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Should I connect the battery negative to ground inside ac fusebox?

natdak

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Hello,
Im setting up my off grid solar system and Im in the process of connecting the inverter to the main and existing fuse box of the house.
The AC is connected to earth. The AC neutral buss-bar is connected to the ground inside the main fuse box. The battery negative, solar panels, charge controller and inverter are all unearthed currently. My question is how do I connect these to ground? Do I connect all of those together and then take a cable into the AC fuse box buss bar? Or do I first disconnect AC neutral and ground before doing that to make it so called "floating"? Or do I connect to a separate grounding rod? What is a ground fault protector GFP and do I need it? is it the same as an earth leakage circuit breaker ELCB? I intend on using an ELCB for the AC.
 
What inverter?
Do you know if the inverter is internally neutral bonded?

The AC panel I believe should have a grounding rod connected to the panel but the inverter should provide the N/G bond under inverter power. If you have a generator tied in to the AC distribution panel there should be a means of transferring the N and G to the generator for bonding. The source is what is supposed to connect the N/G aka White/Bare.

The battery negative, solar panels, charge controller and inverter are all unearthed currently. My question is how do I connect these to ground?
The solar panels should have their frames connected to a ground rod at the array.
Someone else will need to affirm and perhaps cite NEC but IIRC but they also need a separate panel frame to Bat(-) busbar conductor which also is connected to a ground rod at or near the battery bank. The chassis lugs of both the inverter and charge controller should be connected to the neg(-) busbar.

I’m not suggesting departing from NEC but the solar panels “will operate fine” without the extra ground cable to the building. This need, or not, was debated several times a while back in a thread here. An EE cited the NEC on that but I don’t recall the details or the threads at the moment.

I’m hoping that the minds here will appropriately affirm or correct the information I’ve posted.
 
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Why are you fken wit the main panel if you "off grid"?
Let us start with; What inverter do you have and do you plan on powering your whole house?
 
What inverter?
Do you know if the inverter is internally neutral bonded?
Hey and thanks for the answer. The inverter is a photonic universe 2000w IP2000. I dont know if they are connected inside. It says in the manual: "For vehicle, boats or other mobile systems with negative common ground, use the earth cable (yellow/green if supplied with the inverter) to connectthe inverter case and the negative common ground of your system. For stationary systems, use a suitable ground connection for earthing the inverter case. Note: this inverter cannot be used in positive ground systems" But I think they are talking about the DC side right? Is there a way that I can test?
The solar panels should have their frames connected to a ground rod at the array.
Someone else will need to affirm and perhaps cite NEC but IIRC but they also need a separate panel frame to Bat(-) busbar conductor which also is connected to a ground rod at or near the battery bank. The chassis lugs of both the inverter and charge controller should be connected to the neg(-) busbar.
I didnt quite understand what you are suggesting. Are you saying the panel frames, battery negative, inverter chassis, charge controller chassis and a ground rod (that is separate from the ac ground rod) should all be connected to one bus bar?

Thanks a lot,
Nathan
 
For anyone else wondering in.
Do not connect battery negative or positive to earth, ever.
 
For anyone else wondering in.
Do not connect battery negative or positive to earth, ever.
Can you elaborate? I'm trying to get clarification as NEC code says it must be for 48v+ which means the PV lines and 48V battery bank (Actually 53v) should be grounded.
 
All the setups I've seen so far do not have the AC and DC grounded together. That just sounds like a bad idea.
 
Take a look at the grounding principles of DC wiring, inverters and multiple power sources

 
Please explain why.
I simply said it sounds like a bad idea. Mixing AC and DC can lead to bad things. I know it is simply the ground, but still, it gives me pause. Some things are supposed to remain isolated from each other. Maybe this is not the case here. If I'm wrong, I'm willing to learn why, if you're willing to tell me why.
 
I simply said it sounds like a bad idea. Mixing AC and DC can lead to bad things. I know it is simply the ground, but still, it gives me pause. Some things are supposed to remain isolated from each other. Maybe this is not the case here. If I'm wrong, I'm willing to learn why, if you're willing to tell me why.
I understand you have to do what you think is right, but your reasons sound like fear uncertainty and doubt(FUD).

This document explains things.

My setup is grounded via my inverter
negative_busbar->inverter_equipment_ground->building_ac_ground->building_earthing_system->the_planet.
Keeps my system referenced to the earth.
Since I'm 130 feet off the ground, its the most practical way.
 
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Thank you, I'll read on it. I've worked on primarily AC stuff, 12VDC car stuff, and then a range of 5-24VDC home electronics. This side of things is new-ish to me.
At first glance it seems like everyone is using the wrong color negative wire. Hm, welding cable seems like it comes in red and black. What's your solution to this? Wrap the whole wire with white tape? Just the ends? Different source of wire?
 
Thank you, I'll read on it. I've worked on primarily AC stuff, 12VDC car stuff, and then a range of 5-24VDC home electronics. This side of things is new-ish to me.
At first glance it seems like everyone is using the wrong color negative wire. Hm, welding cable seems like it comes in red and black. What's your solution to this? Wrap the whole wire with white tape? Just the ends? Different source of wire?
AC voltage (120-240 vac) black is hot

DC (low voltage) black is negative, red is positive.
I don't think DC colors are actually specified for any specific colors at low voltage, but this is standard.
 
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