Ground strap between rail splices - build my own?

[jeremylmartin]

I just realized I didn't order the ironridge ground strap that is designed to go at the rail splice (for some reason I thought the splice grounded the rails together but that must have been a different rail system I read about). I was going to install this weekend if weather cooperates. Can I use some bare 6 awg copper wire and clamp ends on to make a strap and then attach to each rail with self tapping screws or am I better off pushing the install back a week and ordering the straps? Also, I have read about running 2 grounds, 1 direct to a ground rod and 1 to the ground in the panel. Do I need both? I planned to just go to the ground in the panel.

[emartin00]

It depends on how strict your inspector is really. There is nothing wrong with using 6 awg copper and a lay in lug at each end. As long as you use a properly listed lug, and install it correctly.
I'm not sure I understand what you mean by a "clamp end" though

[jeremylmartin]

Sorry, I am not sure I explained it well. I am using Ironridge rails to mount to roof. There will be 2 splices (40' total length of rail using 3 sections). They sell a ground strap that connects at the splice to carry the ground over the splice. This is the part I forgot to buy.

GR.JPG

GR2.JPG

So I was thinking of making a similar jumper with bare copper wire rather than delay the install. But not sure if the ground they sell is "special".

[foo1bar]

So I was thinking of making a similar jumper with bare copper wire rather than delay the install. But not sure if the ground they sell is "special".

Do you have extra ground lugs for the rails?
At least I assume you are planning on putting in lugs on the rail that tie it to the EGC that goes to your inverter.
If you have extra lugs, you can just run the ground wire over to the other side of the splice, and into a lug on the other side of the splice.
(probably a little more expensive since it'll be extra wire, and extra lugs)
Ironridge allows you to have only one lug per pair of rails (assuming you're using grounding mid clamps)
The pair of rails are tied together via the clamps.
So if you ordered one lug per rail, and you have one splice per pair, you would have enough lugs to do it that way, and I don't think an inspector would object.

If you haven't started yet, I'd probably plan on working this weekend getting the feet and the rails in place, and be happy if I got to that point.
You can install the jumpers after you have the rails on the roof, and have everything positioned (the rails straight, level, etc)

I would NOT just wrap copper around a self-tapping screw on each side and think that's good enough... I dont' think it would be.

[Samsolar]

I'm sure you can find many suppliers that will ship priority mail. Just order the ground straps Thursday and they should arrive Saturday. They are smaller than you might think and can ship in a small cardboard envelope. They are also easy to add after the racking is installed but before the panels go on. Just make sure you don't locate the self tapping screws too far apart.

[emartin00]

I would NOT just wrap copper around a self-tapping screw on each side and think that's good enough... I dont' think it would be.

Absolutely DO NOT do that. You do not want copper and aluminum in contact with each other. They will corrode and fall apart in just a couple years.

[jeremylmartin]

Thank you all for the advice. The weather looks bad this weekend so I ordered the grounding straps and will plan for next weekend. For the record, I am not quite crazy enough to just wrap grounding wire around a screw and think that'll hold for 20+ years. My thought was to crimp a steel eyelet on each end of the bare copper and then use a stainless steel star washer and self-tapper to attach to each side of the rail splice (with no copper in direct contact with the rail). I bet it could have worked but doesn't matter now as I ordered the correct part. Plus I'll feel better knowing it was done right.

foo1bar - Thanks for the tip about needing only 1 ground lug per row. I did order 6 thinking I needed 1 per rail.

[sensij]

Thank you all for the advice. The weather looks bad this weekend so I ordered the grounding straps and will plan for next weekend. For the record, I am not quite crazy enough to just wrap grounding wire around a screw and think that'll hold for 20+ years. My thought was to crimp a steel eyelet on each end of the bare copper and then use a stainless steel star washer and self-tapper to attach to each side of the rail splice (with no copper in direct contact with the rail). I bet it could have worked but doesn't matter now as I ordered the correct part. Plus I'll feel better knowing it was done right.

foo1bar - Thanks for the tip about needing only 1 ground lug per row. I did order 6 thinking I needed 1 per rail.

Every splice on a bonded rail needs a ground to bridge it. Ironridge's grounding guide is here for more info. There is nothing special about the ground straps, below is a picture of splices grounded with lugs and bare copper. Eyelets and listed grounding screws / washers would have been fine as well.

splice.jpg

[foo1bar]

Every splice on a bonded rail needs a ground to bridge it. Ironridge's grounding guide is here for more info.

To clarify - ironridge requires a grounding strap bridging the splice on the rails with the grounding lug.
"[grounding straps] are only required on the rail with the grounding lug"

(I clarify because some people would say every rail is bonded to ground, either via lug or via the midclamps and then the lug. )

[sensij]

To clarify - ironridge requires a grounding strap bridging the splice on the rails with the grounding lug.
"[grounding straps] are only required on the rail with the grounding lug"

(I clarify because some people would say every rail is bonded to ground, either via lug or via the midclamps and then the lug. )

Yes, the grounding in the picture is overkill, but probably cost << $100. If the ground path is ever needed, having more copper will only help.