Surge Protection on Ethernet
https://www.bourns.com/pdfs/bourns_ethernet_poe_article.pdf
http://www.akrossilicon.com/home/component/jdownloads/finish/3-whitepapers/29-ethernet-esd-compliance-w-as1602-wp12-rev1-3-pdf
PCB Spark Gaps
http://www.youtube.com/watch?v=vfP_65gSSBU
Breakdown voltage = (3000 * air_pressure_atm * distance_mm) + 1350
0.1mm = 1650V
0.2mm = 1950V
