How do my appliances know to use solar first then grid electricity

[sponge]

I do not currently have a solar system, but thinking about it.
How do my home/appliances know to draw from the solar power first before grid power? If all the power is coming in to the breaker box, either from to grid into the fuse box or also from the inverter into the fuse box, what makes solar power be the first choice? They are both there at the same point and at the same time so to speak.
Thanks

 

[Andy™]

they don't... the solar simply puts out a slightly higher voltage than the grid voltage coming in