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Fuse protection of two small motors on same circuit.

M

marine_sparks

New User
Location
seattle
Occupation
retired
I'm looking at a dual motor system with two 230v, 260 watt single phase motors that always run at the same time. One set of capacitors starts both motors. Protection is by a single external 6a fuse, and thermal protection devices inside each motor. I calculated FLA of each motor at 1.4 amps.

Can this single fuse protect each motor from overcurrent?
 
Last edited:
don_resqcapt19

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The fuses supply the short-circuit and ground-fault protection, the internal device in the motor provides the protection from overloads.
The code rules would require a maximum protection of either 5.6 amps if the fuse is a one time, or 3.85 amps if the fuse is a dual-element fuse, but permitted to be rounded up to the next standard size fuse as listed in 240.6. The next standard size for fuses above either of those current levels is 6 amps, so the 6 amp fuse is compliant.
 
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