A device would quickly detect and shut down faulty power lines. Raj Aggarwal and his colleagues at the University of Bath, uk, have developed a detector that picks up uncontrolled jump of electricity to the Earth, originated from a fault. Faults in power lines may result in power cuts and possible explosion at power stations. Aggarwal says the new device reacts to faults by sensing high frequency sound of an electrical arc. It can listen to a noise of 100,000 Hz and switch off the faulty circuit in nearly three milliseconds. When the detector was tested on a transmission line in South Wales, it picked up every fault (New Scientist , Vol 155, No 2098).