Anything that is 240V will require a 2 pole breaker. If there is ever an over current, there is no guarantee that the over current will be present on both legs, so by using a double pole breaker, you are ensuring that if an over current happens, both legs will trip. Using only single pole breakers means that one leg could still be energized when you do not want it to be.
For a typical house in the US, a single pole breaker provides only 120V. A double pole breaker provides 240V.
It is always better to use double pole rather than single pole for large power, either phase to phase or phase to neutral.
However if you have 3 such appliances, which are not likely to be all in use at the same time, I would recommend a main DP breaker of 100 amp with an individual breaker for each appliance, preferably a RCBO. rated for each appliance.
RCBO is a residual current + overload device.
Residual current device trips the unit under earth fault and the overload side trips it on overload.
Appliances using these currents are not normally individually protected, so if your water heater say, is the only appliance in use and develops a fault, the breaker protecting it is 100 amp. 5 x full load current.
If they are 220 two phase you will need ganged Breakers. Look into the code and find out what is needed.
Ask the local building department when you get the permits, they can help you do it right.
All of them require double poles breaker to fuse both hot lines. Each device needs its own breaker in circuit, like 40A; 30A and 20A. And each device needs its own power socket.
Stove and drier are also need neutral line.
On a different 100 amp breaker, can it be done and would it be better to use single pole, I am looking for safety!?
