Welding 101 Practice Test 2026 - Free Welding Practice Questions and Study Guide

Fire classifications guide which extinguisher to use. Type C fires are electrical fires, involving energized electrical equipment such as power tools, outlets, or welding machines. This matters because water or other conductive substances can carry current and cause shocks, so the safe approach is to use a nonconductive extinguishing agent (like dry chemical or CO2) and, if possible, disconnect power before fighting the fire. The other materials listed correspond to different fire classes: ordinary combustibles like wood and paper are Class A, and flammable liquids are Class B. Saying it covers all types isn’t correct because each class needs a different extinguishing method.