The Main Circuit Breaker WILL not provide this function.
I am an electrical engineer explain please.
Short Answer: Insufficient Air Gap in Breaker to prevent arcing and causing a shock hazard to Power Company Repair personnel.
Long Answer:If you do not use some sort of mechanical means of preventing power to be sent out to the gird, you may injure or kill a linemen. The 120 and 240 volts you have in your homes comes from a transformer that steps down high voltage, anywhere from 2400 up to 4100 volts typically in a residential area. If close to a commercial area the voltage can be as high as 13,000 volts.
The power you send out onto the grid will get stepped up to that higher voltage. A linemen working on those lines, fortunately they work on dead lines as if they were live, may come in contact with that voltage.
Linemen are constantly checking for power coming back at them on a line that should be dead. If they see voltage for no good reason, they will track it down, and cut the lines to your home.
You will be the last person to get power back, and they will have the local inspector with them, to inspect your system. And you will effect any repairs or eliminate any code violations before power is restored.
This is assumes no one gets hurt. Then criminal charges are in order.
There are manual transfer switches, automatic transfer switches, and devices that are simple interlocks between the two input breakers from utility and generator.
Either one must be used when connecting a generator to a system.
Look up your utilities website and look for their service requirements and it will explain about using these devices.
Why would the main breaker prevent power from getting in to the house but not out?
If the input mains are open I don’t see how a small generator will feed back to the utility.
I work for SQD.
Ok it works both ways. If the main breaker, when opened, has an insufficient air gap to provide protection then I am at risk too when I open the man bus b to work on my house circuits. I call total bu!!shit on this one. This is pure poppy cock.
LOL.