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diy solar

Is this string box wired correctly?

AgroVenturesPeru

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I'm planning to put up 12 panels on my roof in a 4s3p configuration.

These are the specs of each panel:
Vmp= 40.16
Imp= 9.96

I'd like to see if this combiner box is properly set up, which I was sold by a company. What amp size are the fuses? I can't really tell, but I was expecting 3, 15A fuses. I'm not sure what the other components are on the inside either.
 

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1) Just flip open those 3 light grey fuse holders to see what size fuses are installed. What does the sticker on the solar panel show regarding to the fuse size for the panel?
2) The green box is the surge protection but I do not see the ground wire connected to it.
3) Who put this combiner box together? Does it come with wiring instruction?
 
1) Are you talking about where the negative wires are attached? How do you just "flip open" those things?

2) Ah okay, that makes sense...that's for lightning strikes, right? There's no cable attached yet for that.

3) The box was put together by the solar distributors I bought my components from in Lima, Peru. Their goal is to provide a "plug and play" system for the customer. Most everything has already been sized, wired, crimped, etc. But I need to double check their work, and also learn how to do it myself. They don't have very good customer service down here. For example, I was supposed to have been given a diagram showing a recommended installation arrangement of all my different components, but I had to remind them today. I've just been sitting on this system since the new year due to many delays with building my house.
 
"1) Are you talking about where the negative wires are attached? How do you just "flip open" those things?"
No, I am talking about the 3 light grey boxes on the left of the pictures #1 where the RED wires from PV panel are attached to. Do you see the tab where the red letter 'E' (I belive it is an 'E') is, you just pull the tab down toward you.
DIN rail fuse holder_3.jpg

DIN rail fuse holder_1.jpg
 
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Well, thanks for pointing me in the right direction.

Typical experience down here dealing with the distributor. Now that they have the money, they just sit back and not answer any of the customer's questions. All too common behavior in this country. Nevermind the fact that the invoice they billed me says they include the engineering, configuration, integration and setting of parameters according to the customer's preference. It also includes "arming the battery cables according to the configuration of the system."

I asked them three simple questions exactly one week ago, and followed up with a phone call, so they created a whatsapp group chat with their in-house electrical engineer and technician in order to supposedly respond to my inquiries. During the phone call, their representative, Anthony, attempted to discourage me from doing the installation myself, saying that someone needs to be "qualified" to put everything together. To date, however, they haven't answered a single one of my questions, and instead of responding to the questions they just went ahead and told me I can pay someone to come out (and cover their travel expenses + room & board) to "help me". Not even paying so they can do everything, but just so someone can come out and help me do it.

I will update my thread accordingly, and refrain from making a post specifically about this distributor if they actually turn things around, and stop trying to squeeze more money out of me. I already paid about $4000USD more than what these same components would cost in the USA, so I would expect much better technical support out of the gate to make up for the exorbitant fees one has to pay in this country for anything imported.

In case anyone's curious, the distributor is Novum Solar in Lima, Peru.

https://novumsolar.com/

If their marketer knows anything about google alerts, maybe they'll find this thread and tell their general manager. I for one can't get ahold of the guy.

****Edited to add****
Looks like the secretary told them I was losing my patience, so they put me in touch with their electrical engineer. He was pretty helpful in answering some of my questions, so it looks like they're turning things around.
 
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Given that this box is for the PV panel wiring (Direct Current), that doesn't sound too promising
Can you take good clear pictures of the fuse holder so I can read the prints on it?
So how are yiou going to finish the project if the company is not helping you?
 
Look at 2:18 time line to see how you flip out the fuse.
Thanks Bud.

Here's the answer. Whether or not it's 15 amps meant for direct current or alternating current, I couldn't say. But we're going to use it for direct current, so hopefully they work.
 

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Can you take good clear pictures of the fuse holder so I can read the prints on it?
So how are yiou going to finish the project if the company is not helping you?
They are good clear pictures, but this forum downsizes it automatically. Let me try a workaround.IMG_2510.JPGIMG_2510.JPGIMG_2510.JPG
 
One other concern I have with this string box is the gauge of wire they're using after paralleling the strings: 4mm squared. (~12AWG)
After combining the series into three parallels, the output amperage will be roughly 30amps.
According to this table (for a distance up to 10ft) the cable should be at least 10AWG
According to this table (for a distance up to 10ft) the cable should be 6AWG

Maybe the wire I'm using exceeds the expectations of wire quality they had in mind when making those charts?
My PV wire looks to be pure copper rated to 90 degrees celcius. Here's some photos of my PV cables. I wish I knew what everything meant. "N2xOH"? "29/07D"?
"Nominal Tension: 0.6/1kV"?

IMG_2538.JPGIMG_2536.JPGIMG_2539.JPG
 
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Your combiner box is really pushing it trying to handle 30A (4s3p) with the wires and the MC4 they are using, MC4 connector max currating is 30A (UL rated at 20A).
The wires in your pcitures are the right type for solar application but only 12AWG (4mm).
I cannot read Spanish:
 
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Closer to 11awg (4.17mm^2) & 90°C insulation. I wouldn't have any qualms about running this @ 30A provided the voltage drop is acceptable.
 
Think its been mentioned, but don't see a DC rating on the circuit breakers for in post 11. Using AC circuit breakers in a DC circuit can result in fire. With the way the AC C/B work, may not extinguish the ARC that DC makes. I can't post videos from where I'm at (my issue with network security) but there are some quite entertaining videos on YouTube telling you why not.
 
Think its been mentioned, but don't see a DC rating on the circuit breakers for in post 11. Using AC circuit breakers in a DC circuit can result in fire. With the way the AC C/B work, may not extinguish the ARC that DC makes. I can't post videos from where I'm at (my issue with network security) but there are some quite entertaining videos on YouTube telling you why not.

Aren't those fuse holders that just look like breakers?
 
Your combiner box is really pushing it trying to handle 30A (4s3p) with the wires and the MC4 they are using, MC4 connector max currating is 30A (UL rated at 20A).
The wires in your pcitures are the right type for solar application but only 12AWG (4mm).
I cannot read Spanish:
I know Spanish, so ask me what I'm supposed to look for on that link?
One thing it says is this:
"El aislamiento de polietileno reticulado permite mayor capacidad de corriente en cualquier condición de operación"

Which means "The reticulated(?) polyethylene insulation permits greater current capacity in any operating condition."

To me it's just marketing jargon. Why not just give a chart as to how many amps the wire can carry at a given gauge and distance?

You must speak engineer or at least technician, so please tell me what UL 2556 means.
 
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