NEC Motor Load Calculations Example

Very well laid ou,t with Code articles as references. Nice job!

You dont need the FLA to do these calculations?

The overloads are calculated at nameplate FLA, right? Everything else is calculated from the FLC from from 430 tables , am I right about this?

Your videos are great. Please do more ..

I thought if you rated your ocp at 250% it would be the next "lowest" size breaker or if it's sized at 125% it would be the next "highest" size breaker? Great Info sir! 👍

Where does table 430.22(E) fall in these steps? If asked for any of these rating percentages? Answer be helpful

Wouldn’t you size your OVERLOADS to your FLA on the motor? Not your FLC from the code book?

When you size breakers for motors, wouldn’t you round down to the next standard circuit breaker size?

Great example!! Way to walk through it!

Why is the first wire size not # 18?

I think you made a small mistake by multiplying your overload protection device with your FULL LOAD CURRENT instead of your FULL LOAD AMP??

I am doing 50 HP [FLC= 65A, 65A*125% = 81.25A got Conductor size AWG 4] and 250 HP [FLC= 302A, 302A*125% = 377.5A got Conductor size AWG 500MCM table 310.16(75 ,Copper)]. For 50 HP - I am doing 65 A * 250% = 162.5 Amp breaker. But from ugly book, for 50 HP size breaker-150A. Same for 250 HP - 302 * 250% = 755 A. Should I not go up and standard size of breaker?

EXCELLENT VEDIO👌👌🙏🙏

Thanks so much send more

Some guys are just cut out to be teachers, nice job.

Arent you supposed to calculate the Overload from nameplate amps????

thank you, very helpfully for me

i have same question as others on using 75C when ampacity column. 75C can be used only when terminations are also 75C. why is 75C used here?

Information is thrown out very thoroughly. Thumbs up!

Well put!! Great teacher.

I took this guys full prep class a few years ago. Passed my masters exam on the first try thanks to it! great teacher

what nec edition is this ?

I am now very confused, but anyways I only know things for residential wiring only, I thought 14awg must use 15a breaker to protect the wire

How can i get these work sheets ??

Beginer here.. dont understand most of it 😅

Last i checked. 1.4 was less than 1.5

Mis heard him

why dont protect the wire?

So I just did this by calculator and field knowledge on wires and experience wiring things actual amperage it’s 7.7 not 6 learning ohms law helps a lot and makes easy to calculate by using the calculator

For Step #6, why wouldn't you add 150A to 20A for the remaining motor? Why did you only add the FLC and not the Branch Circuit protection from step #4 like you did for the larger motor?

Thank you so much about to go for my exam shitting bricks this helps so much

fascinating

Super helpful! Thank you

Could you please tell me why the 40hp motor doesn't have any starter

I've noticed you use 75° column for the branch ckt conductor size. However I was told to use 60°C column for circuits rated 100 amperes or less (per NEC 110.14-C) regardless of conductor insulation rating. Was there an exception that I missed?

Service factor is 1.4 and the code is 1.5 or grater to be × 125%. If is not 1.5 por greater it should be × 1.15.

FLA not equal to flc? Why put FLC?

There is a standard 70 amp breaker by the way

what happens if the motor is 400V AC?

he messed up on overload for big motor other than that I like the way he teaches

great great great instruction!

On step #3 if its THWN-2 at 9.5 amps wouldn't the answer be 18 for copper? Or is it 14 because of the temp rating? Confused. I understand how you got the answer for the 65 amps just not the 9.5 amps.

Amazing video thanks!

How do we factor distance when calculating wire size?

Thank You!!

How do I get a copy of all these steps?

The way you calculated magnetic only CB current isn't correct , this is the Magnetic trip current not the rated current

I think the wires are undersized, and the main CB is undersized. The wires should be 2 or 1 levels up the ampere rating of their circuit breaker. Load < breaker amp < wire amp. Instead, you are taking into account the overload relay.

I think there's a mistake on step 2, you should calculate overload with FLA nameplate, not FLC and there is not fuses 0r brakes 7.6 or 65 amps on table 240.6 A nec2023 for overload