Symbols.
Earth Ground
Chassis Ground
Subsection 4.2.2 Ground
Ground in electricity has several meanings depending on the context in which it’s used. Ground primarily means the earth when ashore, or the hull aboard ship.
Circuits are grounded by connecting them to ground. This ground connection provides an alternate path for electrical currents to flow back to the source. Ashore, electrical circuits are grounded by connecting them electrically to a rod or pipe driven into the earth, while aboard ship, a connection the hull serves the same purpose. A chassis ground, refers to the point on the metal frame or outer casing (chassis) of an electrical or electronic device where the circuit is grounded. The chassis itself is grounded to the earth or the hull. Ground also refers to a reference point used for voltage measurements. Finally a ground or ground fault can refer to an accidental connection between the circuit and ground
The ground connection serves several important functions:
- Reference Point Voltage is always measured relative to a reference point. By defining a specific point as "ground," voltages at other points in the circuit are measured with respect to this reference.
- Safety Grounding is crucial for safety in electrical systems. In case of a fault or short circuit, excess current can flow to the ground, allowing circuit protection devices like fuses and circuit breakers to quickly interrupt the current flow. This helps prevent electrical fires, shocks, and damage to equipment.
- Human Safety In the event of a fault that causes a live conductor to come into contact with a conductive surface (like a metal enclosure), the ground connection provides an alternate path for current to flow around, rather than through the victim, reducing the severity of electric shock.
- Shielding In electronic devices and systems, grounding is used for shielding against electromagnetic interference (EMI) and radio frequency interference (RFI). Metal enclosures and components can be connected to the ground to create a shield that prevents external electromagnetic signals from interfering with the device’s operation.
