Grounding and power sources

[Super God]

Hello,

I had a question relating to my s1r replication I have going on.  I was going to do a few tests, but first I wanted to see if someone had the answer up front.  I had three different power supplies in mind for my tests, one 110 inverter, a capacitor bank, and a high voltage power supply.  Now, the plug threads into the engine block and is grounded through the same, but will the 110, capacitor bank, or hv power supply ground through that too?  The battery is connected to the ground of the car, I didn't want an explosion or something on my hands.  I noted in some early experiments that a dc wall wart will not ground through the ac ground (green wire) but instead only ground to the other end of the supply.  I am hoping this is the case with the inverter and the other supplies.  I didn't want to have to have the risk of touching the metal body of the car that is charged with one wire of a capacitor bank or inverter or something.  I'm just thinking safety here for me and others around my car.  So, my question is, will any of these supplies inadvertently ground to the negative of the battery/car?

Thank you!  If there is anything you are confused about in my question let me know, I might have worded it weird or something.

-Brian