EV charging equipment in the event of certain faults relies on automatic supply disconnection to protect the user and other members of the public. To reduce the ?chances of receiving a fatal shock, RCDs must operate before the residual current reaches a dangerous level and within the defined disconnection time. Understanding the basic operating principles of RCD’s helps with regard to the specification of the correct type of RCD, based on the characteristics of the EV charger connected to the charge point
The regulations place the responsibility on the specifier / designer to verify the dc residual current content when selecting RCDs, and EVCPs may contain as a minimum requirement Type A RCD’s – Reg. 722.531.2.101, provided it can be determined that the smooth dc residual current does not exceed 6mA. Some charger will not work with Type A RCDs.