Floating ground

Without such a connection, voltages and current flows are induced by electromagnetic fields or charge accumulation within the conductor rather than being due to the usual external potential difference of a power source.

Ensuring that there is no electrical connection between mains voltage and the low-voltage plug makes it much easier to guarantee the safety of the supply.

Other applications include aircraft and spacecraft, where a direct connection to Earth ground is physically impossible when in flight.

[4] To reduce the danger of electric shocks, the chassis of the instruments are usually connected separately to Earth ground.

Sets with a headphone socket and a live chassis use an audio isolation transformer to make the arrangement safe.

A residual current device can be incorporated into a system to reduce but not eliminate the risks caused by a floating ground.