Network isolator

Network isolators are installed as part of a copper Ethernet system, as galvanic isolators.

Network data continues to be transmitted across an electrically non-conducting barrier, through the applied principle of electromagnetic induction, whereby high frequency AC voltages conveying data are induced across an isolating gap.

The network isolator is therefore a passive device, and functions without any requirement of an external power supply.

Network isolators are used in the medical industry to protect patients against leakage currents.

Network connections between medical devices and Ethernet networks (and other non-medical devices, such as personal computers) must be in accordance with the IEC standard IEC 60601-1 (3rd edition). This standard specifically deals with medical electronic and electrical equipment and systems, and classifies non-medical devices as potential hazard sources. A specific hazard stems from possible differences in ground potentials between network components, which when not properly isolated can result in a leakage current that can flow through the patient, which is dangerous, and potentially lethal. Such voltage differences can also arise through incorrect installation and wiring of network systems, electrical shorting within damaged cables and cabling, or shorting between damaged network cables and other voltage sources.

Network isolators work to remove this hazard, by electrically disconnecting medical devices from a network. Isolators may be used as network accessories, built into medical devices, or installed within a medical network system. Networks isolators should be installed as close as possible to the medical device in question.

As they serve no therapeutic or diagnostic purpose, network isolators themselves are not classed as medical electronic equipment according to the standard IEC 60601-1, nor do they fall within the scope of the Medical Devices Directive 93/42/EEC.

...
Wikipedia