Motor fuse sizing

[JdoubleU]

How do you determine what type of fuse to order? Lets just say that the motor requires a 30amp fuse. How do I know what type to get? What is the most common?

 

[cadpoint]

What is the exact type of equipment that your fusing, what is the size, name plate, dual usage, like motor compressor combination.

Bussman fuses per a search engine, other type of fuses are listed as well.

 

[JdoubleU]

Well, lets just say fan motor vs compressor

 

[cadpoint]

It not a short and sweet answer!

See Figure 430.3, Since no other information was provided. (read all) and jump forward/or back to other article in this articles!

430.22 Single Motor (read all) then you can use Table 430.22(E)

Since we'll all assume this is a simple motor.

 

[JdoubleU]

Thank you

 

[kwired]

How do you determine what type of fuse to order? Lets just say that the motor requires a 30amp fuse. How do I know what type to get? What is the most common?

You can't say it requires a 30 amp fuse before you determine what type you will be using. You need to determine what type to use before determining what the trip rating is, as each different type will have different current/time trip curves. Then with a motor you need to know about starting current characteristics for the motor along with how the load may effect those characteristics.

 

[m sleem]

I was told before in this forum the ordering of the fusible disconnect switch is more accurate by HP rating.

 

[Besoeker]

What is the exact type of equipment that your fusing, what is the size, name plate, dual usage, like motor compressor combination.

Bussman fuses per a search engine, other type of fuses are listed as well.

FWIW it's Bussmann.

 

[kwired]

I was told before in this forum the ordering of the fusible disconnect switch is more accurate by HP rating.

The switch does need to be rated for the horsepower of the motor or more but that doesn't always mean you will need the maximum size fuse that will fit in the fuseholder either.