Standards Development

Scope

This International Standard applies to switching device for islanding, hereafter referred to as SDFI, for household and similar uses, primarily intended to be used for energy efficiency (EE) purposes with local production and/or storage of energy.SDFI are intended to be installed in low voltage prosumer electrical installations (PEI) able to operate in island mode as defined in IEC 60364-8-82, so called islandable PEI.SDFI are used to disconnect the PEI from the grid to allow operating the PEI in island mode and further reconnect the PEI to the grid.They are intended to be used in islandable PEI which operate:–        in direct feeding mode and island mode (delivering the electrical energy to current-using equipment of the PEI);–        and in reverse feeding mode to the grid (delivering the electrical energy to the grid).SDFI are part of the electrical installation.This document applies to SDFI for operation in AC single or multiphase main circuits with rated voltages not exceeding 440 V AC, frequencies of 50 Hz, 60 Hz or 50/60 Hz. They are intended to be used in installations with prospective short circuit currents not exceeding 25 000 A. DC operations are not covered by this edition and are kept under consideration for a future revision of this document.The SDFI is composed at least of one switching unit (SU) and a control unit (CU) to monitor its switching operations from grid connected to island mode and reverse wise.The SDFI can be provided with a communication interface for exchange with external systems such as the CEM (Customer Energy Manager).NOTE 1 See IEC 63402 series for CEM standard, under development.According to the intended use, the SDFI can be interlocked with the SRCSD or, both can also be integrated in a single unit.NOTE 2 See IEC 63445 for SRCSD standard, under development.NOTE 3 (Under consideration) According to its intended use, the SDFI could also be used as the interface switch. It could also be used or integrate the function of “loss of mains protection” (also called interface protection, see 3.16 and 3.35 and of IEC TS 62786-1:2023). In such cases, additional requirements apply. Requirements for the interface switch and “loss of mains protection” function are not covered by this edition and are kept under consideration for a future revision of this document. Specific requirement according to local installation rules, regulations (e.g. grid codes) can apply for loss of mains protection. Those can also be subject upon agreements with system operators.SDFI are intended for use in circuits where protection against electrical shock and overcurrent is provided according to installation rules for low voltage electrical installations, unless the SDFI already contains such protective function.SDFI are normally installed by instructed persons (IEC 60050-195:2021, 195-04-02) or skilled persons (IEC 60050-195:2021, 195-04-01). They are normally used by ordinary persons (IEC 60005-195:2021, 195-04-03) and does not require maintenance.The requirements of this document apply for standard environmental conditions. They are applicable to SDFI intended for use in an environment with pollution degree 2 and overvoltage categories III according to IEC 60664-1:2020. They have at least a degree of protection IP 20 according to IEC 60529. Additional requirements can be necessary for devices used in locations having more severe environmental conditions.SDFI do not, by their nature, provide an isolation function nor the overcurrent protection. However, isolation and overcurrent protection functions can also be provided as covered by relevant product standards.It is important to note that the main overcurrent protective device of installations cannot be used as SDFI in single dwellings or similar islandable PEI (see Annex D.5 of IEC 6036468-82:2022)