Voltage Drop

[rrrusty]

(Existing)On an underground feed from the pole to the structure with the distance at 735' using Alum direct burial cable sized at 300 kcml with the c/b at the pole at 200A and put on main lugs at the l/c at the structure; What would be the allowable ampacity to carry the structure? My thought was to put a 125A main c/b instead of the lugs in place now,the owner has a 100A going to the main structure as well as a 50A going to a detached garage and wants to add an electric H2O htr and a hot tub; the load calc that I came up with for the main structure is at 86A before he adds the extras; Are my figures and methods off? I had figured that with the distance and v/d that only 125A could be about the max amount; Comments please, Thanks

 

[bennie]

Re: Voltage Drop

I calculate for 125 amps, the drop will be 5.4% of 240=13 volt drop.

 

[rrrusty]

Re: Voltage Drop

Thank you

 

[websparky]

Re: Voltage Drop

the load calc that I came up with for the main structure is at 86A before he adds the extras;

Is this 86A load at 120V or 240V? In other words, are all of the loads single phase-single pole or are some single phase-two pole?

 

[rrrusty]

Re: Voltage Drop

It is on a 240V calc; It has 3- 2pole circuits; Range, dryer, H2O pump Then the rest are 1pole circuits