# Marina Voltage Drop



## littlebro (May 19, 2011)

I'm wiring a small marina (22 slips, 2 houseboats, 1 bathroom and some lighting) and having some trouble sizing feeders. The houses are at the end of the dock, about 1000' from the service, and each gets a 100a 120/240 single phase feeder. There will be several pull or junction boxes along the way, and we're thinking of running PVC along the side of the dock, but we'll have to run quadplex overhead from the shore to the dock (to allow greater flexibility for the ramp.) I did a quick VD calc. and figured either 350 aluminum for each or parallel 350 for both (I figured the actual load at around 85a for each house.) Can I run several sets of parallel 1/0 quadplex, then connect them to just one set of 350? Can I run smaller wire for certain portions of the run, calculate the voltage drops individually and just add them together? The biggest quadplex I've found is 4/0.


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## Dennis Alwon (May 9, 2009)

littlebro said:


> Can I run several sets of parallel 1/0 quadplex, then connect them to just one set of 350? Can I run smaller wire for certain portions of the run, calculate the voltage drops individually and just add them together? The biggest quadplex I've found is 4/0.


You sure can- just follow the rules in 300.3(B)(1) and 310.4


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## Rockyd (Apr 22, 2007)

littlebro said:


> I'm wiring a small marina (22 slips, 2 houseboats, 1 bathroom and some lighting) and having some trouble sizing feeders. The houses are at the end of the dock, about 1000' from the service, and each gets a 100a 120/240 single phase feeder. There will be several pull or junction boxes along the way, and we're thinking of running PVC along the side of the dock, but we'll have to run quadplex overhead from the shore to the dock (to allow greater flexibility for the ramp.) I did a quick VD calc. and figured either 350 aluminum for each or parallel 350 for both (I figured the actual load at around 85a for each house.) Can I run several sets of parallel 1/0 quadplex, then connect them to just one set of 350? Can I run smaller wire for certain portions of the run, calculate the voltage drops individually and just add them together? The biggest quadplex I've found is 4/0.


VD = 1.73 x K x I x D = Volts
CM​


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## nitro71 (Sep 17, 2009)

That's a kick ass job! One thing you can check out is the demo for this companies software:

http://www.edreference.com/

I think I used the demo for this one time and it worked really well. Having a hard time remembering if it was this software though.

One other thing I'd think about is what are those house really going to draw for amperage? Calcs err on the side of being very cautious.


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