hamburgerman
New Member
- Joined
- Aug 9, 2021
- Messages
- 28
My county requires me to have a 3rd party provide engineering docs for our solar. We're doing a Sol-Ark 15k, and and it will be connected to 3 arrays, each consisting of 16 390w panels, in a 2(p)8(s) config.
I've engaged a company to do it, and provided detailed drawing and specs based on all my research and (admittedly far from expert) electrical knowledge. I've had to have them correct a few things, but one point still stands, and I am curious if I'm wrong, or they are, so a 2nd opinion would be great!
These are going to be ground mounted, with underground conduit with a total max length of about 200'. When the original drawings came back, they had messed up, and drawn out 6 separate arrays, each with 8 panels in series. No biggie - but they also called for 8 AWG cable for each, back to the inverter.
I called out the wiring issue, but also questioned the wire size. I referenced the spec sheet (attached) showing that even under 100% absolutely perfect conditions, a 2(p)8(s) config here should only ever see a max of 28 amps... so realistically, never even that much. So I asked why on earth they were using 8 AWG for the original drawing, when it was mistakenly ignoring the paralleled strings, thus meaning that would have only ever seen a theoretical max of 14 amps or so.
I asked them to fix the wiring, but then asked why I can't use 10 AWG (and, especially why they hadn't in the first version). They said that the first one had to be 8 AWG because "all of the wires in a single conduit", which I have no idea if that's true or not so I'm willing to accept that. For the revised version, they still said it had to be 8 AWG because "with the parallel config, current goes up." Well yea, I know that, I explained all that and showed my calculations in my preceding message.
I get that 8 AWG won't hurt anything other than costing ~$600 in wire. But, do I really NEED 8 AWG? Am I just misunderstanding or doing my own math wrong in thinking 10 AWG is sufficient?
I've engaged a company to do it, and provided detailed drawing and specs based on all my research and (admittedly far from expert) electrical knowledge. I've had to have them correct a few things, but one point still stands, and I am curious if I'm wrong, or they are, so a 2nd opinion would be great!
These are going to be ground mounted, with underground conduit with a total max length of about 200'. When the original drawings came back, they had messed up, and drawn out 6 separate arrays, each with 8 panels in series. No biggie - but they also called for 8 AWG cable for each, back to the inverter.
I called out the wiring issue, but also questioned the wire size. I referenced the spec sheet (attached) showing that even under 100% absolutely perfect conditions, a 2(p)8(s) config here should only ever see a max of 28 amps... so realistically, never even that much. So I asked why on earth they were using 8 AWG for the original drawing, when it was mistakenly ignoring the paralleled strings, thus meaning that would have only ever seen a theoretical max of 14 amps or so.
I asked them to fix the wiring, but then asked why I can't use 10 AWG (and, especially why they hadn't in the first version). They said that the first one had to be 8 AWG because "all of the wires in a single conduit", which I have no idea if that's true or not so I'm willing to accept that. For the revised version, they still said it had to be 8 AWG because "with the parallel config, current goes up." Well yea, I know that, I explained all that and showed my calculations in my preceding message.
I get that 8 AWG won't hurt anything other than costing ~$600 in wire. But, do I really NEED 8 AWG? Am I just misunderstanding or doing my own math wrong in thinking 10 AWG is sufficient?