When is an ELCI or RCD required to be installed?

An Equipment Leakage Circuit Interrupter (ELCI) or Residual Current Device (RCD) is mandated in specific scenarios to enhance safety by preventing electrical shock due to ground faults. The requirement for installing an ELCI or RCD is crucial in environments where there is a risk of leakage current that could result in electric shock.

The correct answer highlights that an ELCI or RCD must always be installed, with the exception being when an isolation transformer is present. Isolation transformers serve as a protective measure by electrically isolating the power supply from the vessel’s electrical systems, thereby preventing leakage currents from reaching the personnel and equipment. In situations where no isolation transformer is used, having an ELCI or RCD provides an essential layer of safety, cutting off electrical supply if a ground fault is detected.

This approach is consistent with safety standards aimed at protecting individuals and equipment. By making the installation of ELCI or RCD a general requirement, it ensures a higher standard of safety across various marine electrical installations, regardless of the specific type of connection or equipment used, thus mitigating the risks associated with electric shock in potentially hazardous environments.