On Jun 15, 2009, at 10:24 AM, Tom Penney wrote: > One of our 4 machines lost a drive during the incident. Lots of admin > were there when I arrived having other hardware issues. this is the > second time in 4 years that power has gone out to our rack. Aside from > that, visi has been great, but this is not good. does anyone colo at > IP house? Yes, and they had a similar power outage a year ago this past March. We didn't lose any drives during that outage, but half their entire data center was without power. This was one of the notices sent by Bil MacLeslie (ipHouse CEO): ... This morning at approximately 8:51am a 480v circuit breaker tripped, shutting down power to an integrated 480v/208v transformer & PDU (power distribution unit). This caused a power outage for some of our colocation customers who are fed power from this PDU. At 9:32am, power was restored to the PDU and by 9:56am all circuits were back on. I personally staggered powering circuits back on to watch for an overload condition. The NEC (National Electric Code) requires that the maximum circuit load be 80% of the rated capacity of the circuit breaker, e.g. 16A maximum on a 20A breaker. We regularly take power readings from each circuit and maintain power utilization within the requirements of the NEC. When reading power utilization today, we found nothing that would cause the 480v circuit to be overloaded. All indicators show that the circuit is not overloaded, nor is the PDU overloaded. The true cause for the breaker being tripped will likely never be known, but does not appear to be from overloading. Because of this outage, some customers have had equipment failures that are indicative of a voltage surge on the system. The UPS and PDU system is protected by a transient voltage surge suppressor (TVSS) and we are investigating the aspect of a surge further. We are also currently investigating to see if the UPS contains data that may shed some light on the situation. As we get more data, we will provide it to you. ... --- Eric Crist