Qualifying preamble: I had lost track of what "page 4" was referring to, until i got to the bottom (while writing this ramble) where you helpfully (re)provided the link.
THAT MNDC PANEL IS FOR HOUSE-ROOF-SIZED SYSTEMS.
The grounding connections (etc) shown on page 4 are WITH THAT IN MIND.
It's for such contingencies as lightning strikes, and the fact that HOUSE systems can have much higher voltages (and currents) than you'll be dealing with.
(((i had mistakenly thought that "page 4" was in the Inverter manual)))
Typical RV systems do not have to "ground" the panel negative.
You should read your PANEL's instructions to see what THEY recommend (they may want the panel frame tied to a specific polarity, to deal with wind- and capacitively- induced surface charge on the panels)
The MNDC page 4 also shows a GFCI breaker
on the solar panel feed ... the right-most small (5A) breaker with the little green zig-zag component (a resistor) across it ... it's mechanically coupled to the 63 amp breaker next to it, which would trip out the panel feed to the controller. Your panels wouldn't generate enough current to trip that.
That's merely an example of how far your intended use of the MNDC box differs from the goal of the page 4 diagram.
... the following was written before realizing that the above preamble was needed:
Correct, I'm not connected to the sprinter's electrical system. I have the DC ground connected to the 5/16 stud and the manual says that is sufficient (pg. 4)
Confusion rains and reigns again: when you mean "my DC negative" please say that rather than "ground" (since you are also connecting AC and shore-power green-wire ground).
My inverter is ground to the van chassis though.
See? That ground is the external metal box, and truly means "earth ground" (since it's part of the green-wire connection in your shore power). If you probe the inverter when it's just sitting disconnected on your dining room table, you'd (99.9% certain) discover that that "ground" is totally isolated from the other six terminals (DC+, DC-, AC hot in, AC neutral in, AC hot out, AC neutral out). The "ground" will connect to the 3rd pin on the AC connections.
Would you recommend having two switches then (positive and negative)?
... there's "recommends" and there's "suggests" (along with "hints" and "nudges" and "shouts"). Minnesotans add in "could". "Practicalities" come in from the side to muddy the waters.
(a) I don't necessarily "recommend" disconnecting both sides of the battery, but you certainly could.
Simply disconnecting one side is "enough" from an electronics point of view: you have interrupted the current path battery-wire-load-wire-battery.
(b) if i was trying to disconnect both sides, i'd "recommend" ("practicalities" allowing) a double-pole switch, so you only have to flip ONE handle to achieve the full disconnect. Having two separate switches is an invitation to only flipping one, and discovering (the hard way) that you should've flipped both (or even simply "the other one").
(c) if i was building your system, i'd probably just use one switch in the positive feed, as CalBiker suggested, and as per my last drawing.
AND:
My negative loads are connected to the 5/16 stud too (pg. 4)
Since you ARE thus tying your "house" system to the Sprinter's frame, putting only one switch in the negative may lead to "issues" (mainly since you have other current/voltage sources involved (solar and inverter).
(BUT: (engineering speak here
from purely the battery's point of view disconnecting only the negative DOES take them out of the game... if there's no way for current to reach the battery's negative post(s), the house batteries will NOT be "in-circuit".)
That said, you (for example) haven't shown how the shunt sensor is powered (some shunt assemblies include a small circuit card that has its own private two-thin-wire feed... how is that powered? does it provide a sneaky "back door" to the (theoretically) disconnected battery?. Again: if the ONLY connection on the house battery's post is to the Big Switch, and then the Big Switch is what feeds the shunt, the Big Switch will indeed remove the house batteries from the game.
By having the house negative bar tied to the Sprinter Frame, you *are* still providing possible pathways for the Sprinter's Starter battery to cause confusion (if a (let's say wrench) tool accidentally bridges a vehicle positive to the house system's wiring).
note: here is when i woke up to the need to write the "preamble" (far above).
I want to put wires in the "AC out" side of my inverter.
Yes.
The positive wire will go to a 20amp circuit breaker
AC wires do NOT have a "positive" ... they have a "hot" (or "line") and a "neutral" (or "return").
do not use the word "positive" when referring to AC.
(and it doesn't hurt to say it as "110v AC" to doubly-verify that's what you're talking about)
and then connected to my outlets in series PARALLEL.
...
Are the outlets connected to the battery through the inverter's positive cable to the 250amp, or do I need to connect the wire from the "AC out" to the top nut of the 150amp with the inverter? (pg.6) The reason why I ask is because the bottom nut with the battery is a point for positive DC loads (pg. 5).
Again, you've lost me with the above ... the inverter should be totally isolating your 110 vac outlets and wiring from the DC side of things.
--dick