Type B ground-fault protection on adjustable frequency drives

This paper describes the IEC type A (AC only) ground-fault detection circuit and its limitations in accurately detecting electrical ground-fault currents in today's modern electrical installations. Discussed are the effects of waveform modifying power sources and the effect of the DC component on the efficacy of type A safety devices. Limitations of UL1053 standard for ground-fault sensing and relaying equipment are discussed. The paper will lead to recommending and applying IEC type B (AC/DC) detection technology for solving these shortcomings.