This system has no AC input.
The distance from the autotransformer which is creating the neutral from the L1 and L2 inputs to the neutral bus appears to be approximately 2 feet.
Certainly much shorter than from the service transformer to the primary panel in a grid derived system.
Thanks, but my question was not from service transformer to mains panel (since neutral from service transformer does not connect-through) but from primary bond after meter to mains panel).
I have L1/N/L2 coming from grid/pole/service transformer over into house and into utility meter, but only L1 and L2 come out of utility meter into my main breaker box containing only a single mains breaker. Ground from a nearby ground tod as well as bonded to water main enters that main breaker box and is bonded to house neutral there, from which L1/N/L2/G pass through ~4” of conduit to my mains panel on the interior side of that exterior wall, where the mains panel is.
Ground and Neutral are on distinct electrically isolated bus bars in my mains breaker panel (meaning the panel with all my home’s breakers but no main service breaker, since that is in the small breaker box on the other side of the wall and connected to the service meter).
So if I understand that earlier post correctly, he saw better-balanced L1 vs L2 voltage by bonding neutral to ground again within the breaker box where the breaker connected to the Autotransformer was located.
I believe there is only supposed to be a single bond between ground and neutral in the system, so unless he is connecting L1/L2 from a 240V inverter to an Autotransformer that goes on to power 110/120V loads, a second bond directly in a mains panel does not make sense.
If we are taking about an isolated ‘Critical Loads’ panel serving 110/120V circuits (in addition to 240V circuits), then of course a new primary bond between ground and neutral within that isolated critical loads panel would be necessary.
But in the case that energy is being served both back to the mains panel (where the primary bond should already be) as well as on to a critical loads panel, I believe neutral can be ‘passed through’ from mains panel to critical loads panel.
We’re talking about a 240V inverter, correct? So no neutral present.
So if you just run L2/N/L2 from the mains panel to the inverter, only connect L1 and L2 to the inverter AC input and pass N on to the Autotransformer along with the inverters L1 and L2 outputs, you should be able to provide full split-phase service to a new critical loads panel in a manner that does not require a new ground-to-neutral bond (and continues to work just fine when the grid goes down).
A new ground-to-neutral bond in a new critical loads panel should work fine as well, but may cause issues with how well load balance of the non-critical-loads portion of the house load performs.
Passing-through neutral from the primary bond around/through the inverter and on to the Autotransformer and Critical Loads panel seems like the safer was to assure there is only one neutral for the entire system (with or without grid active).
And if I’ve misunderstood and this is a true off-grid system, then of course a single proper primary ground-to-neutral bond needs to be created, ideally in the main panel.