I have an 8 yr old house with what looks like a 200 amp main panel outside my garage. There is a subpanel inside the house that also looks like a 200 amp panel. I want to build a shop 50 yards away that will include a welder, air compressor, lighting and lots of outlets around the 40x60 shop. I don't see any spaces in the main panel to branch off to the shop subpanel.
What are my options? Get a bigger main panel with more slots?
This house requires a Load Calculation to determine its electrical capacity and whether it has already been overloaded, which I feel like maybe it has. I mean this house has 60 circuits already! That's a big house. I'm really surprised to see #1 so many circuits and #2 the 30 circuits in the outdoor panel having not a single AFCI among them. Maybe they pulled the permit under NEC 2011.
The best Load Calc worksheet I've seen (in terms of conforming to NEC) is here, note line 2 is kitchen, dining and pantry general-use receptacles only, circuits you might plug in a coffee maker - not ones assigned to fixed-in-place appliances.
I'm also not liking how previously, the "laundry subpanel" was fed off a <=125A breaker with <=125A wire, and then some epsilon minus decided to bypass that breaker and hotshot it right off the main breaker.
Honestly, this house seems like a great candidate for a 400A service....... or alternately, a "load diet" but I don't see the usual low-hanging fruit (electric dryer and water heater). Maybe the pool heater could be heat-pump-ified?
At first blush, I would recommend a 400A "Ranch Panel" mounted next to this one, with the breaker with mini-panel feeding the laundry panel, and the solitary breaker feeding this now-retired all-in-one. Easy peasy, no circuits to move, 8 more breaker spaces in the 200A side with more capacity.
However, I also see this is a luxury house (beware reverse Dunning-Kruger here; the highest quartile also don't realize it). And a luxury homeowner is going to be at the front of the line for emerging solar/battery/V2X technology.
That technology is much more practical to apply to a 200A service/home than to a 400A. So the ideal arrangement is to split your loads into "critical loads we contemplate ever running on battery backup", versus "non-critical loads that are large and impracticable to have on battery, and we're hunky dory with them being broken until utility power returns". This is now a bigger project - it may still employ one of those Ranch Panels, but the downstream loads would be arranged in a different way, into two panels and subs off those two obviously. The solar needs to be on the "backed up" side so the battery kit can use it to replenish the battery.
The vital part of a battery/V2X arrangement is the MID or isolation switch. It must sit in between the utility supply and the backed up loads. One concept here is that a 400a upgrade will leave you with that original "All-In-One" panel with an empty meter socket. Some 200A MIDs come in a "meter collar" format that would snap right into that meter socket, so you could up-cycle the old All-In-One as your critical loads master panel.
So I'm sorry to explode your scope of work LOL, but as you say, a lot of rearrangement does need to happen for your shop, so NOW is the time to be laying plans for battery/V2X.
By the way, don't worry about EV charging. Tech is readily available (by which I mean half sold at CostCo the other half $300) to squeeze EV charging into any service.
