Rpack22
Member
- Location
- Santa Barbara
- Occupation
- Electrician
Hey all! Hope everyone is doing well.
I'm installing a disconnect for an elevator and I wanted to make sure my math/NEC findings are correct.
The motor is a 15HP motor, unfortunately I don't have the nameplate yet so I'm just going to use a S.F. greater than 1.15 for this demonstration to check my math.
The electrical system is 3 phase 240v.
From my understanding, the FLC would equate to 42A, the overload protection would be time delay fuses rated at 60 amps each, branch circuit conductors #6 copper thhn, feeder OCPD (inverse time ckt breaker) at 100 amps, feeder conductors #6 thhn.
FLC - 430.248 --> 42amps
Minimum Overload Protection - 430.32 --> S.F. = 1.14; time delay fuses for inrush current 125%(FLC) = 60 amp fuses
Branch Circuit Conductors - 430.33 --> 430.22(E) --> @ 140%(FLC) = 58.8 amps = #6 copper
Feeder Conductors - 430.22(E) --> @ 140%(FLC) = 58.8 amps = #6 copper
Feeder OCPD - 430.52 --> 250%(FLC) = 105amps --> 100 amp inverse time ckt breaker (Don't believe next size up is allowable here)
Any input would be great. Thanks all!
I'm installing a disconnect for an elevator and I wanted to make sure my math/NEC findings are correct.
The motor is a 15HP motor, unfortunately I don't have the nameplate yet so I'm just going to use a S.F. greater than 1.15 for this demonstration to check my math.
The electrical system is 3 phase 240v.
From my understanding, the FLC would equate to 42A, the overload protection would be time delay fuses rated at 60 amps each, branch circuit conductors #6 copper thhn, feeder OCPD (inverse time ckt breaker) at 100 amps, feeder conductors #6 thhn.
FLC - 430.248 --> 42amps
Minimum Overload Protection - 430.32 --> S.F. = 1.14; time delay fuses for inrush current 125%(FLC) = 60 amp fuses
Branch Circuit Conductors - 430.33 --> 430.22(E) --> @ 140%(FLC) = 58.8 amps = #6 copper
Feeder Conductors - 430.22(E) --> @ 140%(FLC) = 58.8 amps = #6 copper
Feeder OCPD - 430.52 --> 250%(FLC) = 105amps --> 100 amp inverse time ckt breaker (Don't believe next size up is allowable here)
Any input would be great. Thanks all!
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