Please Check my math

[Gac66610]

I'm running a 60a sub-panel to a detached building, approximately 310 ft away from panel
my calculations are showing me i need a 2/0 AL
have not done this type of calculating for some time.

 

[augie47]

You might find this useful....
http://www.mikeholt.com/documents/freestuff/Copy_of_voltage_drop_calculations_by_Bill_Bamford.xls

if I plugged in correctly, a #2 AL would be sufficient

 

[kwired]

What is voltage, load and acceptable level of voltage drop?

 

[Gac66610]

why you need that ... J/K
guess it would be better to have ALL the info

240v 310ft VD is what 3.6%? just a few lights (8) and a few receptacles for battery chargers for ATV s

add:60w lamps probably dont even need 60a to run all this

 

[kwired]

why you need that ... J/K
guess it would be better to have ALL the info

240v 310ft VD is what 3.6%? just a few lights (8) and a few receptacles for battery chargers for ATV s

You still did not give us the load - that makes all the difference in the world on the voltage drop. Just because you have a 60 amp panel does not mean you have 60 amps of load.

 

[Gac66610]

There is no load to say, thats why I was just figuring the 60a as the load, as a non continuous load just to making sure it was covered

 

[Dennis Alwon]

Voltage drop is based on the load. If you anticipate needing a 100 amps then you can figure VD based on that but if you only need 60 amps it makes a difference in the calculations.

 

[Dennis Alwon]

Here is an online VD calculator. This may help you understand.

 

[Gac66610]

Here is an online VD calculator. This may help you understand.

thanks to you and augie for the tools, greatly needed and appreciated :thumbsup:
and i understand that the load is needed for calculation, i just dont know what they might be plugging in, could be just a radio, or a 30a 240v compressor, i just dont know sorry :happysad:
all i want to do is make sure i have atleast 60a being pushed by 240v at the ready, 2" PVC is run so if they need more can always pull in larger wire

 

[Little Bill]

thanks to you and augie for the tools, greatly needed and appreciated :thumbsup:
and i understand that the load is needed for calculation, i just dont know what they might be plugging in, could be just a radio, or a 30a 240v compressor, i just dont know sorry :happysad:
all i want to do is make sure i have atleast 60a being pushed by 240v at the ready, 2" PVC is run so if they need more can always pull in larger wire

I would just use between 48-60V in your calculations and that should get you close to your needs. That is, if the loads don't exceed 60A. If they do, your sub panel is too small to start with. Just my opinion.

 

[ActionDave]

My opinion- I would not run 2/0AL for a 60A feed to a shed 310' away unless there were a specific load in mind.

I would, ditch the voltage drop calculator, use 2-2-4-6 USE (mobile home feeder cable is what we call it) and call it a day.

 

[ptonsparky]

My opinion- I would not run 2/0AL for a 60A feed to a shed 310' away unless there were a specific load in mind.

I would, ditch the voltage drop calculator, use 2-2-4-6 USE (mobile home feeder cable is what we call it) and call it a day.

I agree, and depending on your code cycle you could just use the 2-2-4.

If you have decided a 60 amp panel is big enough, what size wire is the max you can put in the lugs? You can future proof it a bit by putting it in 2" pvc (we can use DB conduit), but other than that just let your customer know that he will have some light flicker at higher currents. If he wants bigger, let him have it. VD for these small sheds can be overthought.