Question: My boat only gets 200v from dock box

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Codger2

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Oct 11, 2007
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Vessel Name
Circuit Breaker
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2021..22' Duffy Cuddy cabin
My boat is only receiving 200 volts & 50amps from the dock. My ACs run on 220 & I'm wondering if this is hurting the units. Some on my dock day it is! :confused:
 

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They could be feeding them from a 208 panel. Only way to know for sure is to find the panel/transformer that's feeding the dock. You can check with others around you and see if they are seeing a similar voltage. As a last resort you can get a transformer to buck the line voltage up to what you need.
 
200 volts isn't good for a 220V air conditioner compressor. As noted above some wiring schemes give 208V which is ok but marginal.


As noted above, confirm the accuracy of your meter. Then check the voltage at the head of the dock to see if the problem is small wiring. Not much you can do for either the 208V wiring scheme or small wiring resulting in a big voltage drop at the end of the dock.


David
 
I notice the lower voltage because the digital thermostat controllers play up and flash if the voltage is too low. Luckily I have step up transformers to get the power back up to a nominal 220-240VAC. I take more care now to check it before I power up. Most dock hands think 50amps is 50amps so I connect up and check the meters first.
 
Not uncommon to have docks wired from a 208V source. It can be lived with if everything with a motor (AC's, fridges, pumps) starts ok. Do double check with another meter and if true go complain a little bit. Someone cheaped out when they wired the dock, saved money on a transformer.
 
My boat is only receiving 200 volts & 50amps from the dock. My ACs run on 220 & I'm wondering if this is hurting the units. Some on my dock day it is! :confused:

It might actually be worse than you think.

If your AC units are single phase they are rated for 240 Volts not 220.

You might be OK though, as some of that stuff is rated for 208-240 volts.

Might check the nameplate.

As others have posted most docks I have seen are fed using 208 volt three phase service, so you would get 208 volts
 
Not uncommon to have docks wired from a 208V source. It can be lived with if everything with a motor (AC's, fridges, pumps) starts ok. Do double check with another meter and if true go complain a little bit. Someone cheaped out when they wired the dock, saved money on a transformer.

Agree; note this issue on Active Captain, etc. This practice needs to stop.:banghead: Your primary alternative, if you insist on using that marina, is install an input isolation transformer, with an input LOW LINE switchable tap.
 
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