min. size for overloads

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ultramegabob

ultramegabob

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Indiana
what is the minimum size that a motor has to have overloads 120v, or could someone direct me to a chart online? I dont have any ref books with me, thanks....
 
It's not that easy. If I'm understanding your question correctly, you need to know the FLA on the name plate of the motor. Then look at 430.32.
 
I agree with Iceman on the reference to 430.32 and 430.33
I don't happen to agree with the FLA statement.
If the motor is Continuous duty and more than 1 HP, it needs OL protection.
If the motor is 1hp of less and automatically started it needs OL protection
If the motor is 1hp or less and non-automatically started and not permanently installed the branch circuit device may possibly serve as
OL (see 430.32D)
If the motor is intermittent or similair duty the branch circuit device might be the OL protection.

If you look at 430.42, and had to pick an answer, "not over 1hp" would probably be the best answer.

As you can see, there is no simple answer.
 
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augie47 said:
I agree with Iceman on the reference to 430.32 and 430.33
I don't happen to agree with the FLA statement.
If the motor is Continuous duty and more than 1 HP, it needs OL protection.
If the motor is 1hp of less and automatically started it needs OL protection
If the motor is 1hp or less and non-automatically started and not permanently installed the branch circuit device may possibly serve as
OL (see 430.32D)
If the motor is intermittent or similair the branch circuit device might be the OL protection.

As you can see, there is no simple answer.
Click to expand...


I think your answering my question, I have a .75 hp 120v motor contiuous duty manually started with a switch, #12 wire protected with 20 amp breaker, permanently installed in a exhaust fan.
 
ultramegabob said:
I think your answering my question, I have a .75 hp 120v motor contiuous duty manually started with a switch, #12 wire protected with 20 amp breaker, permanently installed in a exhaust fan.
Click to expand...

then, the way I read NEC, it's permanently installed so 430.32(D) (1) will send you back to 430.32(B) and some type O.L. is needed.
Typically these installatiions have thermally protected motors (internal) or are protected by a "manual motor starter" resembling a wall switch.
 
augie47 said:
then, the way I read NEC, it's permanently installed so 430.32(D) (1) will send you back to 430.32(B) and some type O.L. is needed.
Typically these installatiions have thermally protected motors (internal) or are protected by a "manual motor starter" resembling a wall switch.
Click to expand...


the motor has a toggle or bat switch now, I was thinking that I need to change it to a manual motor starter....
 
unless the motor has integral thermal protection, I agree
 
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