Lengths in bold type meet the National Electric Code ampacity only for individual conductor 60°C or 75°C cable, in free air or water, not in magnetic enclosure or conduit. If any other cable is used, the National Electric Code as well as the local codes should be observed. Flat molded and web cable is considered jacketed cable.

Cable lengths in Table 11 & 11A allow for a 5% voltage drop running at maximum nameplate amperes. If 3% voltage drop is desired multiply Table 11 and 11A lengths by 0.6 to get maximum cable length.

Table 11 & 11A is based on copper wire. If aluminum wire is used, it must be two sizes larger than copper wire and oxidation inhibitors must be used on connections.

EXAMPLE: If Table 11 & 11A calls for #12 copper wire, #10 aluminum wire would be required.

The portion of the total cable length which is between the supply and single-phase control box, with a line contactor, should not exceed 25% of total maximum allowable to ensure reliable contactor operation. Single-phase control boxes without line contactors may be connected at any point in the total cable length.

Contact Franklin Electric for 90°C cable lengths.

1. From Table 11 & 11A, a 3 HP motor can use up to 300 feet of #10 AWG cable.
2. The application has 160 feet of buried #10 AWG cable.
3. 160 feet ÷ 300 feet (max allowable) is equal to 53.3% of max allowable.
4. 100% - 53.3% = 46.7% remaining of another size cable.
5. 310 feet (well head to motor) is 46.7% of max allowable length of another cable size.
6. 310 feet ÷ .467 (46.7%) = 664 feet is max allowable.
7. 664 feet is less than or equal to what size cable in Table 11 or 11A under the 3 HP listing? The table shows #8 is good for 470 feet, which is too short. #6 is good for 750 feet, therefore #6 can be used for the remaining 310 feet.