I’m taking a practice test, and one question asks for the minimum branch circuit size of a certain 3-phase motor. It does not specify what the motor is for or that it is a continuous duty motor, but the given answer requires you to treat it as one. Is this a rule, and is it somewhere in the code? I want to know if I was wrong or if the test was poorly written.
Are motors assumed to be continuous duty if not specified?
- Thread starter Joe E
- Start date
Joethemechanic
Senior Member
- Location
- Hazleton Pa
- Occupation
- Electro-Mechanical Technician. Industrial machinery
I've seen proprietary motors that as components didn't have the duty cycle, and I know they weren't 100 % duty
ptonsparky
Tom
- Occupation
- EC - retired
Minimum branch circuit size, as in conductor, is usually 125% of NEC table Amp value for the motor. It doesn’t have anything to do with continuous duty.
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You would need to fill us in on details of the question.
- Location
- Illinois
- Occupation
- retired electrician
For tests, without any additional information, the answer will be based on the parent text of 430.22. If they want other than continuous duty, they will give you the type of information found in 430.22(E).
Eddie702
Licensed Electrician
- Location
- Western Massachusetts
- Occupation
- Electrician
I could be mistaken but I thought if you added the standard 125% you were covered for continuous duty
Deltaforce
Senior Member
- Location
- India
- Occupation
- Electrical Engineer
The OL relay of motor also to set 125% avoid trip continuous duty. I saw some motor manual say simply set OL relay 100% not stating continuous duty or not in India.
ptonsparky
Tom
- Occupation
- EC - retired
The motors are allowed to run at 25% overcurrent?