RE: POE switches and lightning

[Mark Mayfield <mark.mayfield () metro-inet us>]

About a month ago, we had a lightning strike near our main campus.  We lost one POE Cisco 3560 completely (apparently 
blown power supply), and in a separate but nearby building, another 3560 lost the ability to deliver POE, but continued 
to operate as a switch.  Both had to be replaced. Both were on wiring closet type UPS'es with surge suppression, and 
those were unaffected.

Mark

-----Original Message-----
From: Caleb Tennis [mailto:caleb.tennis () gmail com]
Sent: Thursday, May 13, 2010 10:37 AM
To: North American Network Operators Group
Subject: POE switches and lightning

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.

What's interesting is that various POE switches throughout the entire building seemed to be affected in that some of 
their ports they just shut down/off.  Rebooting these switches brought everything back to life.  It didn't impact 
anything non-POE, and even then, only impacted some devices.  But it was spread across the whole building, across 
multiple switches.

I was just curious if anyone had seen anything similar to this before?  Our incoming electrical power has surge 
suppression, and the power to the switches is all through double conversion UPS, so I'm not quite sure why any of them 
would have been impacted at all.  I'm guessing that the strike had some impact on the electrical ground, but I don't 
know what we can do to prevent future strikes from causing the same issues.  Thoughts?



Confidentiality Statement: The documents accompanying this transmission contain confidential information that is 
legally privileged.  This information is intended only for the use of the individuals or entities listed above.  If you 
are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or action taken in 
reliance on the contents of these documents is strictly prohibited.  If you have received this information in error, 
please notify the sender immediately and arrange for the return or destruction of these documents.