When I was in Phoenix AZ, I had an HVAC go out, I was running an MSL-100, and the tempature got up to 119 degrees in the switch room. This switch was supposedly smart enough to start shutting down cabinets to adjust for the heat. It ran that way for 12 hours, and I had no problems with any parts of the switch itself. The office computers were a different story, along with the T1 equipment racks.