Last check for ground plan of my offgrid system

[jimmy747]

Hello everyone,
Exciting today I received my Growatt SPF 5000 ES Inverter. I spent a good amount of time reading posts on grounding but I haven't found a similar configuration with a confirmation.
My house has a brand new main electrical panel. It has a 18mm (I think it is like a 6 AWG) insulated ground going outise to a copper water pipe. From that ground/wire pipe connection to the street copper pipe I have a resistance of 4 homs so I believe I have a pretty good ground for the house. Also tested at home with a plugin ground tester. As you can see in my diagram from the roof panel to the combiner box, to the AC output panel to the Growatt everything is connected to the same house ground. Is this a safe configuration? I am relectant to add a ground rod and cause a ground loop. Thank you in advance.

 

[timselectric]

That's looks good to me.

 

[sunsurfer]

So is this a hybrid setup since there is a grid connect? You mentioned off-grid and I was looking to see an off-grid grounding setup.

 

[timselectric]

So is this a hybrid setup since there is a grid connect? You mentioned off-grid and I was looking to see an off-grid grounding setup.

Not hybrid , off grid with grid for backup.

 

[BentleyJ]

No need to comment further on the layout, if timselectric says its good, then it is.

Was curious about the voltage in Aruba. We have a timeshare at the Marriott and they use std. American duplex outlets and GFCI near the sinks. Wife's hair dryer works normally with no adapters. Wikipedia says the 3 phase is 220V and residential is 127V. Your set up appears to have only 3 wires, ground and 2 hot or (hot & N) rather than the 3 wire, (2 Hots & 1 N) split phase. Your post lists the Growatt output at 230V. I just had to ask. Hope you don't mind the maybe stupid question, lot of contradictions here.

BTW, Aruba is our favorite even though its a much longer flight from CA than to HI. We actually sold the HI and kept Aruba.

 

[timselectric]

Based on the drawing it's a typical European style (AKA everywhere except North America) 230v single phase. L, N, G.

 

[jimmy747]

That's looks good to me.

Thank you

 

[jimmy747]

So is this a hybrid setup since there is a grid connect? You mentioned off-grid and I was looking to see an off-grid grounding setup.

Well good point. I call it semi-off-grid. Because the Growatt EFS 5000 ES is not designed and will not feed the grid with surplus electricity. BUT in my diagram you see a connection (on way) from grid to inverter because if the panels don’t produce enough watts for the demand it will use some from the grid (in the case of a no-battery installation). Can’t wait to try it. I hope it’s more clear.

 

[glandpuck]

My comments: I would place the DC disconnect switch after the combiner box. I would try to use a "real" combiner box like a Midnite solar combiner box. I would use UL listed breakers in the combiner box of suitable DC voltage rating. I would add a DC rated lightening arrestor to the combiner box. I would place a grounding rod into the ground at the array unless rooftop. I would ground the array separately from the home water pipes as well as ground the combiner box also to that same ground rod. I would install an AC rated lightening arrestor into the sub panel. Lastly, I would place a DC rated fuse between the inverter and the Blue Sea systems ON/OFF switch going to the battery and the inverter. Fuses protect batteries, a breaker does not.

But, you do what you want and what the smart persons tell you to do.

 

[jimmy747]

No need to comment further on the layout, if timselectric says its good, then it is.

Was curious about the voltage in Aruba. We have a timeshare at the Marriott and they use std. American duplex outlets and GFCI near the sinks. Wife's hair dryer works normally with no adapters. Wikipedia says the 3 phase is 220V and residential is 127V. Your set up appears to have only 3 wires, ground and 2 hot or (hot & N) rather than the 3 wire, (2 Hots & 1 N) split phase. Your post lists the Growatt output at 230V. I just had to ask. Hope you don't mind the maybe stupid question, lot of contradictions here.

BTW, Aruba is our favorite even though its a much longer flight from CA than to HI. We actually sold the HI and kept Aruba.

Not a stupid question at all. I’ll do my best to answer. In Aruba houses receive 3 phases. What we know in the states as 110V 120V standard outlets here I measure 130V ! Appliances run fine but I run my network and home automation on a UPS delivering steady 110V. As far as my drawing showing 230V is my AC split inverter run off a double breaker (2 hot). I only want that out of the inverter. After all AC is what ramp up a bill fast in Aruba. BTW good choice keeping Aruba!

