I guess congratulations are in order to the OP's electrician for his successful smoke-screen, haha.
That said, it's an interesting topic and here are a few answers.
74AnimalA said:
aggiecody06 said:
4/3 2700 sq ft, one and half story with 3 car garage, main panel on outside of house
Even in New Builds, Many GAS Houses (Heat, Hot H2O, Range, Gas Dryer, etc) I have seen only a 150a Main Breaker. Believe in these houses, the only 220v is for the A/C.
All Elect Houses seem to have a 200 (Elect Heat, Range, Oven, Dryer, etc.) There will be many more 220 Breakers.
And it varies from local to local. There may be an Local Elect Code or Practice to install the Main Breaker based upon the Design Load. (Note NOT a EE or Licensed Sparky). Or it's the builder that can save $20 a house by accepting the smaller breaker. ????
In short, nearly every local code is going to follow the NEC for minimum sizing. Combine that with current supply chain issues, bulk purchasing power (buying 200A panels in bulk), cheap/good builders, you'll see a range of solutions here. I'm not a residential guy, but I think it's typical for 200A panels to come loaded with more space as well, so that factors into it.
ETA - I'd also speculate that some designers have taken advantage of the widespread adoption of LEDs and some other high efficiency appliances in new builds. Especially for lighting, the reduction in load is not insignificant.
74AnimalA said:
Oh and that 208v nomenclature. I have only actually seen that in Industrial applications which often use 3-phase power.
This is effectively true, but based on the circumstances. Many devices are listed for a range that allows them to be used on either a 208V or 240V supply. It has more to do with the practicality of how industrial facilities and residential neighborhoods are configured than a hard and fast rule
In a 3-phase system, the sine waves are offset by 120 degrees, so mathematically, the phase-to-phase voltage is 208V. Short distances and a high number of 208V-240V loads in industrial facilities makes this practical. It's not cost-effective running neutrals everywhere.
In a residential neighborhood, it's cheaper to keep everything single phase - It's not cost effective running phase conductors everywhere. Someone very clever figured out how to get two separate voltages by tapping and neutral/grounding the center of the load side of a transformer winding, so the phase to phase voltage is 240V, but the voltage between the phase and the tap is 120V. The sine waves are 180 degrees offset. It's an elegant solution.
74AnimalA said:
Now, why are your appliances, lamps etc listed as 110v, but your outlets say 115v? Keeping it simple. Then what is the difference between 220 & 240. Well, 220 comes from adding both 100 legs together. Then how did they get the 240? Even 115v x 2 Equals ???? (Hint it's not 240)
Between voltage drop and floating supply, it's pretty typical for system voltage to be listed at the
nominal value (120V) and loads to be listed at the low range they will work properly (110V), but they're all the same: 110V (load) = 115V = 120V (supply). Same for 240V systems. And 480V. And 6.9kV. Etc. For example, a 6.9kV (system voltage) motor is typically listed as a 6600V motor (load).
As alluded to in the above diagram, 120V (system voltage) x 2 legs definitely equals 240V (System voltage)
