Arc Welding Equipment. Arc Welding Arc welding Arc welding –uses electricity to heat and melt the metal. Shielded metal arc welding Shielded metal arc. - ppt download: Electricity and Welding Must have a basic understanding of electricity to understand welding Must have a basic understanding of electricity to understand welding Electricity is the flow of tiny particles called electrons through a conductor. Electricity is the flow of tiny particles called electrons through a conductor. –Electrons are negatively charged particles. –A conductor allows the flow of electrons. Voltage is a measure of electrical pressure. Voltage is a measure of electrical pressure.