A generator uses fuel (petrol or diesel) to turn an alternator that generates electricity for a range of on-site purposes. Standard power outlets allow users to plug in their power tools and lights in construction environments that don’t yet have permanent electricity supplies. The higher the wattage, the higher the output — and you’ll need high outputs for large power tools such as SDS max hammer drills and extraction units. The handy features to look out for include dual voltage output, impact-resistant casing and a waveform, maintenance-free alternator.