voltage drop

[ugabulldog]

Voltage drop was calculated for #10 wire and I am very close (right at) to the max run so I think I will need to size down to #8 wire running 390 ft. to well,....wire in well is 240' of #10 wire, is this ok to mix 8 & 10 to compensate for volt drop?

 

[Valveman]

Actually having the maximum recommended cable length is a good thing. It makes a natural soft starter. #10 wire will go 630' with a 1 HP motor. It doesn't hurt anything to start with #8, except that it won't give you the soft start like 630' of #10 will do.

"Reduced-voltage starters may not be required if the maximum recommended cable length is used. With maximum recommended cable length there is a 5% voltage drop in the cable at running amps, resulting in about 20% reduction in starting current and about 36% reduction in starting torque compared to having rated voltage at the motor. This may be enough reduction in starting current so that reduced-voltage starters are not required."

Heres the link;
http://www.franklin-electric.com/aim-manual/page-36.aspx

 

[Sponsor]

 

[Ballvalve]

I have almost the exact same setup and pump is happy for several years and runs on 239 volts after start up. I may even have a 1.5hp motor on it.

But where is the control box? at the beginning of the run, or at the well head?

 

[Valveman]

I don't think it will make much difference where the control box is. But I think the starting torque would be less the further away the control box is.

 

[ugabulldog]

Actually having the maximum recommended cable length is a good thing. It makes a natural soft starter. #10 wire will go 630' with a 1 HP motor. It doesn't hurt anything to start with #8, except that it won't give you the soft start like 630' of #10 will do.

"Reduced-voltage starters may not be required if the maximum recommended cable length is used. With maximum recommended cable length there is a 5% voltage drop in the cable at running amps, resulting in about 20% reduction in starting current and about 36% reduction in starting torque compared to having rated voltage at the motor. This may be enough reduction in starting current so that reduced-voltage starters are not required."

Heres the link;
http://www.franklin-electric.com/aim-manual/page-36.aspx

That is my problem,...I am a little over 630', by a few feet, so I should go with #8, in fear of burning pump up faster, correct?

 

[Ballvalve]

You can mix wire sizes. But the charts have much leeway in them. Dont sweat a few feet.

 

[ugabulldog]

control box is at the well head, does this make a differnce ballvalve or anyone??

 

[Justwater]

it's fine, no worries.