Due to a scheduling conflict, your plant hired an electrical testing firm other than the one that normally handles maintenance testing during your annual holiday shutdown. The new firm’s test results showed many more problems. For example, the number of defective cables to be replaced was three times higher than in the previous year, and the repairs would be more expensive as well. For example, this firm identified more than a dozen 480V circuit breakers that needed to be rebuilt or replaced.
The plant manager suspects the new firm isn’t as good as the old one. “After all, they took five days instead of four to perform the testing.” How can you sort this out?
The fact the new firm took longer probably indicates higher competence, not less (they aren’t taking shortcuts). You need to ask questions, such as:
- Was the old firm certified by a testing industry association?
- What was the difference in methodology between the two groups?
- What industry standards did each firm apply?
- How does one firm define a defect versus the other?
Perhaps power events severely damaged equipment and the new firm caught those defects. Dig into any power monitoring logs. Look at the test results and discuss failure modes with the new testing firm. Also look at the distribution of results. For example, cables that are not defective will still show normal deterioration.