Elevator Load on 100A Residence

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DSamson

DSamson

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San Francisco, CA
I'm bidding a job where they are adding an elevator to an existing residence. The residence has 100 Amp service (fuses, not a breaker). The only significant exisiting load is an oven (6.1 kW nameplate). (everything else that makes heat is gas)

Here's all of the data the elevator sub provided:

220V 30A to our disconnect, and
120V 15A to our disconnect

Motor
5 HP, 220V, 60 cycle, single phase, 21 "full load amps", 126 "starting amps", class F insulation

My questions are:

1) What load do I include in my service calculation for this elevator?

2) If the 100A service is still sufficient, does it need to be increased for the locked rotor current of the elevator motor when it starts up? The exsiting main disconnect for the building is fuses.

Looking at Table 430.151(A), I get a locked rotor current of 168A.

From Table 430.110 tells me I need 115% of the full load current for the disconnecting means.

I get a full load current of 28 Amps, from Table 430.148. (Single Phase, AC) It looks like the elevator sub is treating it like a DC motor. His Full Load Amps of 21 seems to come from Table 430.147, 5 HP DC motor.

I'm a little stuck at this point.

Any help with the two questions above would be appreciated.

Thanks
 
220.18
(A) Motor-Operated and Combination Loads.....For circuits supplying loads consisting of motoroperated utilization equipment that is fastened in place and has a motor larger than 1⁄8 hp in combination with other loads,
the total calculated load shall be based on 125 percent of the
largest motor load plus the sum of the other loads.

Use the FLC in Table 430.248 (Full-Load Currents in Amperes, Single-Phase
Alternating-Current Motors) for load calculations. You need not use RLC.

Don't forget to add in additional loads from the elevator other that the motor.

If I remember the actual value you need to add for the service calculation is 125% of the motor FLC as per the above mentioned table plus the rest of the load...(lights etc.....whatever the 15A cir is for)
 
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