Uninsulated exposed parts, such as electrical conductors, buses, terminals, or components, shall operate at not more than ___ volts in wet locations in Class III, Divisions 1 and 2 locations.

• A. 15
• B. 50
• C. 30
• D. 120

Answer: (A)

In Class III locations, where easily ignitable fibers or materials can be present, the risk of ignition from electrical faults is heightened, especially in wet conditions. Limiting uninsulated exposed parts to a very low voltage reduces the energy that could be delivered if a fault or touch occurs, and also lowers the chance of an arcing spark in a damp environment. That’s why the rule sets a maximum of 15 volts for uninsulated exposed parts in wet locations across Class III, Division 1 and Division 2. If higher voltages were required, you’d need complete insulation or enclosure of exposed parts or choose equipment rated for those conditions to prevent exposure.