Electrocoating lines run DC current through hundreds of litres of liquid to deposit paint onto vehicle bodies and components. The process is standard across automotive manufacturing. The hazard is equally standard: anyone near an energized tank is one slip away from electrocution, and nothing about the tank's appearance distinguishes energized from safe.

The conventional controls are procedural — signage, permits, training, and the assumption that nobody approaches the tank while the rectifier is on. Procedures are necessary. But a procedure cannot see a person, and it cannot cut power. On a line that runs every shift, the question is not whether someone will one day approach an energized tank. It is what happens in the seconds after they do.

Interlocking power to presence

The engineering answer is to make human presence and rectifier power mutually exclusive — automatically, at every approach path, on every shift. Stated as a specification:

  • Monitor every approach to the tank area, with no blind path left uncovered.
  • Cut rectifier power within a second of a person entering the protected zone.
  • Keep power off until every monitored zone confirms clear, then restore automatically — no production babysitting.
  • On any system fault, land the rectifier in the off state.
  • Log every cut, clear, and authorized override with a timestamp.

Two details in that list carry most of the safety value. Automatic restoration means the system does not depend on a supervisor to reset it, so there is no operational pressure to bypass it. And the fault behavior means a failed sensor turns the rectifier off — the failure mode itself is safe.

Proven on a live line

Bath Guardian implements exactly this interlock. It is deployed on a live e-coat line at a global automotive components conglomerate — monitoring every approved entry point to the tank area and removing rectifier power when a person enters the protected zone, on every shift. The system watches approaches a human supervisor physically cannot watch simultaneously, and it never looks away.

For EHS leaders, the audit trail changes the conversation as much as the interlock does. Every power cut is a recorded event: when, where, how often. That record turns an invisible hazard into a measurable one — and measurable hazards get engineering budgets.

If your plant runs electrocoating or electroplating, the assessment starts with a walk of the tank line: entry points, approach paths, and what currently stands between a person and an energized tank. We do that walk with you.