Strange things have been happening in the plant lately. Rumors are circulating about sabotage and industrial spies. Many operators refuse to work at particular machines. Among the many complaints:
- Three different drinking fountains routinely shock people.
- Machines sometimes shut down in mid-run for no apparent reason.
- Red (stopped) and green (running) lights are on simultaneously, though one's dimmer than the other.
These are symptoms of circulating currents and differences of potential. Installing those ground rods is a waste of money and will delay an actual solution. When explaining this to your boss, use these facts:
- Kirchhoff showed that electricity flows through all paths presented to it, dividing flow inversely proportionate to impedance.
- "Ground" means "earth," [NEC Art. 100]. That's a high-impedance path to the source (electricity returns to its source — making a circuit).
- You need a low impedance path.
- Proper connection of the grounding strap on each distribution transformer.
- No L-G bonds on feeder (and branch) panels and circuits.
- Metallic raceway is electrically continuous.
- Panels and equipment housings are bonded per NEC Art. 250, Part V.
