> It's not unlimited since it's (by your own account) 15/3. That's a limitation right there, identical to your 150 amp service. And you can not exceed that limit period (you won't even get close to it, really). No need for a breaker.
It is one form of limitation, but it is not the most relevant.
The point is that Comcast has to pay for the transfer of data in and out of their network. So they have two choices:
* Meter your data transfer and charge a base fee for available bandwidth (just like commercial usage)
* Throttle your bandwidth so that you cannot exceed a set monthly transfer amount
Do you really want either? I don't. Assuming you want the later option, here's the breakdown:
250 GB -> 2,000 Gb (gigabits)
There are 2,678,400 seconds in a month.
2,000 Gb per 2,678,400 seconds
Reduced is: 0.0007467145 Gb per 1 second
Multiply by a factor of 1,048,576 (kilobits in a gigabit) and you get: 782.9868578256 kbps
To cap you at 250 GB per month (which their model is built around), you'd end up with an internet connection that is roughly the speed of an entry-level DSL connection (768 kbps DSL).
Does that make any sense to anyone? You can't simply wash away the cost of transferring the data in and out of their network with some government mandate.
The other option is to pay for metered bandwidth. This means the additional overhead of metering each customer, as well as the additional billing infrastructure. Not an impossible problem, but it's a lot of data to track, and the overhead is undeniable, so you'll end up getting more for less.
OR!
We could all cooperate and agree that there is a "typical" consumer use case with a soft ceiling of 250 GB of transfer per month. If can't operate within that ceiling, you should look in to a business-class connection where the pricing models fit your needs better.