Why are the metal frames of some electrical units grounded?

The grounding of metal frames on electrical units is fundamentally a safety measure, specifically designed to protect against electric shock. When electrical components can become energized due to a fault, grounding provides a direct path for any stray electrical current to flow safely into the ground. This reduces the risk of someone coming into contact with the energized frame and suffering severe injury or fatality as a result of electric shock.

In addition, grounding can help ensure the proper operation of protective devices such as circuit breakers and fuses, which can quickly respond to these faults. By routing excess electricity away from human contact and allowing safety devices to work correctly, grounding is an essential practice in electrical safety standards. This is why grounding metal frames in electrical units is crucial for protecting both personnel and equipment.