wpns
Solar Joules are catch and release
I'm moving my 25KVA grid transformer about 100 feet to be closer to the free-standing garage (boathouse) where my solar equipment is (and my batteries will be RSN). This will require adding about 200 feet of mains cable to get the new feed down to where the transformer/meter was to splice into the existing feed to the house.
When I build the house 20-ish years ago, I specified 200-amp service (3/0 wire from transformer to house), but it turns out (see 25KVA transformer above) that 100A service would be fine. I've measured the peak house load at 19.9KW (83A), and copper wire prices are insane, so I'd like to reduce the cost of the additional mains cable (and maybe the breakers) as much as possible/practical/reasonable.
www.encorewire.com
says anything 3AWG or larger has the ampacity, and
says that:
1AWG from the Boathouse to the old transformer location aka "Meter" (200ft) at 100A will drop 2.7%
3/0 from old transformer location to house (250ft) at 100A is another 1.9%
so my total voltage drop is under the 5% recommendation in the voltage drop calculation above.
Once all is said and done there'll be two EG4 18Kpv inverters in parallel in the Boathouse, which are good for 50A each, and I'm planning an AC Combiner with 60A(?) inverter breakers and 125A(?) output to the house.
Does that make sense? How do I select breaker sizes for AC panels and combiners to be reasonable in terms of engineering, and ideally meet code?
If I have a 400A breaker at the house, but a 125A breaker at the Boathouse feeding the house, I don't need to replace the main breaker at the house, do I?
I'm having a hard time wrapping my brain around all the possibilities, and before I saw the wire prices (and realized the 25KVA transformer wasn't going to provide any more than 100A service), I had 3/0 wire everywhere and 200A breakers everywhere, but now I'm realizing that's just overkill...
Thanks!
When I build the house 20-ish years ago, I specified 200-amp service (3/0 wire from transformer to house), but it turns out (see 25KVA transformer above) that 100A service would be fine. I've measured the peak house load at 19.9KW (83A), and copper wire prices are insane, so I'd like to reduce the cost of the additional mains cable (and maybe the breakers) as much as possible/practical/reasonable.
Encore Wire Corporation
At Encore Wire, we always put our customers first. We continue to look toward the future of our planet, at our resources, our products and our capabilities to determine how we can bring more value to you.
says that:
1AWG from the Boathouse to the old transformer location aka "Meter" (200ft) at 100A will drop 2.7%
3/0 from old transformer location to house (250ft) at 100A is another 1.9%
so my total voltage drop is under the 5% recommendation in the voltage drop calculation above.
Once all is said and done there'll be two EG4 18Kpv inverters in parallel in the Boathouse, which are good for 50A each, and I'm planning an AC Combiner with 60A(?) inverter breakers and 125A(?) output to the house.
Does that make sense? How do I select breaker sizes for AC panels and combiners to be reasonable in terms of engineering, and ideally meet code?
If I have a 400A breaker at the house, but a 125A breaker at the Boathouse feeding the house, I don't need to replace the main breaker at the house, do I?
I'm having a hard time wrapping my brain around all the possibilities, and before I saw the wire prices (and realized the 25KVA transformer wasn't going to provide any more than 100A service), I had 3/0 wire everywhere and 200A breakers everywhere, but now I'm realizing that's just overkill...
Thanks!
