So I purchased a 2 bedroom/2 bathroom condo in Arizona not too long ago. It was built in 1984. I recently took a good look at my load center and I see there is no main breaker installed. The label on the door of the box says it is a 125amp service. Wouldn't a main breaker be required or is that a local building code issue?
My GE panel (150 A service) installed in 1970 in our tract houe has no main 150-A breaker. This is a so called 'split bus' panel. There are four 2-pole breakers in an upper section (30 A, 40 A, 50 A and 60 A, respectively, for the clothes dryer, a/c condensing unit, electric kitchen range, and a "main section" breaker which feeds all the branch circuits in a section below. The output of the "main breaker" is connected to a separate bus below by heavy wires, hence the term "split bus".
So I need "four flips" to shut off all power in the house. This kind of panel is no longer manufactured, and at some point I plan to replace it. This may be what you have.
Or you may have a main breaker in a panel under the meter. I have seen an arrangement where a 2-pole main breaker is in a panel under the meter outside and the other 2-pole 240 V breakers are there too. Then in a separate panel just on the opposite side of the wall inside there is a panel which contains just single pole breakers for the branch circuits with no main breaker for all the branch circuits. I think that technically the inside panel may be a sub-panel.