Best way to run AC power 500 ft from array to cabin

[AlaskanNoob]

But you still have to schlep the gas up the hill, no?

Once we drive the gas to the end of a dirt road, we have to then transload it to our ATV. Then drive the tracked ATV two miles and a thousand feet up to our homestead. I'll make a trailer with an external fuel tank that I can switch from truck to ATV and that will be our external fuel supply for the generator.

Nothing is easy in Alaska except going bankrupt and freezing to death.

 

[John Frum]

Also gasoline does not store well.
Since the honda generator is fuel injected it will probably fair better but still don't forget the stabil.
I know its strictly off topic but I think it relevant.

 

[AlaskanNoob]

OK I'm out. Good luck.
I am sorry our advice and comment's are not what you actually want to hear.

Me directing YOU to a thread that's more on topic for YOUR input and inviting you to share your information there instead of in this thread dedicated to running AC power 500 feet does not equate to me not wanting to hear the advice of you and others.

Take care.

 

[AlaskanNoob]

Also gasoline does not store well.
Since the honda generator is fuel injected it will probably fair better but still don't forget the stabil.
I know its strictly off topic but I think it relevant.

It's related to running AC power since it will be AC power coming from the generator into the system. Yes, we will have to keep an eye on the fuel life.

 

[Ozark Tinkering]

Nothing says you can't run your own overhead power line except aesthetics. Step it up to 480 at the array and back down at the cabin or run it in dc, run overhead aluminum 4plex wire. Check out the code and see the difference between current carrying capacity of wire buried in conduit vs. wire in free air. Just maintain the legal overhead clearances

 

[AlaskanNoob]

Nothing says you can't run your own overhead power line except aesthetics. Step it up to 480 at the array and back down at the cabin or run it in dc, run overhead aluminum 4plex wire. Check out the code and see the difference between current carrying capacity of wire buried in conduit vs. wire in free air. Just maintain the legal overhead clearances

I've got to dig the trench for the GSHP horizontal loop anyway so I think burying the wire would be better for us especially given all our trees falling over all the time. We carry an electric chainsaw in our ATV because between the wind and frequent earthquakes, we have trees blocking our ATV trail all the time. We could *maybe* save money on wire by going overhead if it didn't have to be direct burial wire, but I don't think it would work in our application. Appreciate the suggestion though.

 

[Ozark Tinkering]

What was the calculated load per leg of your ac power going to be?

 

[John Frum]

Nothing says you can't run your own overhead power line except aesthetics. Step it up to 480 at the array and back down at the cabin or run it in dc, run overhead aluminum 4plex wire. Check out the code and see the difference between current carrying capacity of wire buried in conduit vs. wire in free air. Just maintain the legal overhead clearances

I don't think its established that they are using conduit.
Also there was talk that the trench depth would be below the frostline which would probably mean a year round temperature of less than 60F.

 

[WYtreasure]

I've got to dig the trench for the GSHP horizontal loop anyway so I think burying the wire would be better for us especially given all our trees falling over all the time. We carry an electric chainsaw in our ATV because between the wind and frequent earthquakes, we have trees blocking our ATV trail all the time. We could *maybe* save money on wire by going overhead if it didn't have to be direct burial wire, but I don't think it would work in our application. Appreciate the suggestion though.

There goes my solar clothes dryer suggestion, no power pole, no clothes line.

 

[AlaskanNoob]

What was the calculated load per leg of your ac power going to be?

I think @MrsAlaskanNoob came up with a total load to the cabin of about 15KW when trying to future proof it. I'm not sure what that equates to per leg.

 

[AlaskanNoob]

I don't think its established that they are using conduit.
Also there was talk that the trench depth would be below the frostline which would probably mean a year round temperature of less than 60F.

Correct. We're not sure if we would use conduit ten feet down, or just direct burial wire.

From the calcs we've done for our location, extrapolating from old charts from other locations in the state, we think the temp at ten feet down is likely to be between 37F-50F throughout the year. But to complicate that more, we're planning on running our GSHP horizontal loop in the same trench for that 500 feet (then the loop will branch out for more loop on the south facing slope that the PV will be on).

The use of the GSHP over time could bring those temps down over the winter as it sucks the heat from the soil. We'll oversize the loop on the south facing slope to try to minimize that and we're contemplating installing an independent loop in the south facing slope hooked up to *something* that will utilize the solar dump load in the summer to re-charge the soil in the summer with heat.

 

[WYtreasure]

Correct. We're not sure if we would use conduit ten feet down, or just direct burial wire.

From the calcs we've done for our location, extrapolating from old charts from other locations in the state, we think the temp at ten feet down is likely to be between 37F-50F throughout the year. But to complicate that more, we're planning on running our GSHP horizontal loop in the same trench for that 500 feet (then the loop will branch out for more loop on the south facing slope that the PV will be on).

The use of the GSHP over time could bring those temps down over the winter as it sucks the heat from the soil. We'll oversize the loop on the south facing slope to try to minimize that and we're contemplating installing an independent loop in the south facing slope hooked up to *something* that will utilize the solar dump load in the summer to re-charge the soil in the summer with heat.

Maybe zig-zag that wire within the trench a bit to allow for the ground moving so much. Perhaps 525 feet of wire is needed.
If you enjoy looking at soil in the trench, you may be able to see the faults.

