between buildings is causing problems.  I don?t
>> know if this is feasible but a common ground might solve some of the
>> problems.
>> 
> Our electricians say that everything is correct, that all the
> grounding circuits are interconnected and they measure their
> parameters annually. I lack the necessary qualification to call them
> liars (even if they are lying which I doubt).

It still might be interesting next time you have a failure to put a
voltmeter between the switch chassis ground and each pin on the
ethernet cable that blew the port.  If you see anything measurable
that might at least tell you if its something like a transient
lightning-induced spike or a weird grounding issue (I think).

OT, but long ago I worked at an ISP where we once had a few hundred
phone lines going to modems and the lines ran up the buildings
freight elevator shaft.  Each time someone had a freight elevator
delivery you could hear the sound of a bunch of modem relays
clicking as a bunch of users were disconnected.  This was voltage
induced in the phone cables from whatever power cable the bundle was
lashed to.

Charles

> -- 
> Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
> sip:sudakov at sibptus.tomsk.ru
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