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Need Advice on Mounting Solar Panels to Wooden Frame and Grounding Off-Grid System

IIRC (i could definitely be misremembering) you are allowed to direct the EGC path differently from the path that the PV conductors follows (specific exception for PV). So presumably that helps SOMEBODY, since the exemption exists.
 
Proper lighting protection for an array isn't cost effective.
It's about the same cost as replacing the array.
It is probably cheaper to insure the array for 20 years.
Personally, I prefer to just cross my fingers. It's the cheapest option.
 
Proper lighting protection for an array isn't cost effective.
It's about the same cost as replacing the array.
It is probably cheaper to insure the array for 20 years.
Personally, I prefer to just cross my fingers. It's the cheapest option.
You are right, it ain't cheap, especially these days. Only reason I have what I do, it is a byproduct from other activities.
 
Thanks Tim, that makes things a bit easier. One conductor for the entire rack, to both inverters.

Just found this thread which I am examining.


It would be based on the 15a. Just like the current carrying conductors.
So 14 gauge copper is what is required.
It only needs to carry the fault current for the circuit. Anything above that would melt the current carrying conductors. And the SCC board.
Just to make sure I have this correct in my tired mind and before I go on a wire hunt around here or have to buy it:

All panels and racks need to be bonded together with a 6 AWG bare solid copper conductor, utilizing stainless bonding lugs of some sort to prevent dissimilar metal issues.

One 14ga conductor from all the bonded racks back to both inverters ground lugs. I think I have a spool of green 10ga THHN in the shop, if that will suffice.

Bonding these panels to my home made aluminum angle racks is going to be a hat trick. I see allot of sandpaper and star washers in my future. I don't think WEEBS will work.
 
All panels and racks need to be bonded together with a 6 AWG bare solid copper conductor, utilizing stainless bonding lugs of some sort to prevent dissimilar metal issues.
Yes, a minimum of #6 is required, if not in conduit. Solid or stranded is fine.
Bare is ok, but copper should not be in physical contact with aluminum. I prefer insulated (green) for this reason.
A dual rated (copper/ aluminum) lug is what you want.
One 14ga conductor from all the bonded racks back to both inverters ground lugs. I think I have a spool of green 10ga THHN in the shop, if that will suffice.
Inside conduit, #14 is the minimum required. But you can go larger if that's what you have handy.
Bonding these panels to my home made aluminum angle racks is going to be a hat trick. I see allot of sandpaper and star washers in my future. I don't think WEEBS will work.
Weebs are designed to bite through any coating or oxidation on the panel frames. Should work with aluminum framed racking also.
A star washer performs the same function. But probably wouldn't pass inspection.
 
Yes, a minimum of #6 is required, if not in conduit. Solid or stranded is fine.
Bare is ok, but copper should not be in physical contact with aluminum. I prefer insulated (green) for this reason.
A dual rated (copper/ aluminum) lug is what you want.

Inside conduit, #14 is the minimum required. But you can go larger if that's what you have handy.

Weebs are designed to bite through any coating or oxidation on the panel frames. Should work with aluminum framed racking also.
A star washer performs the same function. But probably wouldn't pass inspection.
Thanks Tim, back on the hunt.

If I have to buy the 6, might as well get insulated.
 
I don't think WEEBS will work.
Weebs are fine IMO, and for several racking systems they explicitly tell you to use weebs for bonding to aluminum frame. Who are we to say no.

There is also at least one weeb type supposedly for direct bonding of solar panels, and those are also aluminum frame with coating/oxide.
 
Weebs are fine IMO, and for several racking systems they explicitly tell you to use weebs for bonding to aluminum frame. Who are we to say no.

There is also at least one weeb type supposedly for direct bonding of solar panels, and those are also aluminum frame with coating/oxide.
I am sure WEEBS are great for industry standard racks. Just don't think I can get them to physically work/fit on the racks I am building. I am using 1.250 x 1.250 x .250 aluminum angle, the panels will nest down inside the L's. When I priced out racking, it was in the multiple thousands, not to mention footings and all the rest. So far I am into it for just under $1000, plus building it.

Best spit balling I can come up with so far is using 32 Ilsco SGB lugs and 8 more for the racks, ($$$) with four # 6 ground wires coming from 4 gangs of 8 panels/racks, (assuming the grounding wire DOES NOT have to be a one piece, continuous run through all panels) terminating in a plastic box, tied to a 12ga, or 10 or whatever I have laying around, going back to the inverters.

While were at it, what's with #6 on the panels, dropping down to 12ga? Is NEC thinking people will trip over the wires and possibly tear them lose? Exposed to the elements? I plan on all bonding being on the undersides, of the array. What's the best way to terminate four #6's to a single 12/10ga conductor?