 

[John Frum]

Another thing about conduit.
I don't think its feasible to pull wire through a conduit on a nylon draw string.
Pulling a 12 awg wire through a 520 foot conduit with 2 90 degree bends that already has multiple wires in it sounds like a pita?

Also I vaguely remember seeing a video that says you should have some verticle separation to mark different items in the trench.
I also remember that each item gets a descriptive warning tape which has some separation as well.

 

[Ozark Tinkering]

Another thing about conduit.
I don't think its feasible to pull wire through a conduit on a nylon draw string.
Pulling a 12 awg wire through a 520 foot conduit with 2 90 degree bends that already has multiple wires in it sounds like a pita?
I vaguely remember seeing a video that says you should have some verticle separation to mark different items in the trench.
I also remember that each item gets a descriptive warning tape which has some separation as well.

I've pulled literally 100s of miles of wire with a nylon string. The biggest mistake DIYers make when installing underground conduit is they don't use steel 90ºs and 45ºs when they install the conduit run. Then when they go to pull the string it actually cuts into the wall of the conduit and creates lots of friction, even using lubricant. If your conduit is properly sized and you use steel for any hard turns in the trench you should not have any trouble. If it's anything larger than a #12 for that distance, blow/suck a small line tied to a plastic bag with a vacuum and then use that small line to pull in a 1/4" nylon rope. Then use the 1/4" rope to make the pull.

 

[John Frum]

The biggest mistake DIYers make when installing underground conduit is they don't use steel 90ºs and 45ºs when they install the conduit run.

Can steel conduit be used as the grounding conductor?
I'm guessing the conduit is expensive and labour intensive in and of itself.

If it's anything larger than a #12 for that distance, blow/suck a small line tied to a plastic bag with a vacuum and then use that small line to pull in a 1/4" nylon rope. Then use the 1/4" rope to make the pull.

Can you add a wire after the initial pull?

 

[Ozark Tinkering]

The steel conduit in the ditch is not bonded in any way. It's buried in the ditch. If you used steel to come up out of the ditch into your panel it would need to be bonded to ground. Underground service risers run in pvc need to be schedule 80.

 

[offgriddave]

Hello DIY Solar folks,

If the solar array is 500 feet from the house, and we choose to place the inverter at the solar array, how can we best do that in a way that avoids (or mitigates) a crazy expensive wire cost? Details about constraints and design follow.

Two inverters. One at the panels and one at the house. The one at the panels would be the batteryless Growatt ES either 3500 or 5000 ES.

10 or 8 awg wire 500ft to the cabin. At 220v or 240v. Only 300-600 watts.

At the cabin, a battery charger. Set at 300 or 600 watts.

That would charge the battery to the second inverter. The second inverter would power your house.

...And you are only going to get 2000-3000 watt hours a day. Which is why everyone is pointing out to change your power usage.
If you want to upgrade this, you'll have to put some batteries up at the panels.

The following items are un-changeble constraints (because of reality on the ground/things we've already bought):

2. Distance from array to cabin is 500 feet. Can't be helped.

5. At the cabin, overall demand assuming a bunch of things on at one time is maybe about 15.2kw (heat pump and water heater are largest components of this). We need at least one 240v circuit for the ground source heat pump (3kw demand) and another one for associated water heater (1.6kw demand from the heat pump and 4.5kw max demand for aux heat). Possibly a third 240v circuit for an appliance (e.g., combined/washer dryer) (say 2kw demand). If I had my druthers, there'd also be an oven (also 240v, 2.5kw) but the reality is we're probably getting beyond what we could do, and likely wouldn't be using these things at same time (save for the heat pump/water heater). In future, possibly a fourth 240v circuit for charging electric ATVs. Everything else on 110/120v.

Heat pump, water heater, washer, dryer (???? that's a wtf), oven?
You will have to forget about all of that in DIY world. Every single one. Not going to happen. Even if your panels were right next to the cabin. Unless you have an unlimited budget and an EE degree. Even then it would be a waste.

You'll just have to figure out how to get propane up the hill on snowmobiles or what have you.
Nobody in Alaska takes showers anyway

 

[Ozark Tinkering]

Can steel conduit be used as the grounding conductor?
I'm guessing the conduit is expensive and labour intensive in and of itself.

Can you add a wire after the initial pull?

If you think there's a possibility you will need to pull another wire later, when you make the initial pull just attach a rope along with your wire and pull it along. That'll give you a way to pull more later ...if you have capacity left in the conduit.

 

[Ozark Tinkering]

10 or 8 awg wire 500ft to the cabin. At 220v or 240v. Only 300-600 watts.

Didn't we establish this is a 15kw system?...yer about 14.5kw short of a load.

 

[noenegdod]

Are you confusing forum and the topic of a thread? It is an interesting topic for me as I contemplate adding DIY solar to a barn.

I think it is an interesting topic as well but the OP cannot lose sight of where he is and the focus of the community. People are seeing flaws in the approach and voicing them and giving alternatives. From that part of the conversation you may learn as well but he wants to shut that down because he has blinders on.

If someone started a thread called "best way to take strychnine" I would assume most people would recommend not doing it and fail to keep the thread "on topic"

Im not going to reply any further as it is pointless but the counter point is always just as valuable as the pro point.