Voltage drop

[guschash]

Where do I find the voltage drop formula. Do I use T310.15(B)(16) or T310.15(B)(7). I have a run of app. 500ft. Top of my head, every 100ft go up a AWG.. Thinking 100amp panel 1 AWG. Thanks for any in-sight. Main panel in the house to the barn. Which is really going it be a basketball court. Building is 60x90 ,all LED lighting,small office,bath room, heated floor,that's it. Not sure what heated floor pulls yet.

Gus

 

[Smart $]

Where do I find the voltage drop formula. Do I use T310.15(B)(16) or T310.15(B)(7). I have a run of app. 500ft. Top of my head, every 100ft go up a AWG.. Thinking 100amp panel 1 AWG. Thanks for any in-sight. Main panel in the house to the barn. Which is really going it be a basketball court. Building is 60x90 ,all LED lighting,small office,bath room, heated floor,that's it. Not sure what heated floor pulls yet.

Gus

Rather than providing one or more formulas for voltage drop, might I suggest using one of the many voltage drop calculators on the web. Here's a link to one:

http://www.electrician2.com/calculators/wireocpd_ver_1.html

BTW, not a recommendation, just one of the many.

Also, a barn (for any purpose other than dwelling) does not qualify for T310.15(B)(7).

 

[ActionDave]

Where do I find the voltage drop formula. Do I use T310.15(B)(16) or T310.15(B)(7). I have a run of app. 500ft. Top of my head, every 100ft go up a AWG.. Thinking 100amp panel 1 AWG. Thanks for any in-sight. Main panel in the house to the barn. Which is really going it be a basketball court. Building is 60x90 ,all LED lighting,small office,bath room, heated floor,that's it. Not sure what heated floor pulls yet.

Gus

It is a rule of thumb to go up one size for every additional 100', but that is not needed very often. Voltage drop is load dependant. If you want to go through the trouble you could do a calculation.

In your case I probably would have no problem using #1AL. The floor heat is the wild card, but it would have to be a whole lot of heat before I would worry about it.

 

[guschash]

Thanks for the replies. Thought because the building was being fed from the house that T310.15(B) could be use?

Thanks again,
Gus

 

[Smart $]

Thanks for the replies. Thought because the building was being fed from the house that T310.15(B)(7) could be use?

Thanks again,
Gus

Sorry to say, no. Has to be a service or feeder supplying a dwelling in its entirety to qualify.