7/28/17: Sizing Branch Circuit Conductors

Poll created by dvigstol Employee on Jul 28, 2017

The owners of an office building have decided to install six, Level 2 fixed electric vehicle charging stations (EVSE) due to an increase in workers that drive electric vehicles. Each station has two charging cords and draws a maximum input current of 24 amperes when both cords are being used at the same time. The voltage range of each station is 208-240V, single phase. Since the office building only has 480Y/277-Volt and 208Y/120-Volt systems, the charging station branch circuits will consist of 2 ungrounded conductors with a voltage of 208V between them. Also, due to the location of these stations, the raceway containing the branch circuits will need to be directionally bored under the parking lot and therefore, all circuits will occupy the same underground PVC conduit from the building to a junction box in the ground near the charging stations. What is the minimum size ungrounded, copper conductor using THHW insulation that is permitted by the NEC® for the circuit conductors run to the junction box? Assume that volt drop is not an issue and that all terminations are rated for 75°C.

12 total votes
  • 10 AWG
  • 8 AWG
    Your vote
  • 6 AWG
  • 4 AWG