MCC Daily Tribune
The Value of Preventative Maintenance
Last summer during a break period, we turned the campus power off to do preventative maintenance on the electrical switch gear located to the north of campus. Preventative maintenance involves cleaning all the components with alcohol to remove dust, bugs, and spider webs. Then the moving parts are lubricated and contacts are cleaned. This is done every five years to insure reliable service from the electric grid.
During last summer's maintenance, four insulators were observed to have cracks in them which could potentially allow electric leakage to ground. Electric leakage to ground on 4,160 and 34,000 volt feeds is a serious problem and potentially catastrophic. In light of these findings, four insulators were immediately ordered and the next shut down was scheduled for December of 2019 to replace them. During this shutdown, all the insulators were inspected again and eight more were found to be cracked. Once again another shutdown was scheduled for July 3, 2020 to replace all 27 of the insulators. Instead of porcelain insulators, the decision was made to replace them with a composite material that is more durable to shock and movement. 27 insulators arrived and they were installed during the July 3rd shutdown. When the 27 insulators were removed, 24 were found to be cracked and degrading.
Had the insulators failed completely, which they were very close to, it would have allowed 4,160 volt bus bars to fall into the cabinet below and short out our entire campus electric system. "Preventative maintenance" found this problem in time.
Our thanks go to the O'Connell Electric crews and our own Mark Lagana, who oversaw the work over the July holiday.
Attached is a picture of a sample of the damaged insulators. There are typically four vertical cracks wherever there was one. Horizontal cracks like the one on the left are the most serious.