I am not 100% sure, but my electrical breaker panel, main breaker, is "quad" looking with each of the smaller parts saying 200A, but there is one bar across them. similar to this breaker:
Find the 200 amp Quadplex Type QPP Circuit Breaker Q2200B, 200 amp designed to protect your home wiring from high temperatures caused by excess electrical current at The Home Depot
www.homedepot.com
I assume it means my house also has 200A service. My outside electric company meter also says "CL200" among other markings on it.
So, that settles it, that you have a 200 amp service. So that means your best and most economical route is 20 solar panels with an output of 7.6 KW max.
Here are you other options.
1). Increase your electrical circuit current capability. That requires new panels at a minimum, and like I would have had to, you may well have to have your utility increase your electrical service power. In my case that would have required replacing the transformer that supplies the four houses on the circle.
My solar contractor was keen on increasing my electrical service with new panels. Actually that would not have been worth it. Luckily I ran it by Dakota Electric and found out that this was not a practical option.
2). Batteries for the excess power. This is not a good option and does not justify the expense in my view.
The reason becomes the i-squared power loss. Let me explain.
As you lower voltage current goes up by a reciprocal amount. However the power loss goes up by the square of the current. That is the physics of it.
Now to reduce those losses each panel has an inverter. Mine are 20% efficient which is the SOTA currently.
So the phase locked loop in the combiner synchronizes all the inverters with the AC mains from the power company. The panels output at 240 volts peak to peak +/-, like the US house supply. To keep the load even. Every other breaker is wired to the opposite phase at the panel to keep the load reasonable even between the 120 volt phases. 240 volt appliances are full phase at 240 volts.
So in order to use a cable down from the roof that is not like car battery cable the inverters output 240 volts AC.
Now if you have batteries then in addition to the 20% loss on the roof, you have another 20% loss converting it back to DC to charge the batteries, and then another 20% loss when you convert the DC from the batteries back to 240 volts AC. So you have three 20% losses instead of one. A very bad plan in my view. Now people try and sell this, but it is a bad idea. Round here code requires the batteries be in a structure not connected to the house, which in my view is sensible. So that makes 2 way metering by far the best option.
Now, the solar people will try and cover your roof with all the panels they can get on it.
However, I spoke with the chief electrical inspector for MN and the local inspector for Eagan/Mendota Heights. The latter was a really nice guy and very experienced and reviewed the whole situation with me. That saved me huge mistakes.
These solar companies will not explain the NEC rules. Mine did and included new panels, but that made the cost prohibitive and Dakota Electric explained that solution was wide of the mark.
So then I got a plan submitted that met all Federal NEC codes and local codes.
Now, my company was pretty cooperative once they realized I know the regs backwards and forwards. They actually I think, got a little scared of me. From then on out I only dealt with their most senior engineers and we got into a really good working relationship right away.
So plans were sent to an fro and we came up with the optimal plan. Note avoid dealing with marketer and MBA types. As you know I have visceral loathing of those types and can spot them a mile off.
My case was complicated by the fact with an ICF home the combiner, fireman's switch and reverse meter can not be mounted on the house.
So I had to design that free standing structure and have a concrete foundation laid for it, with it mounted to code. I designed it, and built it with my son in law in three hours. I previously mounted the L-anchors while the concrete contractor was here, and the concrete still liquid and wet. I had to be really precise in my measurements as there was no redo. I had to pay attention to the equipment spacing according to NEC and issues like that. How the above three devices are mounted is in the codes.
Anyhow it is a very strong design and won't go anywhere.
All the planning paid off, and it passed electrical, Dakota Electric inspections and building inspections first time with zero issues or queries. From what I have been told this is highly unusual round here.
So, it has been up and running for 8 months now with no issues, and produced 8.6 mega watts to date.
So I think we are on track to meet the design criterion to replace 65 to 70% of our annual electricity consumption.
The cost was $42,000 before the tax rebate. So, this is going to cash flow, and will for you if you get it up and running by the end of the year.
This installation is now in the Enphase engineers teaching file, in particular in how to install solar on an ICF home, which they had not done before.
I am really pleased with the Enphase equipment and their software support for system monitoring.
Be careful, the inspectors warned me that there are sharks and bad practice out there all over the place.
The local inspector told me that it was highly unusual to pass a solar installation first time round here.
If you have further questions ask. Now is the time to get you system right, and don't expect to get the correct information from the vendor first time. I did not, and I advise you to make sure they know you ARE IN CHARGE. Like i did, you might have to let them know that right up front. You can only do that if you know what you are doing.
I strongly recommend you run your design by your local electrical inspector before signing the final design. Horror stories abound in this area, according to the inspectors I spoke to.
So don't let your contractor do something you feel is not right. If you are not sure talk to your local electrical inspector. Don't be afraid to be a PITA, one of my specialties. I shut the project down twice as I knew practices were not optimal. Third time they followed my master plan. So make sure your project is right by design.
If you want standby power then and free standing auto start generator is by far your best option, over and above your solar installation. I have to have that for medical reasons.
