need help and suggestion what action and code?

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wht is the appropriate action if the label on a motor controller or the nameplate on other electical equipment is marked "maximum fuse size"?
where in Nec code to support this action?
 

Ponchik

Senior Member
Location
CA
Occupation
Electronologist
it means the maximum OCPD for that motor can not exceed that rating.
Basic example:
Motor name plate: 5 HP, @ 240Volts with max 35A fused protection.
Table 430.250 has FLA of 15.2A
Then multiply 15.2 x 125% = 19A This is what your conductors needs to be sized for.
Install 12awg conductor
You can install a 35A fused protection

Table 430.52 tell us the maximum OCPD for motor branch circuits and ground fault. In your case you need to follow what the instructions or the label says.

I hope this helps. i am sure others will jump in with better explanation.
 
it means the maximum OCPD for that motor can not exceed that rating.
Basic example:
Motor name plate: 5 HP, @ 240Volts with max 35A fused protection.
Table 430.250 has FLA of 15.2A
Then multiply 15.2 x 125% = 19A This is what your conductors needs to be sized for.
Install 12awg conductor
You can install a 35A fused protection

Table 430.52 tell us the maximum OCPD for motor branch circuits and ground fault. In your case you need to follow what the instructions or the label says.

I hope this helps. i am sure others will jump in with better explanation.
thanks for the information.
 
it means the maximum OCPD for that motor can not exceed that rating.
Basic example:
Motor name plate: 5 HP, @ 240Volts with max 35A fused protection.
Table 430.250 has FLA of 15.2A
Then multiply 15.2 x 125% = 19A This is what your conductors needs to be sized for.
Install 12awg conductor
You can install a 35A fused protection

Table 430.52 tell us the maximum OCPD for motor branch circuits and ground fault. In your case you need to follow what the instructions or the label says.

I hope this helps. i am sure others will jump in with better explanation.

I though follow the instruction of label or "Name Plate" only apply to HVAC equipment only.
with motor equipment we use table 430.52 to find fuse size then multiply 1.2
 

dkidd

Senior Member
Location
here
Occupation
PE
NEC 110.3(B) installation and use. And if the nameplate says "fuse", without stating that circuit breakers are acceptable, then you must use fuses.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Assuming three phase then use T. 430.250. Thus for a 5 hp motor rated 240V you would use 15.2 amps. Then multiply by 1.25 for the minimum conductor size. The OCPD can be based on the nameplate for that.
 
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