Grid Tied Inverter with Neutral Loops?

[jgilly69]

HI All! Well getting ready to do the final permanent install for my XW+ in a grid tied inverter with AC coupling. I have been pouring over the documentation for wiring diagrams but the neutrals have been perplexing me? I have including a wiring diagram for reference. The XW+ units are all bonded internally for the neutral connections. So you shouldn't have to run a separate neutral if you DONT have a disconnect the panel connection that includes the pulls the neutral?

My plan is only to feed a critical loads panel with the XW+ and a SMA SB or SolarEdge inverter, and if the condition exists to backup (load) the connected grid feed panel using an interlocked breaker using a Double Throw Double Pole disconnect. The DTDP disconnect will have a bonded neutral to both load and grid so I SHOULD only need to break the pair of HOTS.

Anyone else have this condition and have trips as a result of the neutral loops?

Thanks!

 

[jgilly69]

Funny - I found my answer in another manufactures documentation! What a pain! Still curious what people are doing in the on-grid vs off grid panel connections when connected at the same time?

AC System Bonding Multiple AC Neutral-to-Ground Bonds:
Verify that only one neutral-to-ground bond exists in the system. Having more than one neutral to-ground bond in a system violates local electrical codes, may create a shock or fire hazard, and may cause some sensitive equipment to malfunction.

Failure to follow these instructions can result in death or serious injury and will Void the Warranty.
System bonding refers to connection (bonding) of one of the current-carrying conductors of an electrical system to ground. This creates a "grounded conductor" or "neutral" that is at ground potential but is separate from the equipment ground conductor. System bonding must be done at only one location. Procedures for system bonding vary between on-grid and off-grid systems.

System bonding for on-grid systems
The Conext XW Pro or XW+ does not connect the neutral to ground. The AC input neutral is already bonded to ground by the incoming utility grid system. Do not connect the neutral to ground in any additional location. The Conext XW Pro or XW+ does not switch or disconnect the AC neutral in any mode of operation, so even in invert (back-up) mode, the inverter load sub-panel neutral is bonded to ground by the utility grid system. It must not be grounded again in the inverter load sub-panel.

System bonding for off-grid systems
In a system without a generator, or with a generator that does not provide a grounded neutral, you must make the connection from neutral to ground in the inverter load sub-panel or main distribution panel, as applicable. In a system with a generator that provides a grounded neutral, no additional connection from neutral to ground is needed. Do not connect neutral to ground in the inverter load sub-panel or main distribution panel, as applicable. For more information regarding installations with a generator, please refer to Schneider Electric’s manual for the AGS.