Floating ground

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Most electric circuits have ground that is electrically connected to the Earth, hence called "ground". The soil is said floating when this connection does not exist.

The conductor is also described as having floating voltage if they are not connected electrically to other non-floating conductors. Without such a connection, the voltage and current flow are induced by the electromagnetic field or the accumulation of charge in the conductor rather than due to the usual external potential difference of the power source.

Video Floating ground

Apps

Electrical equipment can be designed with floating ground for one of several reasons. One of them is security. For example, a low voltage DC power supply, such as a mobile phone charger connected to electricity through one type or another transformer, and no direct electrical connection between the current return path on the low voltage and physical (earth) side. Ensuring that no electrical connection between the mains voltage and the low voltage plug makes it easier to ensure the safety of the supply. It also allows the charger to only connect safely to live and neutral, allowing a two-pronged plug in the countries where this is relevant. Indeed, a home appliance with a two-pronged plug must have a floating ground.

Another application is an electronic test tool. Suppose you want to measure a potential difference of 0.5V between two cables that are both close to 100V above ground Earth. If your measuring device has to be connected to Earth, some of its electronic components must face 100V potential difference across all terminals. If all devices are floating, the electronics will only see a difference of 0.5V, allowing finer components to be used that can make more precise measurements. Such devices are often battery-powered.

Thirdly, floating soils can help remove the ground loop, which reduces noise coupled to the system. Examples of such configuration are shown in the picture on the right. Systems isolated in this way can and do deviations in potential and if the transformer is able to supply a lot of power, they can be dangerous. This is very likely to happen if the floated system is close to a high voltage power line. To reduce the danger of electric shock, the instrument chassis is usually connected separately to Earth soil.

Maps Floating ground

Security

Floating can be hazardous if caused by the failure of the proper ground equipment designed to require grounding, because the chassis can be at a very different potential from nearby organisms, which then gets an electric shock when touching it. Direct chassis TVs, where the set point is lowered by straightening direct electricity, were common until the 1990s.

Exposed residences are dangerous. They live, and can shock the end user if touched. Headphone sockets installed by end users for direct TV chassis are very dangerous, because not only are often live, but any electric shock will pass through the user's head. Sets that have direct headphone and chassis sockets using an audio isolation transformer to make the settings secure.

Floating grounds can cause problems with audio equipment using RCA connectors (also called phono connectors). With these common connectors, signal pins are connected before the ground, and 2 pieces of equipment can have a larger difference between their bases than is needed to saturate the audio input. As a result, plugging or unplugging when power is turned on can produce a very loud sound in the speakers. If the difference in ground tension is small, it tends to only cause buzz and click.

Residual current devices may be incorporated into the system to reduce but not eliminate the risk caused by floating soils.