POE switches and lightning

Fri May 14 23:42:45 UTC 2010

>> We had a lightning strike nearby yesterday that looks to have come inside 
>> our facility via a feeder circuit that goes outdoors underground to our 
>> facility's gate.

Perhaps there was a "move" of the earth-level relative to the neutral 
line.
I have no idea how neutral-line to earth potential is handled in us, but 
here in austria we use a so called "nullung".
That means that the earth-ground potential line of the building (which 
includes also the lightning conductor) is connected to the neutral power 
line where it enters the building, keeping this potential-difference low.

Theres also a potential between earth ground and the neutral-phase of the 
online-ups.

The ethernet-cables; utp or stp?
pannels correctly earthed?

Perhaps a electrician should check the earthing.

Also all copper lines that enter the building should be protected by 
lightning protectors.

Kind regards,
 	Ingo Flaschberger