660ft dock help

[Moosifer]

Any advice on getting power out there?
Residential & salt water 660ft from meter.

2x 3/4hp lift motors (15a 240v) for one lift plus 30a of 120v for battery charger, etc.

Subpanel will be on new fixed non-floating dock with expansion joints in conduit 12" or more above electrical datum line.

Equipment type gfci (gfpe) on shore, quicker trip gfci's on dock.

1. Thoughts on aluminum wire vs copper wire.
2. Thoughts on aluminum wire with copper ground vs copper wire.
3. Thoughts on 480v transformers and smaller wire. Copper or aluminum.

Any help would be appreciated. I have been in some newer commercial dock transformer / distribution panels to replace & correct circuits that were installed with splices below the dock and it looks like there is a lot going on in those panels. So maybe transformers are not cost effective vs bigger wire.

 

[augie47]

There does not appear to be a large enough load to warrant transformers.
Locally the guys would likely use Type W cable (Cu) rather than mess with conduit & expansion joints,

 

[Moosifer]

Thank you

 

[Rick 0920]

I would pull direct burial AL conductors for your shore power panel and protect the panel with a GFCI breaker. Then use Carflex with PVC Clic straps and stainless screws for your branch circuits