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Drop Wire Selection and Combining

 

 

For a printer friendly PDF, please click here.

 

Drop Wire Selection Table for Deep Well Pump

Motor Rating (Single Phase)

Cable Size / Maximum run in feet

HP

Voltage

#14

#12

#10

#8

#6

#4

#2

1/2

115V

100'

160'

250'

390'

620'

960'

1460'

1/2

230V

400'

650'

1020'

1610'

2510'

3880'

5880'

3/4

230V

300'

480'

760'

1200'

1870'

2890'

4370'

1

230V

250'

400'

630'

990'

1540'

2380'

3610'

1 1/2

230V

190'

310'

480'

770'

1200'

1870'

2850'

2

230V

150'

250'

390'

620'

970'

1530'

2360'

3

230V

120'

190'

300'

470'

750'

1190'

1850'

5

230V

0

0

180'

280'

450'

710'

1110'

7.5

230V

0

0

0

200'

310'

490'

750'

10

230V

0

0

0

0

250'

390'

600'

15

230V

0

0

0

0

0

270'

530'

Motor Rating (Three Phase)

Cable Size / Maximum run in feet

HP

Voltage

#14

#12

#10

#8

#6

#4

#2

3

230V

210'

340'

540'

860'

1340'

2080'

3170'

5

230V

0

200'

320'

510'

800'

1240'

1900'

7.5

230V

0

0

230'

360'

570'

890'

1350'

10

230V

0

0

0

270'

420'

660'

1010'

15

230V

0

0

0

0

290'

450'

690'

20

230V

0

0

0

0

0

350'

530'

25

230V

0

0

0

0

0

260'

430'

30

230V

0

0

0

0

0

0

350'

2

460V

1300'

2070'

3270'

5150'

8050'

3

460V

1000'

1600'

2520'

3970'

6200'

5

460V

590'

960'

1500'

2360'

3700'

5750'

 

7.5

460V

420'

680'

1070'

1690'

2640'

4100'

6260'

10

460V

310'

500'

790'

1250'

1960'

3050'

4680'

15

460V

0

0

540'

850'

1340'

2090'

3200'

20

460V

0

0

430'

650'

1030'

1610'

2470'

25

460V

0

0

0

530'

830'

1300'

1990'

30

460V

0

0

0

430'

680'

1070'

1640'

40

460V

0

0

0

0

0

790'

1210'

50

460V

0

0

0

0

0

640'

980'

 

Can you combine drop wires of different gauge?


Yes! You may combine, 2 or more, different gauged (AWG) wire for your installation. Use the formula below to ensure that National Electrical Code (NEC) requirements are met.

Formula:

(Wire1 Length ÷ Max Run1) + (Wire2 Length ÷ Max Run2) + ... ≤ 1.00

Where maximum run is the maximum length permitted for that specific gauge of wire. See our drop wire selection table for maximum run information.

Example:

You have 375 feet of #6 wire buried between the service entrance and the wellhead. A new 3HP 230V single phase pump will be installed to replace a smaller pump. The new pump will be set at 200 feet below the wellhead.

What wire gauge is suitable?

From the drop wire selection table, #6 can be use for up to 750 feet and #10 for up to 300 feet, (375 ÷ 750) + (200 ÷ 300) = 1.167 which is greater than 1, so #10 can’t be used; #8 wire can be used for up to 470 feet. Using the same formula, (375 ÷ 750) + (200 ÷ 470) = 0.9255, this is less than 1 and will meet NEC standards.

Continuing from the example above…

In the same installation, you also have 110 feet #10 submersible wire from your existing well. Can you add 90 feet wire to achieve 200 feet? What wire gauge?

The answer is yes, and you can use 90 feet #6 wire.

(375 ÷ 750) + (110 ÷ 300) + (90÷750) = 0.9866

Now the decision is whether to buy a brand new 200 feet of #8, or 90 feet of #6. Check the prices for each wire to make a smart decision.