Solar Wire for my ground mount

[Gold Country Russ]

#8 THHN (aluminum) online Cut to length red or black $.28 ft. Why not, it will be underground in conduit anyway.

 

[ElkPicture]

#8 THHN (aluminum) online Cut to length red or black $.28 ft. Why not, it will be underground in conduit anyway.

Interesting... Do you have a link? I wonder if that would be harder to pull through?

 

[timselectric]

That makes sense. This is very helpful! I'll plan on running a ground wire.

Do you think #10 THWN wires would work for my 2 strings of panels? 5 wires total. They are the largest bi-facial panels I can find. (Up to 15 amps on each string...running 150 feet).

For my grounding wire I was going to use #6 bare copper from my panels into a junction box and then use #10 green THWN under ground over to the ground bar on my inverter, which connects to my house ground and GN bond. Does this sounds ok for my ground?

Thanks.

Yes, this all sounds fine. Except for the bare copper ground wire. You will have to take extra care that it doesn't touch the aluminum solar panel frames. As copper and aluminum contact will result in galvanic corrosion.

 

[ElkPicture]

Yes, this all sounds fine. Except for the bare copper ground wire. You will have to take extra care that it doesn't touch the aluminum solar panel frames. As copper and aluminum contact will result in galvanic corrosion.

ah. Gotcha. Do you think I should use aluminum THHN as suggested by @Gold Country Russ ? I'll also have an aluminum frame so the copper would need to connect to aluminum somewhere... is that bad? Thanks.

 

[Nobodybusiness]

It will be difficult to beat the big box stores on THHN in 250 ft spools, some local electrical supply stores can occasionally.
I also use wireandcableyourway.com for specific lengths, sometimes that is cheaper.

That’s who I used.

10 AWG Solar Photovoltaic Wire 2KV UL 4703 (PV Wire)

10 AWG Solar Photovoltaic Wire 2KV UL 4703 (PV Wire)

www.wireandcableyourway.com

 

[timselectric]

Do you think I should use aluminum THHN as suggested

That's up to you. I personally avoid aluminum wiring whenever possible.

I'll also have an aluminum frame so the copper would need to connect to aluminum somewhere... is that bad?

The lugs that you use have to be dual rated for aluminum and copper.

 

[ElkPicture]

Which is more likely: Someone touching the panels and getting zapped, or lightning hitting the panels and conducting it all the way back to your house? Direct lightning strikes cannot be mitigated, period. Safety grounding and lightning protection are two separate concepts, and they may work against each other.

But static buildup can be dealt with with beefy surge protectors like the midnite solar MNSPDs.

And don’t you think if the lightning is that determined that it will just follow the + and - conductors anyway?

Because my panels are located 100 feet away from my house and any other AC power won't it be nearly impossible to get shocked by AC Power. If AC power is going out to my panels thru the solar wires, how can I detect this? Using my meter, wouldn't I have to connect one prob to my solar panel frame and the other end 100 feet back to my house Ground/Neutral. and isn't that what someone would have to do in order to get shocked? Is that correct? Just trying to understand better. Thanks

 

[ricardocello]

120V on the PV line?? Discussion of Will's video

@Will Prowse just did a video warning folks about 120V showing up on the PV lines. There have been several threads where people reported seeing voltage on the PV out. I always thought it was failed units, but Will reports it is normal on a lot of units. I can kinda understand if the 120V...

diysolarforum.com

120V on the PV line?? Discussion of Will's video

Even Will admits that there wasn't any consistancy between all the units he tested. It looks like you scored a good one. Good to have more checks posted! ? True. But the inconsistency makes it more scary than if they were all doing the same thing. On the other hand, I can't see that I would...

diysolarforum.com

Not grounding panels

What happens if I don't ground the solar panels? Just realistically speaking. I'm in an area that rarely if ever gets lightning. I'm putting the system together little by little. Haven't set up the inverter yet

diysolarforum.com

I got a small electrical shock when grounding solar panels. Why?

I was connecting 3 strings of solar panels to ground. I started connecting the panels frames together BEFORE making the actual ground connection and i got a small electrical shock when i touched the back of one panels with my bare (and a bit sweaty) hands. It was probably 40-50 v dc but i was...

diysolarforum.com

 

[Gold Country Russ]

Interesting... Do you have a link? I wonder if that would be harder to pull through?

https://www.ktool.net/thhn-thwn-2-1/?page=2 Sorry it took so long; I have no excuse. Aluminum would be a little stiffer but use liberal amounts of pulling lube and it will be fine. Do not ever use aluminum wire without "Noalox" or something similar on the bare wire ends when connecting. 4x150'x$.28=$168. + the ground. If this price .28' is real I would use it, instantly. I know Tim doesn't approve but it's not his money, sorry Tim.

 

[LydMekk]

Alu cable is the Devil's own invention...
I would never use that for a PV run.
But, thats me. Transmissability(hm...) is bad in Alu vs. Copper.
Copper 4mm2 for that length should be good.
Over 150-200 feet/50-70m I would use 6mm2.
As a rule of thumb.

This summer I will run around 200m or 600 feet in conduit with copper and 4 pairs plus a CAT6 for future use.

 

[42OhmsPA]

https://www.ktool.net/thhn-thwn-2-1/?page=2 Sorry it took so long; I have no excuse. Aluminum would be a little stiffer but use liberal amounts of pulling lube and it will be fine. Do not ever use aluminum wire without "Noalox" or something similar on the bare wire ends when connecting. 4x150'x$.28=$168. + the ground. If this price .28' is real I would use it, instantly. I know Tim doesn't approve but it's not his money, sorry Tim.

Thanks for the follow up. They have some great prices on copper THHN.

 

[kscessnadriver]

Heck, wireandcableyourway has 4AWG AL XHHW-2 listed for $0.29/ft, if you really need something with a bit more current carrying capability.

 

[Nan_wpg]

That's earthing, not grounding.
You are not going to the ground rod at the house. You are connecting to the grounding system at your house. (Where the N/G bond is)

Isn’t connecting to the grounding system at the house the same thing as connecting to the ground rod at the house that the grounding system is connected to?

In a post of mine you said it,was ok to connect my array EGC directly to the ground rod (not a seperate ground rod but the rod that my grounding system connects to) rather than all the way to the grounding system bus (because it’s a shorter run and I have wire on hand)

 

[timselectric]

Isn’t connecting to the grounding system at the house the same thing as connecting to the ground rod at the house that the grounding system is connected to?

In a post of mine you said it,was ok to connect my array EGC directly to the ground rod (not a seperate ground rod but the rod that my grounding system connects to) rather than all the way to the grounding system bus (because it’s a shorter run and I have wire on hand)

Yes
Everything connected to the grounding system is part of the grounding system. And can be used as a connection point for future grounding. As long as it's of adequate size for what is being added.
The purpose of the entire grounding system is to provide a low impedance (resistance) path for fault current, back to the source. (Through the N/G bond)

 

[timselectric]

For clarification.
The grounding system isn't connected to the ground rod.
The ground rod is connected to the grounding system.