How do you size fuses for a motor?

The overload protection is sized per the motor nameplate current rating, not the motor full load current (FLC) rating. Thus, 60A×1.25=75A. Overload protection shall not exceed 75A, so you need to use a 70A dual-element fuse [240.6(A) and 430.32(A)(1)].

How do you calculate fuse size?

To calculate a fuse rating, manufacturers work from a simple equation:

  1. Power (watts) = Voltage x Current (amps) What we really want to know with this equation is the current (amps).
  2. Amps = Watts / Voltage. So, let’s say we need to work out the fuse rating for a washing machine.
  3. 850/120 = 7.08 amps.

What type of fuse is best for motor protection?

Time delay fuses
Time delay fuses are the most useful fuses for motor branch circuit application. A time delay fuse can be sized closer to motor full load current, providing a degree of overload protection, better short circuit protection, and possible use of a smaller disconnect switch.

What is a 3 amp fuse used for?

Plugs for appliances rated up to about 700 watts should have a 3-amp fuse (coloured red). For example: 3A Fuse – Table lamp, standard lamp, television, video, computer, mixer, blender, fridge, freezer, power drill, jig saw, soldering iron.

How do we select fuses to protect electric motor?

Better protection is achieved when fuse ratings are based on motor actual FLA obtained from motor nameplates. Locate motor nameplate FLA in the column appropriate for the type of motor and type of protection required. Then select the corresponding ampere rating of the fuse from the first column of that line.

What is a 20 amp fuse used for?

A 20-amp screw-in fuse is generally used for outlet and appliance circuits wired with 12-gauge wire. A 30-amp screw-in fuse is most commonly used for circuits supplying electric clothes dryers or air conditioners. These circuits are wired with 10-gauge wire.

What is HRC fuse full form?

What are HRC Fuses? High Rupturing Capacity (HRC) Fuses are manufactured in a wide variety of shapes, sizes and electrical specifications. All these different types of HRC fuses are designed to protect circuits in specific applications.