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	Subject - How small can my elevator conductors be? LIVEWIRE I have a 40HP elevator. The manufacturer recommends over-current protection with 100A dual element fuses or a 125A shunt trip circuit breaker. A. What is the minimum size the NEC will allow my conductors to be? Assume 75 deg C lugs. Please state NEC references. B. How do I know whether to use fuses or the circuit breaker? LIVEWIRE Assume 52 FLA. Ryan_J How is overload protection being established? Is it seperate from the ground falut and short circuit protection of the motor? We also need to know the voltage and phase of the motor. See NEC Table 430.150 (or 148). Also, 620.61. Gives us a little more info and I think we can get you through this. :) cs409 as Ryan stated.....need more info,,,,,but for the most part elevator motors most often than not are intermittent duty.....table 430-22(b) read art. 620 look at 620.13 .......havent messed with elevators(off shore drilling rigs) sinse 74ishhhhh. keep us updated... oh,,,did u know that otis elevator has no need for an elevator in its corp. headquarters! LIVEWIRE Ryan, 460/3V - I must have snuck the 52FLA in on you. Overloads protection is provided in the elevator controller by the mfgr. However, we will assume overload protection is also being provided by a branch circuit protective device "not exceeding the level in Table 430.52". JimmyDee I'm sure that in Michigan, the elevator installation company gives the specs for the feed to the disconnect and that is that. They do the rest of it. We didn't like it but all the elevator stuff comes under their codes and installation supervision. You as an electrician tough anything on an elevator, you may be in violation of the law. Jim Ryan_J 100 Amp fuse, max. 430.52 150 Amp (inverse time) breaker, max. 430.52 Both sized using the "next size up rule". 430.52(C)(1), 240.6 Conductor: 6 AWG, regardless of overcurrent rating. 310.16, 430.6(A)(1) LIVEWIRE Gee, I didn't have any fun with this one at all.... Let's try Part B: How should I decide whether to use the circuit breaker or the fuses? LIVEWIRE Ryan, How about 620.13(A) reference to 430-22(E). It looks like the conductors could be as small as #8, unless the AHJ is even more liberal. Ryan_J Good call. I missed the 85% column. You could use #8. As far as the breaker vs. fuse goes....I don't know. Will available fault current be an issue? Generally speaking, fuses have higher AIC ratings than breakers. With the contribution from the motor, perhaps fuses are a way to go. What did you have in mind? LIVEWIRE I'll rephrase Part B: B. Under what condition must you find a shunt-trip circuit breaker installed at the site? LIVEWIRE You must install a shunt-trip circuit breaker in the elevator machine room if the machine room is sprinklered. The shunt-trip circuit breaker is controlled by a heat detector whose activation temperature is below the discharge temperature of the sprinkler head. If there is a fire in the machine room, the elevator equipment is deactivated before the sprinkler head discharges. If machine room is not sprinklered, a disconnect can be installed in lieu of the shunt-trip circuit breaker. cs409 you should have a good headache by now,,,,,sounds like you came up with some good info! so how is this project going? working with the elevator guys? LIVEWIRE The only thing I've ever done that brought the elevator inspector running was to put the company beer frige in the elevator machine room and lock the door. YukonRay That has got to be the best place for it. I hope you had a good supply.