430.24

dec

Member
Ok..... I have gone over this article many times and still read the quantity 125% and thats great. What I don't understand is .....take several motors say five motors at 10 amps each. Now add them up. 50 amps total. Now take 125% of the largest. 10x1.25= 12.5. Now my total is 62.5 amps. That said... Why am I being told to just add 25% of the largest to the 50 amps to get my total amperage? I've ben told the math is the same- but go figure it yourself. 62.5 is not the same as 52.5.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Ok..... I have gone over this article many times and still read the quantity 125% and thats great. What I don't understand is .....take several motors say five motors at 10 amps each. Now add them up. 50 amps total. Now take 125% of the largest. 10x1.25= 12.5. Now my total is 62.5 amps. That said... Why am I being told to just add 25% of the largest to the 50 amps to get my total amperage? I've ben told the math is the same- but go figure it yourself. 62.5 is not the same as 52.5.
Because that is exactly what the code rule tells you to do. You are taking the largest motor at 125% which is adding 25%. You do not add 125% of the largest as that would be taking the largest motor at 225%.
 

dec

Member
430.24

125% of largest motor + FLA of all additional motors
(10 x 1.25)+10+10+10+10 = 52.5

The 125% already has the 1st motor FLA

Ok.............I see your point. Next time I'll try READING the article especially where it says "other". I just didn't connect the dots to realize it means "additional" motors. Thanks for your help.
 
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