smkettner wrote:
There is no ground loop because the neutral-ground bond is in just one place, the inverter. No other neutral-ground bond should exist. Any bond at an onboard generator would be broken with the transfer switch same as the inverter when not in use.
Ground loops don't only (or even usually) occur due to multiple GN bonds. That is one type of loop that can occur, but a classic ground loop is entirely within the ground conductor and doesn't involve the neutral connector.
The classic loops occurs when the ground conductor paths form a loop, e.g., in this case because there is a path from the inverter through AC ground into the RV into the chassic, and also from the inverter directly into the chassis. It's not clear if this loop is actually problematic, however.
The ground is for internal failure on either the 120v or 12v side. Needs to be direct to the frame so that no matter what fuses or switches you have on either side the inverter chassis remains connected to the frame in all conditions. This makes the inverter chassis just a safe as touching the frame.
Yes, I understand how grounding works in general, but I'm trying to understand this particular case and the manual recommendations.
In particular, 120v failures are already protected since the chassis is
already connected to ground via the AC grounding wire! So the inverter chassis gets the same grounding protection as all the other 120v appliances in the RV.
For 12V failures, I don't see how an 8 AWG cable is going to help, when the inverter is itself connected with 1/0 AWG cables, so 8 AWG is going to be woefully inadequate. Furthermore, if the goal is to protect against DC shorts, it would make much more sense to connect the cable back to the battery negative terminal, since that's a much more reliable connection than trying to push dead short current through the vehicle body.
Ungrounded electrical equipment leaves open the possibility that YOU become the ground.
As I mentioned above, the unit is already grounded, via the AC ground wire.
Go down to Home Depot and get some #8 green wire and make the connection.
I've already done it (yes, at HD even) - but I want to understand exactly the reasoning behind it. It's not magic - the reasoning behind grounding rules, for e.g. in house wiring, is open for scrutiny and makes a lot of sense. I'm looking for something similar for this grounding terminal.
