Direct from Tesla WC support:

"DIP switch 1 should stay down. The text is a little confusing and it should say relative 240VAC "
Relative between the two terminals, NOT relative to neutral or ground. So whether you have real 240 or 208 VAC, DIP Switch one should be down.

from the TWC manual:
Switch Position 2:
• DIP Switch Position 2 should always be set to UP.

 

If I recall, the instructions speak of two things, voltage and the presence of a neutral. In household wiring, both conductors are "hot" (meaning there is no neutral) and the voltage is nominally 240V across them - it's easy to settle on the "240V or less, no neutral" choice. (An electrical neophyte who doesn't understand they mean "nominal" and "across the conductors" needs an electrician.) But in commercial wiring derived from 3-phase service, a single-phase circuit might include a neutral conductor (as I understand it, as a non-electrician fascinated with the many different possible arrangements - delta, wye, oh my!) The problem is that no choice is provided for "240V or less, with neutral".

I believe the convention is that a conductor (that is, not a ground) is either "hot" or "neutral", the latter being connected to ground somewhere (once), nominally at zero volts (but not to be trusted). If you really have two "hot" conductors, then your electrician made a mistake. If one is a neutral, your electrician was justifiably mystified, and guessed wrong.

One would hope that a Tesla-certified electrician would not have had to guess. You'd also think the Wall Connector would immediately reject an incorrect guess, if it was going to be fussy about it. Life is strange.

 

Think I figured it out. Thanks to those that weighed in. First, talked to Tesla today and they said there was no way I would get a solid green light (and also be able to charge the car 2 or 3 times like I did) if the electrician failed to put the dip switch in the down position . He said the design of the switch would only allow it to be in the up or down position. He basically said there was no plausible explanation for what happened (he mentioned ghosts).

Sooooo, things like this bug me so I went down to the warehouse and pulled the cover off the wall connector (the proper name for what most people including me call a charger (and only after flipping the breaker off). It took all of 5 seconds to place the left dip switch halfway between up and down. I plugged the front of the connector back in, set it in place and flipped the breaker back on. Guess what happened? Video below.

What I'm surmising happened is that the electrician failed to push the dip switch all the way down and, over the last 3 or 4 weeks, vibration or current caused it to pop back to the "Up" position. I almost wanted to leave the dip switch in the middle and see if it would indeed do that but don't want to knowingly abuse electrical equipment.

Rant almost over. First, why does Tesla use such rinky dinky dip switches. I've seen better ones on a 20 year old garage door opener. Why does it even have them in the first place. This makes the 4th different brand of charger I've had and all the others were much more robust inside (no little switches to flip).

Second, why isn't the default setting from the factory set to "240V or less" i.e. the down position. Should even have a piece of paper tape over it saying "Only flip to up if voltage is greater than 240". You're asking every electrician in America to flip that stupid little switch down (my electrician said you should never have over 240V whether it's commercial or residential as long as it's hooked up properly).

I have the contact info of the tech I talked to today. I'll call tomorrow and get his email and forward him a link to this post. Hope this helps if anyone gets flashing red lights on their connector after a seemingly proper install.

Okay, rant over.