A Study on Residual Current Device Nuisance Tripping Due to Grounding Resistance Value

Protection against leakage current is vital in an electrical system to protect humans and equipment from electric shocks and fire risk. Residual Current Device (RCD) is a protective device used for protection against small leakage current. This device is designed to disconnect the circuit whenever a fault is occurred, by measuring the different value of current between phase and neutral. However, inappropriate tripping also known as nuisance tripping is influenced by the improper grounding system, high frequency from power supplied and presence of harmonics. The aim of this paper is to investigate the residual operating current and operating time of RCD behavior towards the poor grounding resistance value. Besides that, the effect of different type of load were considered in the experiments. The sensitivity of RCD sample used in this research is 30 mA type-AC. RCD operating current and voltage are evaluated and compared with the requirement by international standard The results show grounding system with high resistance value affects the operating time of RCD, thus lead to nuisance tripping.