10 gauge PV transition to regular Copper???

[crcastor]

My plan is to use the PV wire up until the PV breaker box on the outside of the house. Then to use regular copper up the outside wall through the attic over to another cutoff before going into the inverter. Looking for recommended copper gauge size??? (928v 8.9A)
Please be nice I am a newbie ?

 

[zanydroid]

I think most standard building wire is 600v so you want insulation type recommendation in addition to gauge. Gauge also depends on factors like derating for temperature or number of wires per conduit.

 

[crcastor]

The insulation thickness is Something I learned a while back but totally forgot ? Looks like the idea of just running PV through some conduit up in the attic all the way from outside cut off switch to the inverter is probably way to go.

 

[PreppenWolf]

The issue (cost wise) will be the voltage requirement. <10A is nothing. You can run 14 AWG for that assuming the correct insulation.

I personally ran 6 AWG for my 450V 18A runs to future proof it for additions.

 

[12VoltInstalls]

928v ?‍?

That is the number you need to insure your PV wire is rated in excess of.
As mentioned, conduit diameter versus cable count is another element to cross check before you buy.
Also I’m told some solar wire is rated 105*C but most is ~90*C. Even temco- but the UL 10ga temco on amazon is only 600V. PowrMR on amazingzon is published as 1800V oddly enough; there’s no mention of UL…

 

[Zwy]

The issue (cost wise) will be the voltage requirement. <10A is nothing. You can run 14 AWG for that assuming the correct insulation.

I personally ran 6 AWG for my 450V 18A runs to future proof it for additions.

Much depends on the Vmp voltage and the voltage drop due to distance.

14 ga, 10A, 380VDC, run of 420 feet will be 5.87% voltage drop.

10 ga, 10, 380VDC run of 420 feet will be 2.27% voltage drop.

14 ga, 10A, 150VDC, run of 420 feet will be 14.87% voltage drop.

10 ga, 10A, 150VDC, run of 420 feet will be 5.75% voltage drop.

Calculator found here. https://www.southwire.com/calculator-vdrop

 

[PreppenWolf]

True. I should have specified distance plays a role. My runs are less than 100ft

 

[Ampster]

he insulation thickness is Something I learned a while back but totally forgot ? Looks like the idea of just running PV through some conduit up in the attic all the way from outside cut off switch to the inverter is probably way to go.

In my jurisdiction high voltage DC has to be in conduit but I am not sure PV wire is rated for use inside conduit. I also question why your PV panels are wired in a way that they put out that much (928V?) voltage. I do not know too many inverters which can take that much voltage on the PV input. What inverter are you using?

 

[crcastor]

My inverter is an EG4 6000 EX. Two strings of 12 285 w 37v in series solar panels going into one PV input on the inverter

 

[PreppenWolf]

Ok I think you mistyped the opening post. You proposal is 12s2p setup. 24 total panels, 12 panels in series and two parallel strings.

12 panels X 37V per panel is (2) 444V series strings. You need wire to support 444V, which will mean you need to look at 600V rated wire. This is good because it is the most common.

Max input is 500VDC for that unit per the manual (same as my 6500EX) only I notice the 6000 only has one MPPT channel.



How far do you need to run the wire?

 

[crcastor]

Ok I think you mistyped the opening post. You proposal is 12s2p setup. 24 total panels, 12 panels in series and two parallel strings.

12 panels X 37V per panel is (2) 444V series strings. You need wire to support 444V, which will mean you need to look at 600V rated wire. This is good because it is the most common.

Max input is 500VDC for that unit per the manual (same as my 6500EX) only I notice the 6000 only has one MPPT channel.

View attachment 126593

How far do you need to run the wire?

Thank you for your reply it is very informative. Also thank you for having the patience with newbies. I know just enough to probably get me in trouble ?? hopefully with some time I can get the acronyms and electrical solar language down! There are a few other forms out there where the members aren't very nice to those of us you're trying to learn.

 

[crcastor]

Ok I think you mistyped the opening post. You proposal is 12s2p setup. 24 total panels, 12 panels in series and two parallel strings.

12 panels X 37V per panel is (2) 444V series strings. You need wire to support 444V, which will mean you need to look at 600V rated wire. This is good because it is the most common.

Max input is 500VDC for that unit per the manual (same as my 6500EX) only I notice the 6000 only has one MPPT channel.

View attachment 126593

How far do you need to run the wire?

I have to run the wire about 120 ft

 

[PreppenWolf]

Not a problem. I went on a Solar crash course this year and just today a member pointed something out I am now considering as a change to my systems.

Need to know how long the wire run will be to supply advice on gauge/type of wire.

 

[crcastor]

Not a problem. I went on a Solar crash course this year and just today a member pointed something out I am now considering as a change to my systems.

Need to know how long the wire run will be to supply advice on gauge/type of wire.

The wire has to run about 120 ft.

 

[PreppenWolf]

Ok. Bookmark this page for later.

Voltage Drop Calculator | Southwire

www.southwire.com

This page can estimate the real peak voltage of your system based on temperature. Cold makes the voltage go up.

Solar panel maximum voltage calculator - How to work out the max voltage

To get the maximum solar panel voltage you should expect from your solar panel, use our solar panel maximum voltage calculator.

gold-coast-solar-power-solutions.com.au

Also this page is helpful as a reference if you want to print it out and laminate it.

AWG Wire Gauge Chart For All 44 Wires (Ampacity Chart)

Picking exactly the right wire size is not an easy task at all. Different AWG (American Wire Gauge) wires have different diameters, cross-sections, and allow only a limited number of amps to flow through them. To adequately figure out what size AWG wire you need, you require at least a wire...

learnmetrics.com

On your specific question 10 AWG would give you less than 1% energy loss. Bigger is better if you can afford it because it allows you to upgrade later with more strings and maybe add a combiner box.

 

[Zwy]

True. I should have specified distance plays a role. My runs are less than 100ft

Not just distance, it also is Vmp. Note the Vmp for same length and the difference in voltage drop for the same wire size and amps.

 

[Zwy]

My inverter is an EG4 6000 EX. Two strings of 12 285 w 37v in series solar panels going into one PV input on the inverter

What is your location and how cold does it get there? You need to size strings according to the max VOC of the inverter and the normal operating range. If you are below the max VOC but above the operating range the EG4 SCC will probably not enable charging.

Go here, input your data and see where your string voltage will be at coldest temps for your area. Around here it occasionally hits -30F, maybe every other year so I have take it into account. https://www.midnitesolar.com/sizingTool/

37V, 12S at 0F would be 515VOC. 37V, 12S at -30F is 540VOC