Comments and answers to some issues discussed earlier in this thread:
The 3-phase, 4-wire delta circuit has 240 volts between phases with 120 volts between two of the phases and the grounded neutral and 208 volts between the high-leg phase and neutral. In general, that connection was used for industrial installations to provide 3-phase, 240-volt power for motor loads with a limited amount of 120-volt power from two of the phases and neutral for receptacles and lighting. The high leg was never used with neutral (only with the other phases). The 3-phase 208Y/120-volt wye connection is used to allow all three phases to supply 120-volt loads from line to neutral and 3-phase loads line to line. 208 volts is low, but within tolerance for 230-volt, 3-phase motors. If a NEMA 14-50 receptacle is connected to a 4-wire delta circuit, its line terminals must be connected to the two phases which are 120 volts to neutral (not to the high leg). The line terminals of a 14-50 receptacle may be connected to any two phases of a 208Y/120-volt circuit.
I just made some measurements on the Nissan EVSE that came with my 2019 SL Plus. The neutral terminal of the 14-50 plug is not connected to anything in the EVSE. The 120-volt adapter connects line, neutral, and ground from the 120-volt plug to line 1, line 2, and ground of the 14-50 plug. Line and neutral of the 120-volt are connected to line 1 and line 2 of the 14-50 plug respectively when inserted one way or line 2 and line 1 respectively when inserted the other way. This allows the EVSE cord to go either up or down from a 120-volt wall receptacle, depending upon how the 14-50 plug is connected to the adapter. THE NISSAN 120-VOLT ADAPTER SHOULD NOT BE USED WITH ANY OTHER EVSE.
The Nissan EVSE will work on 240-volt circuits and 120-volt circuits with its adapter, but will not work on 208 volts. It will start to charge and then shut down after a few seconds because the voltage under load is lower than it deems acceptable. AeroVironment (no longer available), Clipper Creek, Grizzl-e, and other manufacturers make EVSE's that work fine on both 208- and 240-volt circuits.
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL Plus purchased 8/10/2019