When alternating current (AC) prevailed over direct current (DC) in the late 1800s, one of the deciding factors was the need for voltage levels to be raised and lowered throughout the power system to ...

Note: This article is based on the 2020 NEC. A transformer transfers electrical energy (power) from one system to another by induction, with no physical connection between the two systems (other than ...

In the original version of this article, the second figure contained an error. The image has been updated. It’s important for engineers to have a good, working ...