Just reading an article about the analysis of the Fisher Plaza data center fire. Here are some of my thoughts on the issue and prevention techniques.
First of all, the analysis. Most bus ducts don’t have much in the way of “insulation” in them, the copper bus bars are supported at intervals by ceramic supports that space them away from the metal housing and are heat resistant in case of overloads. Definitely, there is plenty of evidence of a major electrical arc, bad enough to melt the copper itself. I would suspect that this was a loose connection.
I’ve seen overload failures of this sort occur in various environments. In one customer installation, an ancient breaker failed to trip and passed a short directly to a 600A 240V entrance. The result was a destroyed bus bar, destroyed panel, and some very traumatized data center equipment.
So, how can we prevent this kind of occurrence from disrupting our data centers? First, retire or avoid very old power equipment. Circuit breakers have a increased chance of failure with age (they may actually get locked on and fail to trip as in my example, causing catastrophic destruction). Also, some older power equipment that is still in common service is known to be unsafe due to poor design or manufacturing issues. Resist the urge to reuse older equipment in other locations.
Second, inspect all electrical equipment at least once a year. Check for hot spots with an infrared thermometer (hot spots may indicate loose connections or failing or overloaded conductors).
Third, make sure there are plenty of fire breaks between pieces of equipment so that a fire that starts at one point won’t damage other things. This is neglected a lot in transformer failures where burning oil can follow cable ducts and cause widespread damage.
Make sure you don’t end up toasting marshmallows in your data center!
Vern, SwiftWater Telecom