we have a special type Freezer, it is single phase 240v, 60 hz, the full load amperes are 10A, I need to calculate the breaker size for it according to NEC.

 

My calculations are:

FLA * 1.75
10*1.75=17.5 240.6(A) and 440.22(A) as per NEC.


Am i doing the correct calculation?

 

It is difficult to know the electrical code when we can't tell what country you are in.

 

Where I live, the breaker in the distribution board protects the wiring of the installation and not the appliance plugged into a socket. It should have its own integral protection.

 

Where I live, the breaker in the distribution board protects the wiring of the installation and not the appliance plugged into a socket. It should have its own integral protection.

Same in the USA and CAN; likely also in the EU.

Breakers at the distribution panel are chosen based on the wire gauge of the branch circuit; not on the individual appliance...

 

It's not a continuous load, but you have not specified distance to the load. 500 or 30' could make a difference.
So the breaker would be the next size up after doing the voltage drop calculations. I believe you want less than 3%.
If it were continuous - on or more than 3 hours at a time, I believe, sizing would start at 125% or (1/0.8).

 

It's not a continuous load, but you have not specified distance to the load. 500 or 30' could make a difference.
So the breaker would be the next size up after doing the voltage drop calculations. I believe you want less than 3%.
If it were continuous - on or more than 3 hours at a time, I believe, sizing would start at 125% or (1/0.8).

These calculations should be done during the design of the electrical installation. This will ensure correct sizing of the wire gauge of the branch circuit. The size of the breaker will then relate to the current-carrying capacity of the particular gauge of wire used, but as was mentioned before, this has no relevance to the needs of the appliance which should have its own integral overload cut-out or other form of overload protection.