The paper deals with the design rules included in the RCCE code applicable to electrical, and instrumentation and control systems and components contributing to safety-class functions. It is a major document in the relationships between the Owner and its suppliers and the safety authorities. The code is periodically submitted to the Nuclear Safety Authority Assessment. Initially used for the French PWR program and published by the French Society for Design and Construction rules for Nuclear Island Components (AFCEN), the code evolves to comply with third generation PWR nuclear islands and aims to comply with national regulations if needed in addition to French regulations. It gathers within one set of rules, the design and construction practices of, the electrical and I&C systems and components, and installation engineering documents. Brief presentation of some items is proposed: - Relationships between Safety Analyses Report plant system and installation engineering; - Off-site and on-site sources requirements; - Periodic tests and permanent monitoring requirements to guarantee the safety function availability; - I&C architecture and Human Machine Interfaces; - Digital I&C systems requirements; - Establishing qualification to ambience conditions, that includes normal and mild conditions and, harsh and severe accident conditions. Custom-made approach based on the families of ambience defined as a combination of equipment mission time, and normal and abnormal conditions (pressure, temperature, radiation) enabling to cope better with environmental conditions; - High and Low frequencies disturbances protections (Lightning, GSM, DECT, WiFi); - Project data used by any supplier or designer such as site data, temperature of rooms, maximum design temperature of equipment, the voltages and frequency variation range and tolerances of the alternative current and direct current electrical networks, the decoupling data of environmental conditions; - Electrical equipment separation requirements and isolation and decoupling solutions designs; - Electrical enclosures design requirements. A conclusion on the evolution of AFCEN organization in charge of comprehensive set of technical codes on the design, construction and surveillance of civil work structures, fire protection, mechanical structures, the core and fuel design, the electrical and I&C equipment and systems of PWR nuclear island.