In smart grid, standardized control networks are typical safety critical components which are under the environments with strong noise and interferences. This paper focuses on the safety mechanisms of standardized control networks in smart grid. The underlying safety mechanisms of standardized wired control networks are analyzed deeply. More importantly, there are very few works considering the safety extensions for wireless control networks. To address this, we propose a combined cyclic redundancy check (CRC) based safety extension mechanism. In addition, key points and open issues of safety-related mechanisms are discussed. To evaluate the safety of the proposed combined CRC mechanism for wireless control networks, error correction capability simulation is performed, which validates the effectiveness of the proposed scheme under the typical noisy background in smart grid. The result supports the usefulness and feasibility of our scheme. To the best of our knowledge, this work is the first to focus deeply on the safety mechanisms for standardized control network in smart grid, especially for the safety extension scheme for wireless control networks.