My apartment has a main 50A circuit breaker, and several small appliances with the normal total current never exceeding 40A. There are also 3 240V appliances with higher nominal power: one is 3350W, and two are 5500W. Each is connected to its own circuit breaker.
In normal everyday use these 3 are very rarely used on their highest Wattage, and hardly ever I have more than 2 powered on at any given time. So normally the circuit operates easily under 40A.
If all three are powered on their high-ends, however, that would generate a ~59A current and activate the main circuit breaker, shutting off all power.
What I want:
The main circuit breaker is 4 floors below the apartment and it is managed by the building and the power company so I just can't replace it. But there's no damage that can occur from shutting down any of those 3 appliances, particularly the 3350W one.
I want to establish a first line of defense against total shutdown by first disconnecting only the 3350W appliance if the total current surpasses 40A. If the appliance is already off, or if the current remains over 50A after it is disconnected, then the main breaker would be activated shutting down the entire circuit.
Is it possible to design the circuit to make this happen? how or why?
Edit with answers to the comments:
- This is a biphasic installation and I have both 120V and 240V.
- I do have a distribution panel inside the apartment, feeding from the 50A master. This panel has 16 slots I can fill with single or double breakers.
- I don't have a master breaker in the panel. I thought of adding one but didn't see much value in limiting the overall capacity below 50A until I started thinking of this. It is possible to add one, though.
- The appliances are one Oven (1000W to 3350W) and two Showers (500W to 5500W each). The reason I wanted to cut the oven is actually practical: you don't want to risk your shower breaker tripping and having to finish in cold water.
- These are the only appliances on 240V lines, by the way and each has their own double-breakers. 120V holds the refrigerator, freezer, light bulbs and all other outlets and they are split in shared breakers by room iirc.
- I know I could just set the house rules and instruct everyone to not use everything at once - I was just wondering if there was a way I could be a little more foolproof.