How hot is it? A survey of temperatures inside medium-voltage electrical enclosure across North America

While circuit owners often monitor cable and transformer temperatures on their critical circuits, the temperatures that exist inside distribution-voltage electrical enclosures have not been well documented. This paper studies the temperatures recorded inside electrical enclosures throughout North America. The results were collected over the course of a year at four geographically different locations in cryic, mesic, thermic and hyperthermic soils and from systems operating with phase to phase voltages of 15 through 35kV. This paper illustrates the effects that the ambient conditions, seasonal load fluctuation and installation factors have on the temperatures measured inside enclosures. The internal temperatures impact the safety and long-term durability of the ancillary equipment often contained within distribution-class electrical enclosures such as cable rejuvenation equipment, rejuvenation fluid, smart sensors, partial-discharges sensors, fault indicators, etc. and this data should be given consideration in the standards and installation guidelines for those devices.