How to ground my solar panels ?

[Philandviki]

Hi everyone. Im new here and new to solar power. I installed two 45 watt panels on my roof which i built aluminum frames for. From there they come into my garage and into the solar charger which then charges my batteries . From there I have a power inverter off my batteries which I plugged in romex cable in and ran that into my house as you would a normal household socket" everything works great. However how do I ground the system ? When I plug in my electrical tester it obviously shows that I have no ground. How do I ground that system ? Any ideas would be great. I think if it got struck by lightning now everything connected to it would fry ...

[inetdog]

Hi everyone. Im new here and new to solar power. I installed two 45 watt panels on my roof which i built aluminum frames for. From there they come into my garage and into the solar charger which then charges my batteries . From there I have a power inverter off my batteries which I plugged in romex cable in and ran that into my house as you would a normal household socket" everything works great. However how do I ground the system ? When I plug in my electrical tester it obviously shows that I have no ground. How do I ground that system ? Any ideas would be great. I think if it got struck by lightning now everything connected to it would fry ...

Even if you add the best possible ground, a lighting strike would still fry everything. At best you can protect against the induced currents from a nearby strike.

If your house has grid power right now, there is a very good ground connection point at the main panel or main disconnect of your incoming service.
If you run a ground wire from the inverter ground terminal to that point it will give you a good ground connection.
But your receptacle tester may still show no ground if the "neutral" conductor of the inverter output is not bonded to the ground conductor at the inverter. At that point you are into territory which only somebody actually on site and qualified as an electrician can safely advise you. I would not touch that with a 10 foot fiberglass pole.

PS: Welcome to Solar Panel Talk!

[Mike90250]

.... I think if it got struck by lightning now everything connected to it would fry ...

Yep, your house, and all the gear inside it, including your insurance policy when the insurance investigator (yes, they still exist) discovered a bootleg solar install of non-certified gear and power outlet.

I suspect your power inverter is a Mod-Sine inverter, and those CANNOT be grounded properly, usually they fry instantly. (read it's instructions) So the best you can hope for is to use some aluminum rated ground lugs (the brand WEEB comes to mind) and ground only the lowest point of the frame(s) to a ground rod in a simple, direct path to ground. And the local code always varys on what is acceptable.

[Philandviki]

I am using a Cobra CPI 1575 inverter . The instructions say to use 8 awg coper wire (there is a spot on the back of the inverter ) and connect it to a ground rod or other ground from in coming electrical source. I have the ground from my main house as well as a ground rod from my 16kw generator. I guess I could use either .

[organic farmer]

I was doing this today [grounding my panels].

My solar panels are arranged in 6 strings of 3 each. The metal frame-work that holds and supports my solar panel array is grounded.

The Positive leads from each string go to breakers in a combiner box. The Negative leads go to a negative bus-bar in the combiner box. A bare-copper stranded 6awg wire attaches to each solar panel frame, these go into the combiner box, to a ground bus-bar. That ground bus-bar is then attached to it's own separate ground rod [8' copper rod pounded into the ground].

My combiner box also has a 'surge-protector' on it. Which is supposed to drain away lightning spikes that get onto either the Positive bus-bar or the Negative bus-bar. Then when the Positive and Negative lines go into my house, they will both be inside metal conduit, which will be grounded. The panel with the Charge-Controller and Inverter has two separate surge-protectors on it.

I also have two lightning rods. Each is made of a grounding rod in the ground, a second grounding rod up in the air, supported by a steel T-post and 12' of conduit. All connected together by bare-copper stranded 6awg wire. My solar-panel array is 70' long. One lightning rod is erected near either end of the array.



Every part needs to be grounded. If you live in a region known for lightning strikes, then you also need lightning rods above your solar panels.

[Mike90250]

Cobra CPI 1575 inverter . The instructions say to use 8 awg coper wire (there is a spot on the back of the inverter ) and connect it to a ground rod

I don't think Cobra makes any pure sine inverters. You should ground only the PV panel frames. And use the ground post on the inverter to connect it to it's OWN ground rod. Do NOT connect any batteries or neutral wires to ground, or your mod-sine inverter goes boom, and you get a 60V shock.

[inetdog]

I don't think Cobra makes any pure sine inverters. You should ground only the PV panel frames. And use the ground post on the inverter to connect it to it's OWN ground rod. Do NOT connect any batteries or neutral wires to ground, or your mod-sine inverter goes boom, and you get a 60V shock.

I do not see any disadvantage to connecting the ground terminal of the inverter to the building EGC system instead of its own ground rod. In fact, I would rather see that option taken. The AC lines will still be floating if the inverter wants them to be.

[SunEagle]

I do not see any disadvantage to connecting the ground terminal of the inverter to the building EGC system instead of its own ground rod. In fact, I would rather see that option taken. The AC lines will still be floating if the inverter wants them to be.

While I agree that grounding the Cobra inverter "chassis" is a good idea that inverter probably uses the chassis "ground" for the ground terminals on the 120volt outlets.

It might not be a good idea to use the same ground for the inverter that your main power panel uses since the power is coming from two different sources, (battery and Utility).

Also that Cobra does not have GFI circuit protection which is a little more protection in case the ground wire gets some juice going through it. So user be ware.