600ft distance from open field to meter/panel

[MisterSandals]

I can see some wrong answers already about wire size (10 ga won't cut it), 600' is a long way,

Are you contesting the voltage drop calculator? Its not mine so please bang away at it with your own info that you have. I'm all for being corrected and learning but simply saying something is wrong is not very helpful.

 

[OzSolar]

It's not a nickname. It's the actual description of the conductors. The numbers tell how many and what size they are.
Vassar is just one of the manufacturers.

Vassar is not a manufacturer. Omni Cable, South Wire and Nassau are examples of numerous manufacturers of triplex and quadraplex.

"Vassar" really is the common nickname or trade name which refers to 4-4-4 which we both agree on. 6-6-6 would be called "Erskine" regardless of manufacturer and so on. Maybe I could have used trade name instead of nickname but whatever you call it, it's not the manufacturer.

Another example is "Sweetbriar" which is the trade name for 4/0-4/0-2/0 triplex URD regardless of manufacturer.

Yes copper is hard to come by and carries a price premium even if you can go with lower gauge wire.

FWIW, once you get away from the commodity stuff like Romex and the smaller THHN my local supply houses always have much better pricing on wire than the internet or the big box stores. Some will sell to walk-ins without an account in case you haven't checked those routes out already.

 

[worldwander]

Vassar is not a manufacturer. Omni Cable, South Wire and Nassau are examples of numerous manufacturers of triplex and quadraplex.

"Vassar" really is the common nickname or trade name which refers to 4-4-4 which we both agree on. 6-6-6 would be called "Erskine" regardless of manufacturer and so on. Maybe I could have used trade name instead of nickname but whatever you call it, it's not the manufacturer.

Another example is "Sweetbriar" which is the trade name for 4/0-4/0-2/0 triplex URD regardless of manufacturer.


FWIW, once you get away from the commodity stuff like Romex and the smaller THHN my local supply houses always have much better pricing on wire than the internet or the big box stores. Some will sell to walk-ins without an account in case you haven't checked those routes out already.

My experience over the last year has been the supply houses in Florida carrier a 30% premium price on everything electrical compared to Lowes and Home Depot. In particular local supply houses are usually out of everything. The best pricing by far that I can find on bulk low gauge wire is at https://nassaunationalcable.com/.

 

[worldwander]

Are you contesting the voltage drop calculator? Its not mine so please bang away at it with your own info that you have. I'm all for being corrected and learning but simply saying something is wrong is not very helpful.

The difference is aluminum vs copper in that 10 awg is correct for copper. Posted details on aluminum vs copper related to price per ft. https://www.southwire.com/calculator-vdrop

 

[MisterSandals]

The difference is aluminum vs copper in that 10 awg is correct for copper. Posted details on aluminum vs copper related to price per ft. https://www.southwire.com/calculator-vdrop

My example, as shown, specified copper. Using your calculator i got 2.22% voltage drop.

I'd still like to see what was wrong with 10AWG.

If someone says something is wrong, i don't think its out of line to ask why.

 

[DThames]

My example, as shown, specified copper. Using your calculator i got 2.22% voltage drop.

I'd still like to see what was wrong with 10AWG.

If someone says something is wrong, i don't think its out of line to ask why.

10ga vote yes. Most don't understand voltage drop on solar PV. It is largely irreverent compared to the worries with voltage drop on an AC system. A solar PV system is a "soft" power supply and series resistance added to it is often not that bad overall. Copper THHN in conduit would be wise. Not sure why the some think larger than #10 copper is needed. Again see what Sol-Ark says about copper sizing for 600ft.

Edit Nassau is showing $320 per 1000 feet. Get a quote, maybe get a better price.

 

[OzSolar]

My experience over the last year has been the supply houses in Florida carrier a 30% premium price on everything electrical compared to Lowes and Home Depot. In particular local supply houses are usually out of everything. The best pricing by far that I can find on bulk low gauge wire is at https://nassaunationalcable.com/.

That's too bad. I just checked and last week we paid about 30% less for 2-2-2-4 quadplex delivered to our jobsite the morning after we ordered it from a local supply house.

 

[worldwander]

10ga vote yes. Most don't understand voltage drop on solar PV. It is largely irreverent compared to the worries with voltage drop on an AC system. A solar PV system is a "soft" power supply and series resistance added to it is often not that bad overall. Copper THHN in conduit would be wise. Not sure why the some think larger than #10 copper is needed. Again see what Sol-Ark says about copper sizing for 600ft.

