Marina Power supplies for slips

[alphabraxon]

Im doing a marina consult/design but dont have a lot of actual marina experience in same. Questions are:
Assuming pedestals on slips are single phase 2 Lines+ Neutral, is

• is 240/120 Volt a requirement or can i go with 208/120
• Main trans will be 480 Volt 3 phase
• dist trans can be 1 phase 240/120 OR 3 phase 208/120
• for larger slips, will definiely go with 3 phase 208/120

Thanks for any advice

 

[charlie b]

Most recreational boats require either a 30 amp, 120 volt receptacle or a 50 amp, 120/240 volt receptacle. If the boat is large enough to have loads that use the higher voltage, odds are that the loads are designed for 240 volts, not for 208 volts. I once did a design evaluation for upgrades to a large marina. I concluded that the appropriate design had a 480 volt, 3-phase source at the head of the pier, and single phase transformers with a 120/240 volt secondary distributed along the pier. That conclusion was based, in part, on a survey I did of boat manufacturers around the world. I didn?t get a large number of responses, but not one single manufacturer said they would accept a single phase 120/208 volt supply. That was not a recent survey, so my information may be outdated.

 

[charlie b]

?for larger slips, will definiely go with 3 phase 208/120

Unless you are dealing with large commercial vessels, such as ferries, tour boats, and fishing boats, they are not likely to have three phase systems on board. If a large boat has a 240 volt oven, and if it's power system is single phase, and if you supply it with 208 volts, then it will only operate at 75% of its heating capacity.

 

[alphabraxon]

Reason for question is

Developer plans to grow to five docks with total 150-200 slips with prob nothing under 25'.

POCO will only provided 480 v 3 phase pad trans. Hence my ? about 240 or 208. 3 phase 240/120V is mid tapped so no good for 120 volt loads required.

So will go with 480 v 3 phase panel w 2 pole branch breakers to feed required number of 240/120v 1 phase dist transformer on each dock.

the end of larger docks are slated for 100'+ boats. I belive these would use a self contained MDU which incorporates 50kVA+ 3 phase trans and all necesary plug ins, meter etc. these i would feed with dedicated 3 phase power supply direct from 480 v panel.

Your input is appreciatted.

 

[augie47]

I think you may find the FPN at 555.19(A)(3) {'08 Code} interesting.