This document proposes improving the SEP routing protocol in wireless sensor networks by combining it with the Insensitive Fuzzy C-Means clustering algorithm. The SEP protocol is an existing heterogeneous routing protocol that increases network stability but has limitations. The proposed SEP-εFCM protocol selects cluster heads using εFCM clustering, which can create more balanced clusters and reduce energy consumption. Simulation results showed the SEP-εFCM protocol performed better than the original SEP protocol, with more remaining live nodes and energy over time.