I want to move my Growatt 12KW inverter and batteries to a building closer to my Solar panels. I worry about the batteries burning down the house.... Anyway the Terminals on the Growatt only allow for a 6awg wire for the AC in and out. Debating what type of wire to use to make the run which is going to be over 100' I can get 100amp Aluminum 2-2-2-6 wire cheaper than 6/3 direct bury. Have to make 2 runs, so probably will need 250' which is goin g to be over $1000 for copper. May save $200 with aluminum, but then I would able to goto a higher capacity inverter if I needed to. Would need a disconnect either way. Just wondering if I should just stay away from Aluminum and bite the bullet.
Moving Inverter, 100' run Copper or Aluminum direct bury?
- Thread starter Hotwires
- Start date
OzSolar
Whatever you did, that's what you planned.
A 100 amp disconnect will have terminals rated to allow you to use larger AL on one side and the smaller copper on the other side. Allows for a nice clean and safe way to do it.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
I ran 150 feet of 4/0 aluminum URD from my building where my inverters are to the house transfer switch.
At the building where my Inverters connect I used a Power Distribution block to combine my 2 inverters on one side and the 4/0 AL on the other.
If you are only sending 50 amps probably get away with something cheaper.
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Madco
Solar Enthusiast
Have you thought about 2-2-4 urd aluminum. Its around $2.60/ft. Don't bring it up into any building and seriously consider putting it in conduit.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
URD is direct bury other than when it comes above ground. To go in a building has to be RHH/RHW-2 I believe.
You can run URD to a junction on outside then SER from there inside if the URD isn’t rated for conduit.
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Madco
Solar Enthusiast
I agree URD is direct burial, but over the years I have seen many direct burial cables fail because of nicks in the insulation. This is catastrophic when the conductors are aluminum. Can be damaged when installed, damaged from frost heave of sharp rocks, etc. Not to mention that a lot of folks just don't bury it to the proper depth. I only suggest conduit for those reasons. Even given that PVC conduit isn't "cheap" anymore, it is still cheap insurance.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
Most of the POCOs here use URD from transformer to meter pan without conduit.
My house is URD to the transformer.
Madco
Solar Enthusiast
Sure, it is allowed, I just specify it be in pipe. Just a personal preference.
When you join the aluminum cable to copper do use cu/al rated connectors and anti oxidizing compound such as Ideal Industries No-Alox, then when tightening the connectors wait 10-15 minutes , retighten them. Both Aluminum and Copper will deform in shape when clamping thus reducing clamping pressure.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
That would be expensive I think.
I guess it also depends on where they live.
My URD is almost 3 feet down. Well below frost line here.
Not sure what frost line is for other places.
Nobodybusiness
Collecting the leftovers of the Great Sky Reactor.
You know I didn’t think about this when I was running mine but you could use MHF.
That’s direct burial and you can run it inside in conduit.
OzSolar
Whatever you did, that's what you planned.
When we do a direct bury run we bed the trench with limestone fines or sand (it's what we can get where we are working at the time), run the wire then put at least 2" more inches of fines on top of the the wire then carefully pick out the sharp rocks by hand before we backfill. We still put conduit under any places that might see vehicle traffic. This is typically for ground mount arrays that are 200' or more away from the MDP.
