If electronic loads have been failing frequently, you can probably find the root cause at the distribution panel(s) supplying those loads.

First, trace the problems to their common point of supply — the last (electrically closest to the load) panel common to the affected equipment. You should look for:

  • Power issues: Voltage, current, and harmonics.
  • Physical issues: Connection integrity and bonding conformance.
Check the bonding against NEC Art. 250, Part V requirements after reviewing the definitions of grounding and bonding in Art. 100. Don’t “retorque” connections, as this actually degrades connections. Instead, use a thermal imaging camera to look for hot spots. Don’t tighten the connection and call that a repair. Ask yourself why that connection is loose in the first place. Probably, the fasteners do not clamp properly and thus need replacement.

In our next issue, we'll focus on power issues.