A month or two before the annual maintenance shutdown, the plant has a testing firm conduct thermography on the busways and in various panels and cabinets. Then, during the shutdown, any bad connections are fixed.
The plant hired a new plant engineer a few months ago. She calls you into her office and tells you she put all the test data (connections that made it onto the “suspected connection” list during themography) for the past five years in a spreadsheet.
Not only has the list grown each year, but nearly all of the same connections show up year after year. She insists this is not normal, and she wants you to find out what’s going on. Where do you look?
Start by visually inspecting the previously identified “suspect” bus connections. Belleville washers are commonly used for these connections. If you see the cup overhanging the connection, the connection is made incorrectly and the hardware must be replaced.
Then visit the tool crib and ask to see the calibration records for the torquing screwdrivers used to repair bad connections in termination panels. If there are no records, you’ve found another problem.
Find the work orders for the connection repairs done in the last shutdown. Talk with the people who performed the work. If they merely tightened the connections, you can report to the plant engineer that she needs to address a training deficiency.
