Motor overloads

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arnettda

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430-32A1 says overload protection shall be no more than 115-125% of name plate. 430-32c gives an exception to go a little higher.
The inside of my starter says to use name plate value and chart on cover. Where would you start. This is not a motor that I want to have problems with so I am going to go the 125% larger from the start to avoid a late night call back. Is this the best way to go about it or should I start from the exact name plate and see what happens?
Thanks
 
Is the motor marked with a service factor of 1.15 or highter or marked with a temperature rise of 40 degrees C or less?

If not then you can only go to 115% not 125%.

Chris
 
The NEC is about general 'not to exceed' requirements. The NEC is not a design manual.

The manufacturer's instructions are specific for their equipment. Their selection table has been created to allow you to choose the correct protection based only on FLA and still meet the NEC. The manufacturer has probably also provided easy to follow instructions on how to accommodate different ambient temperatures and service factors.


I would even go so far as to say, if you do not follow the instructions included with the starter you are violating 110.3(b).
 
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