Most often 400 A service is achieved here by installing two 200A panels. Last time I had a 200 A panel installed (to replace a 60A fuse box) the total charge was about $3000. I could imagine getting to 3-4 X that, but it's not clear how you get to $32K especially if you're going from 300 to 400. The wire and panel boxes don't explain it.

I'd seriously review the need for 400A with the electrician. Unless you're running electrical resistance heating or some opther unusual load, or the house is immense, it seems unlikely.

Why do you need to have the 400 amp panel at the street - that seems really odd?

How far is it from the street to the garage - is this underground or aerial?

How many circuits on the main panel?

Thanks for the insights. Do we even get a choice on 300amp vs 400amp service? The way the electrical engineer made it sound, the calculations were done based on the appliance list for the home. Code requires using 75% of peak capacity in the calc. Ie: assume everything is on at the same time x .75. It’s a 2700 sq ft main house with a 675 sq foot guest apartment. It does have induction in the kitchen, an all electric hvac and EV car charging.

In terms of why put the panel at the street, as I understand it, it’s a very large unit. The side of the guest house has scuppers for water drainage for the roof and the panels would have been to close to the runoff for safety. The other alternative was on the front of the guest house which just seemed ugly even when painted.

I’ve attached a write up of the equipment planned in case that helps.

It looks like the "plans" were changed to add more panels? So it is hard to comment on the costs without seeing them.

But I still don't understand why a 400 amp panel is so much larger than a 300 panel that it cannot fit in a garage.