Some Grounding Questions.

[Bongos2k]

I have a few questions about a pending completion of a setup i am making consisting of 600W panels , 12 volt battery bank setup, charge controller and an inverter for AC.

This is for offgrid cabin. - the cabin has an existing portable generator setup with a grounding electrode thru the concrete (both in the basement) and a panel box upstairs leading to a few outlets and such.

The solar system will be completely separate from the generator and not tied together electrically.

So the questions are ; do i make a separate grounding rod ? And if so would i need to bond it to the generator system? Or can i just use generators existing grounding rod?
And for another curve, there is a water well pipe about 12-15ft from the generators ground rod. I do not believe the water system is tied to the generator's grounding rod. The pump for the well is old and has no ground that runs off a plug from the generator.

[Sunking]

No ground is required or needed. Depends on how you plan to implement over current protection devices.

[Bongos2k]

I was going to put a 120A fuse from battery bank to my inverter.
Solar panels will have a 15A fuse coming in ,as well as my ground fault protector followed by a 30A breaker. into the charge controller.

Or am i overthinking this and just need the fuses?(adding a 30A Fuse to the controller to battery as well)
I was essentially mimicking http://www.midnitesolar.com/pdfs/Kid...ries_REV_B.pdf after doing my own digging into what is typically used.
I thought the ground fault protection was required regardless of voltage.
The combined Voc of the 2 panels would be 79.6

[Sunking]

Solar panels will have a 15A fuse coming in ,as well as my ground fault protector followed by a 30A breaker. into the charge controller.

Why????

If you have 2 strings of panels there is no requirement to have anything between the panels and Charge Controller. With only 600 watts there is no reason to have more than 1 single string of panels. If your panels are in parallel, you have made a huge mistake and likely bought the wrong type charge controller.

It is impossible for the panels to deliver any current that could not even make a 12 AWG conductor warm up, nor could it electrocute anyone. Remove the gounded circuit conductors and you eliminate shock. It is a complete waste of money and just makes your system more prone to failure. Bond the frames of you panels with a 12 AWG conductor to the same ground rod the generator uses. That is all the ground protection required, and the irony will likely never be needed as its only purpose is to give lightning a path to earth if one of the panels had a direct strike. No fuse, surge arrestor, GFD, or breaker will prevent any damage, they will be just be more equipment you have to replace that does nothing and has no function in your application.

You need 4 fuses connected as you see below. They are connected directly to the Battery Term Post. Two facing the Charge Controller, and two facing the Inverter. Size the CC fuses to the same amp rating of the controller, and size the fuses to the Inverter no larger than required. Blue Sea has the Fuses you want to use on the battery as that is the source of power, not the panels.

[Bongos2k]

The panels are in series.
Thanks for the advice. I've already got 2 fuses i can use for the inverter side. So i will grab 2 , 30A fuses for the controller.
Instead of running a ground wire ALL the way back into the building, i'll drive a new rod beside the panels.

[Sunking]

All rods in the ground MUST BE BONDED together to form a common Ground Electrode System. So if you are going to sink rods, did the trench for the bonding jumpers to connect distant ground rods. The water pipe is required to be bonded and used as an electrode, especially one from a well with a pump.

Great your panels are in series. They do not need any over current protection devices because solar panels are current sources, extremely limited current sources. Look at your panel specs for a rating like Isc (Current Short Circuit) and Imp (current at max power). Isc will be the larger of the 2. What Isc tells you is the absolute most current the panel is capable of supplying into a dead short circuit. In reality it cannot even do that as Isc is a Lab condition. OK fuses, breakers, and other current interrupting devices only have 1 purpose, to protect the wire they are connected to by preventing short circuit currents from over heating the conductors they protect.

Fuses are sized according to the size of wire you use in NEC applications. Example a 12 AWG copper wire cannot have a fuse larger than 30 amps. In Solar we always over size the wire according to length and current. A 12 AWG wire can handle about 30 amps before it heats up. Anything less is a cool happy happy safe wire that can do that till the sun goes dark.

So here you have a single string of panels. Lets say Isc = 10 Amps, and you use say 12 AWG wire which is happy happy with more than twice that much current flowing. So if you short out the panels where it connects to the charge controller what happens if it is solar noon on a clear and bright summer day? Well if your panels were at full power were providing around 9 amps current and when shorted have 10 amp. So what good is the 15 amps fuse that will never operate because the panels cannot deliver the 40 amps to blow the fuse quickly. No problem for the 12 AWG wire with 10 amps, and if you up sized the wire to make up for power losses you are likely using larger like 10 or 8 AWG which can handle a lot more current.

Now the batteries can deliver a thousand amps or more of current into a short circuit which will vaporize unprotected wires. If you install the fuses directly to the Battery Term Post, everything is protected if you coordinated proper wire and fuse sizes. The battery is the SOURCE of dangerous current, not the panels.

Having said that you can make your system a grounded system. If done correctly you can eliminate the two fuses on the battery Negative Term Post. It would be silly to do so because you have just invited unnecessary outages, equipment damage, expense, potential of electric shock, and lightning into you home as welcomed guest. So below is how it is done. This is what folks do in Vans and RV's as it is less expensive to implement and the dangers all the metal framing presents. But as you can imagine a RV or Van does not have ground rods or lightning to deal with.

[Bongos2k]

Alright. Will do.

[Bongos2k]

So your saying i'm better off leaving the charge controller, battery bank, and inverter unconnected to ground and only grounding the array back to the generator's ground rod , as per post #4 ?
Also is there a distance set that would allow not bonding of GES? (if not, how does one factor in a place with close proximity neighbors?)
In my case the solar array is approximately 100ft away ,and would be separate of anything to do with the generator. Having only a few things plugged into the inverter. No receptacle setup.

[Sunking]

So your saying i'm better off leaving the charge controller, battery bank, and inverter unconnected to ground and only grounding the array back to the generator's ground rod , as per post #4 ?

Yep. The only thing required to be bonded is the Solar Panel Frames in the event they are struck by lightning. Otherwise it has no function. It is forbidden to use earth as a conductor. Only utilities can do that. The ground rod is there to protect you from outside, not from what is inside.

Your generator and inverter are not capable of operating any fuse. Only the battery has the energy to do that. There is no requirement to ground your generator. Your Generator use GFCI receptacles to protect the cables, no ground required or needed.