Starters and thermal overloads for motors
- Thread starter stevenb
- Start date
- Status
wayne123
Senior Member
- Location
- North Carolina
Re: Starters and thermal overloads for motors
According to 430.32 all motors over 1hp shall have OL protection.There are more than one way to protect a motor from OL, they are also in that article.If I am reading all of it correctly and none of the other methods are being utilized,i would call in an inspector to check his install if he refuses to make the correction
According to 430.32 all motors over 1hp shall have OL protection.There are more than one way to protect a motor from OL, they are also in that article.If I am reading all of it correctly and none of the other methods are being utilized,i would call in an inspector to check his install if he refuses to make the correction
B
bthielen
Guest
Re: Starters and thermal overloads for motors
I don't have a current code book in front of me but if memory serves, isn't 430.32 referring to continuous duty motors and not necessarily intermittent duty? I believe 430.33 discusses intermittent duty motors.?
Bob
I don't have a current code book in front of me but if memory serves, isn't 430.32 referring to continuous duty motors and not necessarily intermittent duty? I believe 430.33 discusses intermittent duty motors.?
Bob
wayne123
Senior Member
- Location
- North Carolina
Re: Starters and thermal overloads for motors
Ah yes! this is true. I guess we need to know what the motor is going to be used for.Personally I like to have OL on all motors over 1hp but according to the code only cont. duty motors apply.
Ah yes! this is true. I guess we need to know what the motor is going to be used for.Personally I like to have OL on all motors over 1hp but according to the code only cont. duty motors apply.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: Starters and thermal overloads for motors
All motors require overload protection, period, including intermitant duty. There are 4 methods, the most common is separate overload protection and internal overload (thermistor).
The size of the motor does not matter. The rules even apply to your bathroom exhaust fan, but it is impedance protected from overloads.
If the motor does not internal overload protection then external protection is required. the rules in art 430 are complicated, esp on overload protection. Take 15 minutes and read thru the section on overload protection.
All motors require overload protection, period, including intermitant duty. There are 4 methods, the most common is separate overload protection and internal overload (thermistor).
The size of the motor does not matter. The rules even apply to your bathroom exhaust fan, but it is impedance protected from overloads.
If the motor does not internal overload protection then external protection is required. the rules in art 430 are complicated, esp on overload protection. Take 15 minutes and read thru the section on overload protection.
pierre
Senior Member
- Location
- Westchester County, New York
Re: Starters and thermal overloads for motors
Steven
Part 3 of Article 430 permits integral overload protection of continuous duty motors, which I would classify this motor as. So before you get too excited find out if it does. If not then quote him section 430.32 and see how he responds. One thing to think about, overload protection is not required if the shutdown increases or creates a hazard.
Good luck
Pierre
Steven
Part 3 of Article 430 permits integral overload protection of continuous duty motors, which I would classify this motor as. So before you get too excited find out if it does. If not then quote him section 430.32 and see how he responds. One thing to think about, overload protection is not required if the shutdown increases or creates a hazard.
Good luck
Pierre
Re: Starters and thermal overloads for motors
I think if the motor is protected by a properly sized dual element time delay fuse, everything would be fine. For a 1.5 HP 460V motor that's a 4A fuse.
That's not the best idea since instead of just resetting a motor overload, you'll be replacing a fuse(s).
I think if the motor is protected by a properly sized dual element time delay fuse, everything would be fine. For a 1.5 HP 460V motor that's a 4A fuse.
That's not the best idea since instead of just resetting a motor overload, you'll be replacing a fuse(s).
- Status