Think of an electrolytic cell as a reverse battery (a battery is also called a galvanic cell). Instead of using a chemical reaction to store and release electricity, it uses electricity to create a chemical reaction. In a battery, the anode is negatively charged, and the cathode is positively charged. In an electrolytic cell, the anode is positively charged, and the cathode is negatively charged.
Electrolytic cells have many applications, so if you change specialties enough, you are likely to work with them in one way or another.
The most common use of electrolytic cells is to produce oxygen and hydrogen from water. Water isn’t generally considered an explosion hazard (when superheated, it is) or a fire hazard. But oxygen and hydrogen definitely are both.
Another common use of electrolytic cells is for electroplating. This is a metal finishing process that is often used instead of painting. In this process, one metal is bonded to another. A similar process, which is used to finish items such as the metal panels used to construct kitchen appliances, is enameling. In this process, powdered glass is fused to the metal. But high heat — not electrolysis — is used.
The short (less than a half page) Annex doesn’t attempt to cover all applications. It uses a typical application, and yours may differ. But it’s a good guideline from which to work. The typical situation is an employee who uses manual contact to make adjustments and repairs. That application is such that the exposed energized cell and metal floor present an electrical hazard to the employee.
The Annex then lists seven ways to protect this employee. For example, the employee can wear protective boots or an insulating surface (temporary or permanent) can be provided for the employee to stand on. Those are two personal protective equipment (PPE) solutions. Another solution is to provide a conductive surface for the employee to stand on and then bond it to the cell; this eliminates a dangerous difference of potential.
A small subsection says that power supply circuits and receptacles in the cell area should comply with Sec. 668.21 of the NEC. It then goes on to recommend that receptacles for portable electric equipment not be installed in electrolytic areas and that pneumatic powered portable tools and equipment be used instead.
