How to Wire a Simple 120v Electrical Circuit (with Pictures) Oct 26, 2018How to Wire a Simple 120v Electrical Circuit. Hiring an electrician is usually the best way to go where 120 volt circuits are concerned, but if you are up to it, you might save money by doing some basic electrical work yourself. Normally, for AC, the smooth wire is for the hot and the grooved wire is for wiring to neutral power. Thanks! Yes73%(51)Views: 450K 120V AC Wiring - Roadtreker 120V AC Wiring The other part of this project is wiring up the inverter⁄charger into the 120 volt side of things. The Xantrex manual recommends using 10 gage wire for this, since the maximum current capability of the inverter is 30 amps.