IEC 62368-3:2017 applies to equipment intended to supply and receive operating power through communication cables or ports. It covers particular requirements for circuits that are designed to transfer DC power from a power sourcing equipment (PSE) to a powered device (PD).The power transfer uses voltages at ES1 or ES2 or in very specific cases voltage levels at ES3.Any cable provided with a connector defined by an industry standard that permits DC power transfer between equipment is considered a communication cable even if communication does not take place. For example, a USB cable can be used just to recharge a portable device battery.This International Standard is to be used in conjunction with IEC 62368-1:2014.It has the status of a group safety publication in accordance with IEC Guide 104.The subclauses of IEC 62368-1 apply as far as reasonable. Where safety aspects are similar to those of IEC 62368-1, the relevant clause or subclause of IEC 62368-1 is given for reference in a note in the relevant subclause. Where a requirement in IEC 62368-3 refers to a requirement or criterion of IEC 62368-1, a specific reference to IEC 62368-1 is made.This group safety publication is primarily intended to be used as a product safety standard for the products mentioned in the scope, but shall also be used by technical committees in the preparation of standards for products similar to those mentioned in the scope of this standard, in accordance with the principles laid down in IEC Guide 104 and lSO/lEC Guide 51.Keywords: Communication, Safety, Cables, DC Power Transfer,