Final answer:
The item that is not a motor branch circuit major functional block is c. Motor frame type and shaft size,
which are mechanical characteristics of the motor and not part of the branch circuit's electrical components.
Step-by-step explanation:
The component that is not a motor branch circuit major functional block is c. Motor frame type and shaft size. Major functional blocks of a motor branch circuit typically include a. Motor branch-circuit short-circuit and ground-fault protection, these devices such as circuit breakers and fuses interrupt excessive currents to prevent thermal hazards.
b. Motor controller and disconnecting means is responsible for starting, stopping, and disconnecting power to the motor. Lastly, d. Motor overload protection, which protects the motor from overheating due to excessive current.
It is important to note that the motor frame type and shaft size are mechanical characteristics associated with the motor itself and not the electrical circuit's components.
Safety devices such as the three-wire system, ground fault interrupter (GFI), and isolation transformer are essential in preventing thermal and shock hazards by using attributes such as grounding and induction.