Commercial buildings require more power and have a 347/600V electrical system. The Electricans working with these voltages need to be trained and competent in knowing how to work safely with three phase electrical systems, transformers, switch gears, lighting and more. Residential electricians work on simpler 120/240V single phase electrical systems in homes, but can still handle significant loads that draw a large amount of amperage. Both are essential for ensuring the safety of the property, and people that reside in it.