# Load calculation exam. Help wanted.



## Martine (Jan 26, 2018)

For your motor question if it’s the 250%, you do 250% of your biggest motor’s amperage, then add the amperage without protection of your other motors on it to your total, add all those up and pick the fuse that’s even or the next one that’s smaller.

So 50x250%= 125A 
+9.8A
+56
+56
246.8A

You can’t go higher so you need to go to the next lower one which would typically be 225A, with a 400A sectional (might be the wrong term, I’m a frenchie) 

If someone wants to confirm how you do it in the US of A that would be grand.


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## EtrnlFlux (Aug 8, 2018)

Yea. So I looked at the two whole pages of explanation regarding this, and read it like twenty times. It gave some examples, but it kept talking about exception 1. Which I read, but it talked about 1300% of motor amperage and what not.

So then my expanded question pertaining to the motors is. If the their are TWO 50hp motors, does that change anything or do I still only do the multiplier to one of the motors and just simply add the second 50hp motor in and down size?


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## EtrnlFlux (Aug 8, 2018)

johngary2 said:


> Since you are in Washington State - I teach Exam Prep C-US-4-CEU-S.NET
> 
> 
> 1st you select the Amperage of the Motor FLC. (Full load Current) from 430.248 or 250 based on Single Phase or 3 phase motor.
> ...


When you said you can't round up a round up... BOOM. The part I was having trouble is, you got various scenarios that you round up. Ok I get it, but then I'm seeing this whole "You round down to the next lower breaker" and I'm sitting here, like whaaaa?

Thank you very much, that is a great phrase to use. What I was looking for.

NOTE: As for the other questions that I asked, I've talked to a few people, instructors included and have had them answered. As for anyone else that get stuck with a question that only provides the Amp of a device, but not a voltage, by consensus use what you know in the field. (Even though you may be told to take what you know and throw it out the window when taking the exam)


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