NEC User
Senior Member
- Location
- Marlboro, NJ, USA
I'm working on a project for an existing passenger elevator (not sure how often it is used).
The nameplate ratings of the elevator is 460V, 3 phase, 30 HP, FLA=40A, Nema Designation A. I
The nameplate also states:
Starts/Hour = 80
HP = 40
FLA = 52
Duty = 30 minutes
The nameplate also states:
Starts/Hour = 120
HP = 30
FLA = 40
Duty = 60 minutes
Existing conditions feeds the elevator using a 40A inverse time breaker and a disconnect with a 45A fuse. Is this correct? I wouldn't think so.
My calculations are as follows:
Size the disconnect per 430.110. 1.15 x FLA = 1.15 x 40 = 46A minimum. Then round up to the nearest size = 50A. (The existing condition is 45A fuse which I believe is not to code. Is this correct?)
Determine Overcurrent protection: Use Table 430.52 and inverse time breaker to get a factor of 250%. FLA x 250% = 40 x 2.5 = 100A maximum. (The existing condition is a 40A breaker which is significantly less than this maximum value I calculated. I wouldn't think the existing condition meets code.) What is the NEC overcurrent protection minimum?
Conductor size: Per my calcs, I need to ensure the conductors are sized per the breaker = 100A. I'm not sure of the existing conductor size. 430.22(E) allows me to size conductors for an ampaicity of not less than the percentage of the motor nameplate current rating shown in Table 430.22(E). For passenger elevators at 30 & 60 minute ratings it is 90%. Supposing I use this, then FLA = 40A x 90% = 36A. Then, I can size my conductors for 36A minimum. How does this affect my calculations? Does this mean that the 100A max circuit breaker calculation I performed above can be 36A or even 28.8A (28.8 x 1.25% = 36A)? If so, is the existing 40A breaker acceptable and what code section states this? And then then the 45A disconnect rating is acceptable to and what code section states this?
The nameplate ratings of the elevator is 460V, 3 phase, 30 HP, FLA=40A, Nema Designation A. I
The nameplate also states:
Starts/Hour = 80
HP = 40
FLA = 52
Duty = 30 minutes
The nameplate also states:
Starts/Hour = 120
HP = 30
FLA = 40
Duty = 60 minutes
Existing conditions feeds the elevator using a 40A inverse time breaker and a disconnect with a 45A fuse. Is this correct? I wouldn't think so.
My calculations are as follows:
Size the disconnect per 430.110. 1.15 x FLA = 1.15 x 40 = 46A minimum. Then round up to the nearest size = 50A. (The existing condition is 45A fuse which I believe is not to code. Is this correct?)
Determine Overcurrent protection: Use Table 430.52 and inverse time breaker to get a factor of 250%. FLA x 250% = 40 x 2.5 = 100A maximum. (The existing condition is a 40A breaker which is significantly less than this maximum value I calculated. I wouldn't think the existing condition meets code.) What is the NEC overcurrent protection minimum?
Conductor size: Per my calcs, I need to ensure the conductors are sized per the breaker = 100A. I'm not sure of the existing conductor size. 430.22(E) allows me to size conductors for an ampaicity of not less than the percentage of the motor nameplate current rating shown in Table 430.22(E). For passenger elevators at 30 & 60 minute ratings it is 90%. Supposing I use this, then FLA = 40A x 90% = 36A. Then, I can size my conductors for 36A minimum. How does this affect my calculations? Does this mean that the 100A max circuit breaker calculation I performed above can be 36A or even 28.8A (28.8 x 1.25% = 36A)? If so, is the existing 40A breaker acceptable and what code section states this? And then then the 45A disconnect rating is acceptable to and what code section states this?