Dock Electric

[bigbearelec]

I have a job that the dock is 550' from the closest electrical panel and the contractor wants to install a dock tower. We are trying to design it right now and we keep on getting hung up with the Voltage Drop. Is there a way we can do this without run 250KCmil for at 50A dock tower ??? Please I'm interested in good ideas.

 

[infinity]

What are you using as an amp value for the VD calculation? If you want to avoid larger conductors the one option may be step up/step down transformers. What is the available voltage 120/240? 480 with a step down at the end would work as well if that's available.

 

[bigbearelec]

120/240v I was thinking about the transformer but house is in wetlands so was worried about that.

 

[Fred B]

Not sure how he is calculating but the Southwire app indicates for 240V 50A 550 ft and 5% VD use of #2 copper will work. I would not put out onto a dock anything but copper anyway. Even at 3% it is only a 1/0.

 

[tjdilly]

Not sure how he is calculating but the Southwire app indicates for 240V 50A 550 ft and 5% VD use of #2 copper will work. I would not put out onto a dock anything but copper anyway. Even at 3% it is only a 1/0.

He is getting 250s because he is entering in 120V into the calculation instead of 240V @ 3%VD. Could go like a quarter mile with 250s.

Tell the contractor that voltage drop is calculated using the L-L voltage, not the L-G voltage when you're installing a sub panel.

 

[electrofelon]

You could likely use a lower value than 50 as well. I would probably use 40 as it is unlikely the current would be above that.

 

[tortuga]

120/240v I was thinking about the transformer but house is in wetlands so was worried about that.

You mentioned a dock and a wetland, not related to your question but do take a look at Articles 555, and 682 as you'll run into a bunch of requirements around that.