Edit Nassau is showing $320 per 1000 feet. Get a quote, maybe get a better price.

Need direct burial to avoid cost of conduit

 

[Mike 134]

Are you contesting the voltage drop calculator? Its not mine so please bang away at it with your own info that you have. I'm all for being corrected and learning but simply saying something is wrong is not very helpful.

Using the Op's number of 10amps from option B of his post 1 empirical knowledge tells me 10Ga is not large enough for a 600' 10 amp run.

Now if you choose to plug-in your own lesser number of amps then at some point it becomes adequate.

 

[Zoomyn]

Did I see mention of maximum DC current for wire design spec is X 1.25??

A 125% factor accounts for under certain conditions irradiance/temperature lower than STC, the effective short circuit current may be higher….

 

[lotsofyoda]

Looking for feedback on a solar install where the place we need the power is 600ft from an open field in the woods surrounded by tall trees.

Have a remote property that we purchased, and the bunkhouse is in the woods and to get to the open field is a 600ft run. The utility ran underground power 400+ ft from the transformer to the meter with a 200 amp panel breaker/service(20+ years ago). In July(Florida location) the peak hour was 13KWh, so assume a 50 amp average indicating AC on in the house and the workshop.

Planning an expansion of larger building out to the "open field area", so long term that will become the primary driver of power. Would like to centralize solar and SOL-ARK 15K, batteries, generators out in the field given that SOL-ARK can expand capacity by adding additional units.

When I did the voltage drop calculator from Southwire can't do a wire big enough for a 600ft run at 240V and 200 amps. Even at 240V and 100 amps would require a 600KCMIL cable which is direct burial and very expensive at $18 a foot for 750-750-500. Going with a 240-480 to 480-240 voltage 50KVA transformer from Maddox is $2200 each for $4400 then allows for 4/0 cable($6 a foot). This solves the getting power to the existing panel at a cost of $8000. To add in the ability to net meter and run off the grid would need to add an additional appropriately rated cable to bring power from the meter 600ft to the SOL-ARK unit trying to centralize in the field. Assuming SOL-ARK 15K, when running off of the grid doesn't do a AC-DC transform and then back to AC for the load, so if the meter is the primary source of voltage, it is already 400ft to the meter from the utility company transformer plus 600ft to the solar hut and then 600ft back to the main panel. Not good.

Option B is to put SOL-ARK and batteries at the existing panel/meter location and run high voltage DC from 10KW of panels over three strings to the SOL-ARK DC input. for 10 panels per string 43V per panel at 10 amps = 430V. Running three strings 600 ft of 4-4-4 wire is $2000 in wire costs. Saving $6000 and in theory, a more optimal interface to the grid.

As we add buildings out in the field(farming related) would not be able to leverage existing solar/AC/grid infrastructure. With net metering, any excess solar beyond topping off the batteries can go back as a credit and in theory could use that as a virtual meter credit if we end up adding another meter out in the field. Not really worried about net metering, but don't want to do anything that prevents it if the future is going to bring KWh rates 2X and 3X what we have today.

Has anyone found a reasonable price 50KVA 240-480V transformer for less than $2000? Ideally would like to do 240-600 if the wire for direct burial is rated for 600V but haven't found that option. The best options I could find was at maddoxtransformer.com

Any good options for wire? The prices are coming down but still a major cost. The best price bulk cable I can find and includes free delivery is at https://nassaunationalcable.com/collections/clearance-sale

Has anyone gone the high voltage DC route for 10KW of solar over 500+ ft and had issues/problems?

I have my panels 250 feet from my inverters. 6 solar arrays to 6 inverters = 12 wires. 10AWG. Runs at 320V 20 amp DC.
So, same idea, separate your panels from the inverters and run DC at high voltage. Some inverters will go as high as 550V (maybe higher) as PV input.

 

[rcrracer]

Two sets of batteries? Use one while charging the other. A third world town did this. Two semi trailers full of batteries, alternately charged at the nearest town with electricity. It was too expensive running AC.

They may still make something like AL USE used for mobile homes. Four direct burial wires twisted together.

