Voltage drop @ 580 feet

[Tigerracer]

Customer wants to extend feed to a job trailor. Total run is 580 feet so they buried a two inch conduit. They called me today and asked what size wire do they need to be safe for a 100 amp sub panel in the trailor. Wants to use aluminum. Single phase 120/208. Do they need ground wire or just ground rods at the trailor. Thanks

 

[kwired]

What is the load? 100 amp subpanel means very little could only have 5 amps of load or could have 100 amps.

 

[kwired]

Do they need ground wire or just ground rods at the trailor. Thanks

Both............

 

[augie47]

what kwired said !
here is a link to a decent voltage drop calculator...
you can play the numbers
http://www.electrician2.com/calculators/vd_calculator_cond_size.html

as far as the ground wire/rods, it will depend on some particulars such as: (a) one building feeding another ? , (b) what Code cycle, (c) any metallic path bewteen buildings ?

In a majority of situations today you need both.

 

[Tigerracer]

Can't say for sure, but i must assume they will be using some portable heaters, coffee pots, AC, hand power tools and possibly another trailor. What I really need to know is what size wire would hold 100 amps at that distance.

 

[Tigerracer]

Augie, it is from an existing building to a job trailor about four hundred feet away.

 

[augie47]

the formula I provided shows a 4/0 AL with a 100 amp full load would give you about 5% drop. With a 2" conduit I don't think you would want to try and go any larger.