Motor Overloads

[arnettda]

On a single phase motor, that has overloads installed in the motor contactor that need to be manually reset, is one required in each leg? I do not see where it says that one in each leg is required? It makes sense but I can not find it. I replaced a motor on a contactor that only had one overload in it? Thanks

 

[petersonra]

On a single phase motor, that has overloads installed in the motor contactor that need to be manually reset, is one required in each leg? I do not see where it says that one in each leg is required? It makes sense but I can not find it. I replaced a motor on a contactor that only had one overload in it? Thanks

Only in ungrounded conductors.

 

[infinity]

On a single phase motor, that has overloads installed in the motor contactor that need to be manually reset, is one required in each leg? I do not see where it says that one in each leg is required? It makes sense but I can not find it. I replaced a motor on a contactor that only had one overload in it? Thanks

Are you referring to a 208 or 240 volt motor?

 

[arnettda]

Are you referring to a 208 or 240 volt motor?

Yes a 240 volt single phase motor

 

[LarryFine]

Disconnection requires opening all ungrounded conductors, control doesn't.

Monitoring the current in only one line is adequate for single-phase motors.

 

[Eddie702]

On a single phase motor you only need an overload on one leg. Three phase needs 3 although only two were required around 60 years ago

 

[kwired]

I agree with Larry and Eddie. Operating voltage or even which one may happen to be the grounded conductor has no impact on this. Overload device only need to be in one line, what goes out on one line must come back on the other so a device in either supply conductor will do the job.

 

[Tip DS]

I'm going to agree; According to Table 430.37, number and location of Overload units for all 1-phase motors is 1.