Good infographic on data center downtime. What should strike you right away is the most common cause of outages is power. Also of note is that of the 7 causes, only 1 was IT equipment failure (e.g. networks, servers). This aligns to what I’ve seen with Oil & Gas field networks. The best two techniques for managing power issues is to add network redundancy and ensure qualified electrical engineers correctly design the network power sources.
http://www.emersonnetworkpower.com/en-US/Brands/Liebert/Infographics/Pages/Causes_of_Downtime.aspx