I thinka little refresheris needed here ... and I apologize for not doingit in my first post!
The NEC tables arewhat you use to size your wire. I don't have a codebook handy, but I'm pretty sure that the single-phase table has a 7-1/2hp entry. The table then gives you the amps you use to size the wire.
The nameplate amps are what you use to size your overcurrent protection - your fuse or breaker. Since this is a motor load, you will most likely size them quite a bit larger than your FLA. How much larger depends on the exact type of OCPD.
If the pump is really that big, you won't be controlling it directly; there will be some manner of starter. The various float switches just aren't made for the starting current (appx. 150 amps) that the thing will draw.
With a starter, you have 'heaters,' or overload devices. These you size / set just a bit more than the maximum running current that you actually measure. The most important factor influencing the motor load is the pump 'head,' or how high the pump must pump the water. This amount will not change.
A final note: it is essential to set your floats so that the pump is always submerged (assuming a submersible pump is used). The waterisneeded to cool the motor. You also want to set the floats for as large a gap between 'pump off' and 'pump on' as posible; you don't want the pump short-cycling. If there are two pumps, choose pumps large enough that any one can handle 'normal' loads on its' own.
I've never seen a nameplate that gave the 'horsepower' in any but the 'usual' values. Examples would be 5hp, 7-1/2hp, 10hp. I've never seen, for example, a 6hp motor nameplate - let alone a '6.7hp' tag. In any event, a sewage pump that size would be too large to place by hand, and have at least a 3" discharge pipe. Check your facts.