 

[timselectric]

"Vassar" really is the common nickname or trade name which refers to 4-4-4 which we both agree on. 6-6-6 would be called "Erskine" regardless of manufacturer and so on.

I see.
I've never heard those nicknames used in my neck of the woods. We just go by the numerical denominations around here. But I try to learn something new, every day. Maybe it will come up in a future conversation.

 

[MisterSandals]

Using the Op's number of 10amps from option B of his post 1 empirical knowledge tells me 10Ga is not large enough for a 600' 10 amp run.

Now if you choose to plug-in your own lesser number of amps then at some point it becomes adequate.

I was not using my numbers. What was originally specified was 10kW, 10 panels and 430V. This works out to 7.75A.
After my post, it morphed to 9 panels and 10A. No mention of what else changed but putting in 10A, the calculator shows 2.87% voltage drop.

Is this too high for this use case? I'm not arguing, just trying to learn something.

 

[DThames]

I was not using my numbers. What was originally specified was 10kW, 10 panels and 430V. This works out to 7.75A.
After my post, it morphed to 9 panels and 10A. No mention of what else changed but putting in 10A, the calculator shows 2.87% voltage drop.

Is this too high for this use case? I'm not arguing, just trying to learn something.

View attachment 123571

Agreeing with MisterSandels that this is fine, this drop (calculation) is not very significant in an MPPT PV DC environment.
1. The voltage drop will not likely take the voltage below the MPPT input range, so things will work just fine.
2. Because rated peak amps doesn't happen very often nor for very long, the daily power loss due to resistance is not nearly as much as calculations at peak rating amps would show.

The OP stated that he was trying to avoid conduit cost. Direct bury might not cost as much overall but you certainly will have larger costs if there is a need to grow the system at a later date. If the conduit was in place and had space for another run (good planning) wire cost would be all that is needed to get the additional power to the target site.

 

[Zwy]

Has anyone gone the high voltage DC route for 10KW of solar over 500+ ft and had issues/problems?

I have 420 feet. I had purchased 2 LV6548's long before the EG4 6500EX came out and planned PV at 120 feet away originally. Changed plans and moved PV to the 420 feet.

Decided to buy 2 EG4 6500EX's after looking at wire cost using the 250V limit on the LV6548's. Would have required 8AWG and twice the number of wires due to the voltage limit. Going with the EG4, 10AWG and 1/2 the number of wires. Would have cost $2500 for the 8AWG, cost me under $700 for the 10AWG.

The trick is high voltage, low amps. Panel choices play into this, find a combination that allows highest wattage close to the SCC rating with high voltage and low amps. For the EG4, I have 530W panels with a VOC of 49.5V. Eight panels in series and even though it gets to -30F here, I'm still good with the VOC running it thru the Midnite calculator.

If the inverter you are choosing doesn't have a higher input voltage, you can always just use individual SCC's rated for higher PV voltages.

 

[OzSolar]

Did I see mention of maximum DC current for wire design spec is X 1.25??

A 125% factor accounts for under certain conditions irradiance/temperature lower than STC, the effective short circuit current may be higher….

Isc x 1.56 to meet NEC. 1.25 for continuous operation (3hrs) plus 1.25 for temperature derate. Once you do that you will never run into a problem exceeding 3% voltage drop at NOCT. Don't believe me? Just plug it in and see for yourself. Don't use the STC ratings when sizing wire for voltage drop, it's useless to do so.

But I try to learn something new, every day. Maybe it will come up in a future conversation.

Maybe it will! My days are much better when I'm eager to learn to new things.

 

[629658]

My example, as shown, specified copper. Using your calculator i got 2.22% voltage drop.

I'd still like to see what was wrong with 10AWG.

If someone says something is wrong, i don't think its out of line to ask why.

I used the Sol Ark string calculator. My panels are 350’ from the inverter. According to their calculations I needed 3 pair of #8 for an acceptable voltage drop. So that’s what we did.

 

[MisterSandals]

I used the Sol Ark string calculator. My panels are 350’ from the inverter. According to their calculations I needed 3 pair of #8 for an acceptable voltage drop. So that’s what we did.

What are the volts and amps of your system?

 

[629658]

What are the volts and amps of your system?

I’d have to go pull my sheets to be accurate but off the top of my head around 300v and 13-15 amps. I have a 44 300w array. I split them up into 2 strings of 18 and one string of 8.