question

a-r avatar image
a-r asked

Main Breaker Panel bond neutral to ground with Multiplus off grid with solar as only input?

I have a completely off grid system with the only energy input being solar panels. I have a Victron Multiplus 12v 3000VA inverter. I want to wire a main breaker panel (and eventually a subpanel from that) to AC-Output 1 on the multiplus. Since I will have nothing feeding AC-Input on the Multiplus, it is my understanding that the Multiplus creates a Neutral-Ground bond inside itself. My question is, if that is the case should the Main breaker panel i am wiring to AC-Output 1 have its Neutral and Ground bonded or not?


Thank you in advance

Grounding
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
gazza avatar image
gazza answered ·

The Neutral-Ground link should happen once... and once only! So, as long as that occurs in the Multi that is sufficient. The PE (earth post) on your Multi should go to your earthing point..?

4 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

a-r avatar image a-r commented ·

That is what I thought, only one instance of neutral-ground bonding is allowable.


the manual states:

The MultiPlus is a safety class I product (supplied with a ground terminal for safety purposes). Its AC input and/or output terminals and/or grounding point on the outside of the product must be provided with an uninterruptible grounding point for safety purposes.

The MultiPlus is provided with a ground relay (relay H, see appendix B) that automatically connects the Neutral output to the chassis if no external AC supply is available. If an external AC supply is provided, the ground relay H will open before the input safety relay closes. This ensures the correct operation of an earth leakage circuit breaker that is connected to the output.


As to your question on earthing point, i assume that is also what the manual is talking about when it says the multi must be supplied with an uninterruptable grounding point. but this wouldnt be a grounding rod would it? as that is for static buildup and lightning? what is the correct grounding point in a system such as i have?

0 Likes 0 ·
gazza avatar image gazza a-r commented ·

Have a look at Chapter 7 in Wiring Unlimited. There are lots of different situations of OFF and ON grid systems. You should find what you need in there?

EDIT: here's a quicker link https://www.victronenergy.com/upload/documents/The_Wiring_Unlimited_book/43562-Wiring_Unlimited-pdf-en.pdf

1 Like 1 ·
a-r avatar image a-r gazza commented ·

Oh yes i read that section of the wiring guide earlier today. For Off-Grid they specify: “Ground close to the battery. The battery poles are supposed to be safe to touch. The battery ground should therefore be the most reliable and visible ground connection.”


What does ground close to the battery mean? short cable runs from equipment chassis grounds and battery negative pole?


here is the diagram accompanying for off grid system:

0 Likes 0 ·
img-4276.jpeg (410.9 KiB)
gazza avatar image gazza a-r commented ·

"What does ground close to the battery mean? short cable runs from equipment chassis grounds and battery negative pole?"

Yes, exactly.

1 Like 1 ·

Related Resources

Additional resources still need to be added for this topic