PV Distance 460'

[dmkjr]

Looking for some recommendations. About to start a decent sized install for a friend. There are several large oak trees on her property which is going to cause some issues for the ground array we are installing. We are looking at 16kw array and the best place to install is roughly 420' away, with a max of 460' if we go the long route to ensure to stay away from other utilities.

The array will roughly be running at 400v and 16 amps or something near that with two (or more) PV's. This will be running to an EG4 18kpv system installed in the garage at her home. What is the best way to get the power from the array to the house? We will be burying conduit for the pathway.

thank you!

 

[rhino]

For conduit I would get a quote for HDPE conduit. That is what I used for several 500ft to 600ft runs. All one continuous run with no breaks to get wires caught on when pulling. You can get it with pull tape already installed. If in the budget would suggest running extra empty conduit for any potential future expansion. I'm having to deal with that now wishing that I installed either larger conduit or an extra one in same trench. Also need to get couplings.

500ft rolls of 8 gauge copper xhhw-2. Using voltage drop calculator shows only 2.67% voltage drop for 500ft at 400V 16A using that.

 

[DIYrich]

Maybe a box every 100 feet or so, just in case. Run a separate conduit for low voltage dc and internet. You may want it at the site.

 

[zanydroid]

For What areas are you looking for feedback?

Based on the provided details and without further direction, all I can think of is punch these parameters into a voltage drop calculator with #10 (standard issue, default wire gauge to try) and it looked OK

 

[zanydroid]

Ok sounds like it might be a question for design and installation methods.

What do people think about running an extra conduit or direct bury cable for line voltage? Just in case since a big trench is already being dug and it’s probably easier to achieve the necessary separation of AC from DC solar via separate conduit

 

[pvgirl]

Buried conduit is going to be the best option. Having the inverter at the house, and running the PV high voltage DC back is going to be the best option.

If you have multiple pv stings in a single conduit you will need do the calculations for derating to make sure you don't need to upsize any conductors, the upsizing of the conductors for voltage drop may take care of this but you will need to make sure. Also if you have move then 360 degrees of total bends in a conduit run you will need to provide a pull box, or hand hole. If you use HDPE or schedule 40 PVC conduit you will need to transition to a different type of conduit above ground such as schedule 80 PVC or RMC. Also don't forget the ground to run with the PV circuits to the ground mount arrays.

 

[rhino]

If you have multiple pv stings in a single conduit you will need do the calculations for derating to make sure you don't need to upsize any conductors,

Is there a calculator to do this for you?

 

[Mark-]

If you use HDPE or schedule 40 PVC conduit you will need to transition to a different type of conduit above ground such as schedule 80 PVC or RMC. Also don't forget the ground to run with the PV circuits to the ground mount arrays.

In bold, why?

 

[dmkjr]

Is there a calculator to do this for you?

There is. I had done the calculations but never actually performed a run that long. Just checking on anything the more seasoned people could elaborate on. 2% voltage drop, I'm good with that. We are going to be running a decent sized array at that site.

 

[pvgirl]

In bold, why?

PVC schedule 40 conduit is not allowed to be installed where subject to physical damage, which is generally going to be location where the conduit is running above ground. Now there may be certain cases where other factors exist and the conduit is protected from damage and the install above ground would be ok,

 

[SilverbackMP]

What do people think about running an extra conduit or direct bury cable for line voltage? Just in case since a big trench is already being dug and it’s probably easier to achieve the necessary separation of AC from DC solar via separate conduit

I think it’s a damned good idea. So much so, I did it as well (280 feet mix of schedule 40 and 80).

 

[ncsolarelectric]

Use Polaris Terminals to step up the wire gauge from #10 to #6, then at the other end, repeat the process to step back down to #10. Use a watertight JB at each end of the run. Don't let the voltage drop exceed 2% at most. For the cable in between. you can eliminate the conduit by using direct burial TC-ER Tray Cable.

 

[Supervstech]

460' of cable is going to be a hard pull.
The lighter the cable the easier a time it will be.
Avoid using tape on the cables when attaching to the pull string/rope.
Use as large a conduit as you can afford.
Consider a pulling rig, or using a winch to pull that far.
Friction builds up quickly over 200 feet...

 

[Balrog006]

460' of cable is going to be a hard pull.
The lighter the cable the easier a time it will be.
Avoid using tape on the cables when attaching to the pull string/rope.
Use as large a conduit as you can afford.
Consider a pulling rig, or using a winch to pull that far.
Friction builds up quickly over 200 feet...

Use cable/conduit lube as well. There are gels, foams etc. just get one and use it liberally.