I spoke with Ilsco tech and he said that these lugs are tin coated, meaning good for alum to copper connections. Just wish I could find something cheaper and easier. Keeping to code gets expensive.

 
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(assuming the grounding wire DOES NOT have to be a one piece, continuous run through all panels)
Doesn't need to be. In fact you are allowed to bond through panels if you want. I tried not to rely on it too much that b/c that sounded like hack work.

You probably need to find the right kind of Weeb for the thickness of your aluminum angle. The ones that bond panel frames directly just go into bonding holes, but frames are quite thin.

I spoke with Ilsco tech and he said that these lugs are tin coated, meaning good for alum to copper connections. Just wish I could find something cheaper and easier. Keeping to code gets expensive.
It gets more expensive if those are single use Weebs

While were at it, what's with #6 on the panels, dropping down to 12ga? Is NEC thinking people will trip over the wires and possibly tear them lose? Exposed to the elements? I plan on all bonding being on the undersides, of the array. What's the best way to terminate four #6's to a single 12/10ga conductor?
Yes I think #6 is because NEC lets you have them just hanging loose out there, without protection from being inside outdoor rated cable or conduit. The #6 needs to go to all panels.

Normally people drop down to #10 or #12 when exiting the array and into a regular wiring method.

Probably terminal blocks are a good way to get the #6's down to a single one. A lot of solar combiner boxes are built from DIN rail. So following that logic you would have a bunch of grounding terminal blocks next to each other on the DIN rail. So potentially you would go:

#12 -> DIN-style terminal block or US-style Terminal Block screwed directly into box -> 4x #6's -> 4x glands -> exits box.

You might want to do #10 for more future proofing, if you might pull #8 or #10 CCC to the array someday.
 
Thank You for all the advice and help. I have quickly learned that there is more to this than throw it on the ground and plug it in. You two are invaluable and absolutely necessary for the successful conclusion for the proper operation and safety of this system.

I have allot of social events with allot of people and I can just see people walking down to the panels and getting all "touchey feeley" with things.

I need to investigate WEEBS a bit further to see if there is a solution there instead of the Ilsco solution. I also don't like the idea of 4 conductors coming into the box. If I configure this right, I should be able to get down to 2, both being continuous runs.

Off to WEEBS school to try and figure those things out.
 
I need to investigate WEEBS a bit further to see if there is a solution there instead of the Ilsco solution. I also don't like the idea of 4 conductors coming into the box. If I configure this right, I should be able to get down to 2, both being continuous runs.
The nice thing about solar EGCs is that you have a lot of flexibility in how to splice them. It doesn’t have to be done inside a junction box. You can probably even find some weather rated split bolt or similar hardware to splice them together within the array.

Is this a DC or AC system? If people are walking around it I would be pretty anxious even with AC modules/microinverters (AC provides slightly more active protection against weird stuff happening).

Usually when I see solar arrays in public here in California and elsewhere, where there is foot traffic, they are way way up out of the way.
 
These are the new 6000XP's, AIO units. Non isolated that like to bleed AC onto the PV lines.

Looking at WEEBS lugs, the 6.7's, they are just as expensive as the Ilsco lugs. They would also need to be mounted via drilling a hole through both the rack and panel (since the panel lays on the angle) and bolt it on with the piercing plate tucked up in there on the inside of the bottom of the panel frame.

On the other hand:

When I spoke to tech at Ilsco, they said using their lug to clamp both the panel and the rack together would violate NEC. I have to wonder how though, if the piercing pad is scratched into the panel frame, what diff does it make where the other side is? I was still planning to use more of them to bond the rack as well.

ETA: By the same logic, bolting the WEEBS on both the panel frame and through the rack should also violate NEC.

Guess I just need to get some in my hands and see which makes the most sense and work the best.
 
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Bonding can not be part of the mounting. Because if the mounting loosens you lose the Bonding.
The only exception is weebs, which have somehow been accepted for this use.
Keyword - "somehow" wonder who made out on that deal... typical.

An airplane would have to smash into these racks to loosen them up.

Imagine a 13' long panel, 40" wide. This is the panel layout, 2 panels stacked on short sides x 16 stacks of 2, along the line, over 50 feet or so.

If I could keep the bonding runs in the middle of that 13 foot panel, (2 bonds real close) I can keep wire lengths to a minimum and it will look good. But this would mean clamping to the panel and the rack.

