How to protect against lightning?
What can we use to better avoid complications from lightning strikes? All our equipment is on UPS and surge protection, but the lightning strike this morning that made the power go off and back on over a couple of seconds seems to have fried one of our routers and one of our switches. I thought having the router and the switch on UPS and surge protection would protect them, but that clearly wasn't enough. What else can we use or install to guard against large spikes like that? Both the router and the switch were on two different APC UPS units in different areas of the office. There were also devices on those UPS's, but only the router and the switch fried. The other devices are fine.
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After an overvoltage incident surge protectors should be either tested or replaced. MOVs can be (to some extent) self-healing for a few episodes but then they burn out and fail open. Unless the surge protectors are provided with monitoring the MOVs can be quite dead and nobody would know without opening the unit and examining the MOVs.
https://iaeimagazine.org/magazine/2004/march2004/metal-oxide-varistor-degradation/
As noci says, keeping the AC line voltage down is not necessarily a complete solution. The magnetic pulse from a near miss can send transients of thousands of volts down signal lines, frying the transceivers at each end. This is less of a problem if the cables are in EMT or shielded trays.
At higher frequencies such as 10Base100 and higher, surge protectors on Ethernet lines can be counter-productive because the MOVs act like a small-value capacitor -- which shorts the signals. Gas tube arrestors may not be useful on network lines because of the high flashover voltage (90V for neon) required to fire them.
Best policy, I/M/O, is to keep two spares of everything on hand at all times.
https://iaeimagazine.org/magazine/2004/march2004/metal-oxide-varistor-degradation/
As noci says, keeping the AC line voltage down is not necessarily a complete solution. The magnetic pulse from a near miss can send transients of thousands of volts down signal lines, frying the transceivers at each end. This is less of a problem if the cables are in EMT or shielded trays.
At higher frequencies such as 10Base100 and higher, surge protectors on Ethernet lines can be counter-productive because the MOVs act like a small-value capacitor -- which shorts the signals. Gas tube arrestors may not be useful on network lines because of the high flashover voltage (90V for neon) required to fire them.
Best policy, I/M/O, is to keep two spares of everything on hand at all times.
Were the signal cables ALSO surge protected?...
If lightning strikes real close any cable can be the pickup. So you may actually need surge protection on internal cables. (or use glassfibre).
So a grounded wireframe around the building can help. ("faraday;s cage").