wire size for motor

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dpeter

Member
Location
Indianapolis, In.
Occupation
elevator mechanic / building maintenance
I will be changing out a motor for an elevator and want to prewire the flex to controller to make it quicker and easier. 77 FLA and according to 430.22(C) I can use 58% of that from controller to motor. No problem. 430.22(E) says 85% for intermitent duty of which I have. Here is the question... How are these reductions applied? Do I take 85% of 77 and then apply the 58% to that result? I come up with 37.9 amps to choose wire guage with. Is this right?
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Are you pulling 6 conductors from the controller to the motor? If so I think you are correct. Note that in the 2011 code the 58% has been increased to 72%.
 

dpeter

Member
Location
Indianapolis, In.
Occupation
elevator mechanic / building maintenance
Yes there are six leads to the motor and it will be running in delta, and also I am using the 08 NEC. Did the 85% for intermitent duty stay the same?
Thanks for the confirmation, Doug
 
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