I am looking for advice from people who know their electric service. I am NOT seeking "legal" or "permit" or "what happens if you don't follow protocol" advice. I'll take care of all of that locally. What I'm seeking is the physical practicality of using *what I have* which I will explain in detail, with a new Model 3 that will draw a continuous 40A.
How my house is laid out now:
~~ Underground service of 200A or more capable (confirmed with utility)
~~ METER rated for 200A (confirmed with utility)
~~ On the (right) side of the house, where the utility comes in, and where the meter is, we have our MAIN. We have confirmed that the cables coming off the METER and connected to the MAIN (about 2 feet or less of cable) is NOT 200A cable. It's rated for 100A and has a 100A MAIN breaker on it.
~~ The cable that runs from the MAIN BREAKER, up the wall on the right side of the house... through two attics somehow... and down into the garage into the panel (on the left side of the house) is 100A rated as well.
The panel itself is maxed out on physical space. And the panel will not accomodate "twins" so we cannot double-up any of the existing breakers. My local electrician friend believes that, if we were to swap out the panel itself, giving us more space... then add a 16-50 NEMA 240V... that I'm still never going to come close to the 100A level. And we have done several AMP-CLAMP tests, and with central air on, a window air unit in a bedroom, all lights, tvs, tv gear, computers, 2 fridges, and a handful of other stuff... I got one leg of my panel to 22A and the other to 31A. I realize that doesn't take into account each unit STARTING UP... I further realize this doesn't take into account several other things like hair dryers, curling irons, blenders, vacuums, power tools, the higher draw stuff... but those are also devices that are almost never on and can easily be controlled (unlike a fridge or AC condensor, for example). They are also devices that would likely pop their individual 15 or 20 A breakers before allowing the house to hit 100A anyway.
So, to make sure I understand how this works... for the cable running from meter to panel on the 100A MAIN... that should be 100A **PER LEG** - correct?
Meaning, 100A service really means 100 on each SIDE of the panel. So the Tesla will be 40A on BOTH of course, because it's a 240V. AC and Furnace obviously the same. Let's assume that CAR and AC (or furnace) use even 60A across 240 (so, each leg)... that leaves me with 40A on each leg for all the 120V breakers, right?
Do most people feel that 100A is more than sufficient, or would you, to be extra cautious, bump service to 200A, which in my case, may cost several thousand and take me out of the running for the car anyway.