Measuring current accurately is difficult job in today's industrial plants and commercial buildings.An increasing number of personal computers, adjustable speed motor drivers, and other types of electronic equipment in short pulses and are reffered to as non-linear loads. Non-linear loads draw high peak current, causing harmonics in the load current. This may result in unexplained circuit breaker tripping, or dangerous overheating of neutral conductors and transformers. Currents containing harmonics can only be accurately measured with a true rms or clamp meter.