Low Voltage Motor Protection Article 430.36

Status
Not open for further replies.
C

corvalan

Member
Article 430.36

Comment 1: Article 430.36 of the code allows fuses for overload protection. To size the fuse for overload protection (as allowed by this article), I assume we have to use article 430.32 (A)(1) Separate Overload Device. So the fuse will be acting then as a separate overload device.

Question1: Is it correct to use article 430.32 (A)(1) Separate Overload Device to size the fuse when used as the overload device permitted by Article 430.36?

Comment 2: Since the fuse is used as an overload device, then there will ONLY be one overcurrent protection device in the motor circuit, the fuse. The fuse is acting both, as the short circuit protection and the overload device (obviously if sized according to 430.32 (A)(1).

Question 2: Is this correct?
 
corvalan said:
Article 430.36

Comment 1: Article 430.36 of the code allows fuses for overload protection. To size the fuse for overload protection (as allowed by this article), I assume we have to use article 430.32 (A)(1) Separate Overload Device. So the fuse will be acting then as a separate overload device.

Question1: Is it correct to use article 430.32 (A)(1) Separate Overload Device to size the fuse when used as the overload device permitted by Article 430.36?

Comment 2: Since the fuse is used as an overload device, then there will ONLY be one overcurrent protection device in the motor circuit, the fuse. The fuse is acting both, as the short circuit protection and the overload device (obviously if sized according to 430.32 (A)(1).

Question 2: Is this correct?
Click to expand...

what type of motor are you protecting? Single phase/three phase? I think the challenge you will have with this simple setup is having the fuses sized large enough to handle the starting current, yet sized properly to protect the motor from overload. This is why a combination of fuses or breaker and motor starter with overload protection is so common.
 
Jim1959 said:
what type of motor are you protecting? Single phase/three phase? I think the challenge you will have with this simple setup is having the fuses sized large enough to handle the starting current, yet sized properly to protect the motor from overload. This is why a combination of fuses or breaker and motor starter with overload protection is so common.
Click to expand...

This is a three phase motor. I am not discussing here the convenience or practicality, but if the installation is code compliant and if my interpretation of the code is correct.

Thanks.
 
Status
Not open for further replies.
Top