If I cant use 2 clamps on two panels near the middle of that 13' where the panels meet, I have to go to the ends and will have 13' wire runs. Just so happens the rack angles are 12.5 feet long and the two panel stacked on top of each other are 13.5 feet. The panels will overhang the rack by a foot or so on each end and this is the only part of the panels I have open access to just the panel frames, with no rack in the way. This will look like crap and I'll have to use an extra 100' of wire, at least. Guess I could use jumpers between the panels and only bond at one end instead of the middle or on both ends.

I am not having this inspected but still want to abide by the code. I have 2 Union electricians at my disposal to handle the AC end of this quagmire.
 
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Keyword - "somehow" wonder who made out on that deal... typical.

An airplane would have to smash into these racks to loosen them up.

Imagine a 13' long panel, 40" wide. This is the panel layout, 2 panels stacked on short sides x 16 stacks of 2, along the line, over 50 feet or so.

If I could keep the bonding runs in the middle of that 13 foot panel, (2 bonds real close) I can keep wire lengths to a minimum and it will look good. But this would mean clamping to the panel and the rack.

If I cant use 2 clamps on two panels near the middle of that 13' where the panels meet, I have to go to the ends and will have 13' wire runs. Just so happens the rack angles are 12.5 feet long and the two panel stacked on top of each other are 13.5 feet. The panels will overhang the rack by a foot or so on each end and this is the only part of the panels I have open access to just the panel frames, with no rack in the way. This will look like crap and I'll have to use an extra 100' of wire, at least.

I am not having this inspected but still want to abide by the code. I have 2 Union electricians at my disposal to handle the AC end of this quagmire.
Just make sure that everything is bonded together. And then the ground conductor only needs to connect to one place.
 
Thanks Tim for your help. Everything else has been resolved pretty eloquently, this however is quickly becoming a cluster ....
 
Just keep it simple. Since you're not needing to pass an inspection.
The goal is to make sure that all metal parts are connected to a path back to your grounding system.
When you bolt the panels to the framing. Put a star washer between the frames. It will bite into both sides and bond them together. (At 4 places per panel) then just attach the ground conductor (at one place) anywhere that is convenient.
 
Living on a knoll and with such a target rich environment, LUCK runs pretty damn thin around here!

Over the years I have installed a few thousand dollars worth of mechanical lightning mitigation systems around here. They have served me well so far. I'm not talking about those little boxes with "special mix) toroid's or beads either. Any one that thinks those things will serve any value against lightning, much less a EMP of duration, is spitting in the wind.

I was thinking of writing up a little description of what I have done around here to mitigate strikes/damage. I have been dealing with lightning for over 50 years in all the data systems design and installations.

ETA: I have noticed searching the forum for "array lightning protection" yields very few results. That's all you need to know...
I would like to see this
 
I would like to see this
Lightning protection is part science and part art. If you want to protect something, give it other, DIRECT, paths to ground.

There isn't really much to see, other than conductors running down towers, a wall or down antenna mast's. Most everything that counts is in the ground. Other than that, I installed lightning arrestors on all high frequency antenna feeds, on the braided shields, to ground. I don't know how well they would do with a strike. A direct hit would blow them to pieces and probably roach anything in the shack that is connected. When storms come around, everything gets pulled if I'm around.

On the mains power, I have some huge MOV's on the incoming mains. These are one shot devices and quite expensive.

Here are some suppliers I have used over the years. NEC has information on mitigation as well.




ETA: Here is an example of proper tower grounding, ironically for a wind turbine. I followed a resemblance of this on 2 towers, as well as using exothermic welds.

https://www.solacity.com/grounding/
 
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30 years ago I worked putting up 400' towers for cell phones. The grounding is extensive. For the guyed towers there was a loop around the main base and control building about 10' out. And there was a loop around each of the bases for the guy wires. And a leg from the center tied to each guy. All done in 4/0 copper with 16' rods (if we didn't hit bedrock) every 20' all thermite welded together.

We also did a few free standing towers but I don't remember what the grounding was for them.
 
30 years ago I worked putting up 400' towers for cell phones. The grounding is extensive. For the guyed towers there was a loop around the main base and control building about 10' out. And there was a loop around each of the bases for the guy wires. And a leg from the center tied to each guy. All done in 4/0 copper with 16' rods (if we didn't hit bedrock) every 20' all thermite welded together.

We also did a few free standing towers but I don't remember what the grounding was for them.
 
So after getting spanked for running off the rails with this thread and on the hunt for grounding hardware for the panel rack I am building, I happened across these. They have to be better than star washers but if each panel needs 4, that's a butt load of scratch for half a handful of stainless, like $170 for 32 panels. Wonder if I could just get away with one or 2 per panel?


Then there are these chicom deals. $15 for 50... With allot more "digging in" contact potential.

 

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