Essentially, I want to upgrade the electric service to my house from 100A to 200A (or more).
Now for the details:
1) I called my utility company and I was told by them that my meter and service allow up to 320A (which I was told here likely means 80% continuous rating for 400A service).
2) My meter and main breaker are located some distance from the subpanel with individual circuit breakers. As such, I have two boxes with circuit breakers separated by ~100ft of service wire.
4) I have about 100ft of service cable going through conduit to my subpanel, which has the individual circuit breakers. I forgot to check for other wire specs (ex. THW, THWN, etc.), but I saw that it is 4GA wire on the conductor wires.
What I want to do:
1) I want to get 16 slots and ≥200A at my subpanel.
It's actually quite simple.
How I think I can do it:
1) Somehow get a total of four hot wires coming out of the main breaker box and add another 100A 2-pole main breaker to get a total of 200A.
2) Run another set of service entry wires from the additional main breaker through the conduit.
3) Install a second subpanel, identical to the first, to be serviced by this new set of wires I just ran through the conduit.
Questions I have:
1) For step 1, can I add a second main breaker that is connected to the meter through a jumper wire. Essentially, I would be adding a panel like this one (only using that product as a representation of what I intend), or do I need to replace the existing meter/main breaker panel with something like this one?
2) If I have 2 2-pole breakers or 1 4-pole breaker, can I run a new set of conductor wires without having to upgrade the existing ones? The difference is, if I replace the existing ones with 2/0 wires (for 200A), it will cost $1500. If I add new ones (protected by their own breakers on a 4-pole), it will cost $150.
3) Are the existing wires too small, since this website says that 4GA is only suitable between 70A and 95A, depending on the wire temperature rating? I'll be sad if they are too small.
4) Does it make sense to add another subpanel, or would it be better to replace the existing one with a 16+ slot subpanel?
If I am forgetting to ask something important, or if you need more info, please advise.
EDIT: My question was flagged as being similar to this question, which I also posted previously. This is a follow-up that details, more-specifically, a practical renovation project rather than a theoretical question regarding how breakers are built into circuits.
EDIT: Just called my utility again, and they told me something different this time. The current rep had no idea why I was told 320A last time and said they don't keep service ampacity numbers on their end. Instead, I'll just have to put in an application (because I'd be messing with the meter) and a technician will come out to talk through the project and determine what's required.