Question 176Electricity & Electronics - 1st Asst/Chief

The correct answer is D) contactors and relays are mounted on non-conducting panels. The reason this is the correct answer is that the use of non-conducting (insulating) panels for mounting contactors and relays in motor controllers helps prevent grounding issues. By isolating these critical electrical components from the conductive metal cabinet or enclosure, the risk of unintended grounds is greatly reduced. This design practice is an important safety measure to ensure the reliable operation of motor controllers in marine and other applications. The other answer choices are not directly relevant to why motor controllers are seldom troubled by grounds. Shock mounts, cabinet heaters, and special wire insulation do not inherently prevent grounding problems in the way that non-conducting panels for electrical components do.