 

[timselectric]

because if the panels don’t produce enough watts for the demand it will use some from the grid (in the case of a no-battery installation). Can’t wait to try it. I hope it’s more clear.

If in SBU mode.
Solar and battery cover the loads. If the battery gets low, it switches to grid.
In SUB mode.
Solar and utility cover the loads. Battery isn't used unless utility and Solar can't handle the loads.
Batteryless operation is also an option in this mode.

 

[timselectric]

I would place a grounding rod into the ground at the array unless rooftop. I would ground the array separately from the home water pipes as well as ground the combiner box also to that same ground rod.

Electrical grounding is for safety. The grounding system is at the house.
Earthing is not grounding. By not grounding the array, you will increase the chances of someone getting hurt.

 

[jimmy747]

My comments: I would place the DC disconnect switch after the combiner box. I would try to use a "real" combiner box like a Midnite solar combiner box. I would use UL listed breakers in the combiner box of suitable DC voltage rating. I would add a DC rated lightening arrestor to the combiner box. I would place a grounding rod into the ground at the array unless rooftop. I would ground the array separately from the home water pipes as well as ground the combiner box also to that same ground rod. I would install an AC rated lightening arrestor into the sub panel. Lastly, I would place a DC rated fuse between the inverter and the Blue Sea systems ON/OFF switch going to the battery and the inverter. Fuses protect batteries, a breaker does not.

But, you do what you want and what the smart persons tell you to do. Could you put a link where to buy the

Thank you for your reply. I’ll try to understand your suggestion. Yes it is roof top. Ok if it is safer to put the disconnect switch after combiner box I’ll do that. Could you provide me a link of what to buy for the lighting arrestor? Planting a 6 foot copper rod next to my house will cost $$$$$. Need special machine. In Aruba my house is sitting on coral lava rock kind. Any other options?

 

[timselectric]

As far as my drawing showing 230V is my AC split inverter run off a double breaker (2 hot).

If this is the case. There is going to be a problem.
The Growatt SPF-5000-ES is a 230v L, N, G system.
Unless you have purchased it from Signature Solar (adapted for split-phase systems), as soon as the unit switches to battery. There will be a dead short.

 

[jimmy747]

If in SBU mode.
Solar and battery cover the loads. If the battery gets low, it switches to grid.
In SUB mode.
Solar and utility cover the loads. Battery isn't used unless utility and Solar can't handle the loads.
Batteryless operation is also an option in this mode.

Yes. Great! Love it!

 

[jimmy747]

Electrical grounding is for safety. The grounding system is at the house.
Earthing is not grounding. By not grounding the array, you will increase the chances of someone getting hurt.

For a minute I thought my plan was good to go. Now not sure. I read in this post if timselectric says its good, then it is. but when I read « by not grounding…. » I get confused can you please elaborate? Thank you.

 

[timselectric]

For a minute I thought my plan was good to go. Now not sure. I read in this post if timselectric says its good, then it is. but when I read « by not grounding…. » I get confused can you please elaborate? Thank you.

The grounding system begins at, and is created by the N/G bond. This is either done at the grid service first means of disconnect. Or provided by the utility provider. To ground something electrically, means connecting it to this grounding system. (As in your drawing)

Driving a separate ground rod and connecting anything to it. Doesn't ground it. It only connects it to earth.

 

[timselectric]

I'm more concerned about what your grid system is.
Brown, blue, and yellow/ with a green stripe. Is the standard color code for 230v single phase L,N,G.
And is what your Growatt is designed for.

 

[jimmy747]

The grounding system begins at, and is created by the N/G bond. This is either done at the grid service first means of disconnect. Or provided by the utility provider. To ground something electrically, means connecting it to this grounding system. (As in your drawing)

Driving a separate ground rod and connecting anything to it. Doesn't ground it. It only connects it to earth.

Thank you timselectric. I understand and agree with you. I need to investigate why in Aruba we don’t bound ground and neutral at the first means of disconnect. My 3 phases wires go from the street meter directly to my principal panel which to me is my first means of disconnect. When I changed the panel last week I was surprise to see that the neutral was not bond to the ground. Tomorrow I will reach out to local electricians and investigate why?

 

[jimmy747]

I'm more concerned about what your grid system is.
Brown, blue, and yellow/ with a green stripe. Is the standard color code for 230v single phase L,N,G.
And is what your Growatt is designed for.

Yes. Here it is. Yellow/green ground. Blue neutral and L brown