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Low shore power voltage

Discussion in 'Technical Discussion' started by NYCAP123, Jul 2, 2013.

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  1. Marmot

    Marmot Senior Member

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    Sometimes it just ain't worth asking anymore.
  2. NYCAP123

    NYCAP123 Senior Member

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    I've hit two marinas in a row with low voltage. So I get the feeling this may be more prevelent than we realize. The marina claimed to be supplying 208V, However who knows when they metered it. When we came in, our meters showed 180V. We had trouble running our 5 a/c's. I think they may have had a further voltage drop so they've now added a booster at the pedistal, and it raised the voltage to 190V at the booster and at our meters. At that the a/c's work ok, but when I turn on the booster on the boat dedicated to the a/c's they sound better. So I have an idea of what voltage our a/c's will work at comfortably. I'd love to have 220V but my a/c's can get by on 190V (I'm talking about not straining; want to hear what I can go down to safely).
    Not a lover of fire. Right now we have one booster dedicated to the Galley and one for the a/c's. What I'm curious about is whether it's necessary to put another booster on the main feed to the entire vessel or at what voltage point you think a boat or equipment would be in danger.

    BTW, in casse you didn't catch it, electric is not my strong suit. Looking to learn.
  3. chesapeake46

    chesapeake46 Senior Member

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    180, 190 whatever it takes.... Mr. Mom fans out there

    Sorry,.. if the marina is supplying you with 190 volts after their boosting transformer, what is the voltage after YOUR boosting transformer under load ?
  4. chesapeake46

    chesapeake46 Senior Member

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    It'd be interesting to know the " no load" voltage too.
  5. NYCAP123

    NYCAP123 Senior Member

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    Since the booster is supposed to boost about 10% I'd say our a/c's are seeing about 209V, which is normal, but I wasn't able to meter what they were receiving. With our dedicated booster off they were getting 190V and seemed to be working ok.
  6. NYCAP123

    NYCAP123 Senior Member

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    I have absolute faith in the meter and the guy using it. Lot's of untility experience for both. Plus the ship's meter and his verified each other.
  7. Capt Ralph

    Capt Ralph Senior Member

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    You have to realize that to make voltage, current draw goes up. So if your at 180/190vac drawing 50 amps, your boost transformer ramps up to 200/220vac, current draw could go up over 60amps. And, That IsoBoost xfrmr is getting hot.
    AND, somebody else on the dock is getting less juice if your drawing all the current.
    It's always better not to be on the end of the dock.

    Another note; Ive noticed some off-brand handheld dvm's on the market that are in use. They can read RMS and P/P. Some errors could be the meter not set up correctly and you think your reading the low voltage. Please ensure your reading P/P. The old analog meters on board are crude but usually close enough to give the experienced owner an idea.

    That 208vac comment is from the Y transformers you see half way down the docks lately. 208vac is fine to use, but your auto IsoBoost will still kick in and ramp up the vac and current. popped breakers, people think there is a problem but it's induced over current. Ugly circle.

    Bottom line;
    There are a lot of docks and marinas out there with great electric problems. I wish there was a data base available for people to update & consult to.
    There are allot of boats out there that have problems also.
    Put these two together and there is going to be confusion and finger pointing.

    If your a transit and you don't like the vac, report it and protect you boat.
    If your permanent, report it and protect your boat. Your boat is your investment and needs protection, including moving to another dock/marina.
    Word of mouth (and maybe one day a data base) may provide enough pressure to the dock owners to improve their service.
    Also, this data base could be helpful for the dock owners to identify problem boats, they are out there; I have refused to work on some of them.
  8. NYCAP123

    NYCAP123 Senior Member

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  9. Capt Ralph

    Capt Ralph Senior Member

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  10. Pascal

    Pascal Senior Member

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    208v is the bare minimum you want to run...190v is way too low and asking for problems... If my marina was only providing 190v I d be looking for another one, which obviously any not be feasible

    I m not sure I understand how th second transformer is only used by the galley... That doesn't make much sense. As mentioned Earlier in the thread the earlier hatts like mine do not have transformers but from what I have seen, there should be two and they are between the inlets and the panels which makes it impossible to feed only the galley.
  11. NYCAP123

    NYCAP123 Senior Member

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    I guess these were added after market then, and I'm glad they were or I'd be buying them now. Evidently 190V is usable although 208V is good and 220V ideal. It works. The power feeds from the pedistal to the panel, and then out to the boat. The boosters are installed after the panel in the lines that feeds the a/c and the galley.

    BTW, to answer an earlier question, with the a/c's and galley fridge on we draw about 20 amps.
  12. Capt J

    Capt J Senior Member

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    Keep in mind he's in an area where Hurricane sandy whipped through and flooded everything for a week. So I'm assuming that all of these marina's wiring, transformers and etc had been sitting submerged in saltwater for a week. My guess is the electric company's grid isn't totally up to snuff yet, but within the lower end of acceptable specs. The marina's wiring got stressed with saltwater, the transformers wiped out, and they probably haven't gotten around to changing them yet. This is just a hunch.

    NYCAP, you'd probably be alright with what you've got. I don't understand why they put a voltage transformer for the galley, the stove and oven don't care what voltage you're feeding them (within reason). They'll still work whether 208 or 188. The microwave probably had an issue.
  13. Capt J

    Capt J Senior Member

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    You're very familiar with these Hatteras' and so am I. What I am guessing is they wired 1 transformer to Source 1, the other transformer to Source 2 on the panel, then left Source 3 without a transformer. That was the electricians poor way of telling NYCAP what's getting electric. Since Source 3 has the water heater, battery charger, air compressor and just crude Electrical items they didn't feel a need to split wiring there and install another transformer.

    As to NYCAP, I would run minimal electric on the boat until you leave.....maybe draw no more than 30 total amps at a given time, just out of safety.
  14. NYCAP123

    NYCAP123 Senior Member

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    Full-sized household refridgerator, full size household electric stove & oven, etc. Kitchens draw a lot of juice. I agree it wouldn't need it unless most everything were turned on at once, but since it's there it's ok with me.
  15. NYCAP123

    NYCAP123 Senior Member

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    That's our plan. The boat's in the yard for work. We're not living on it. So a/c, fridge, a couple of lights and not much else. She's drawing about 20 amps with what's running.
  16. jhall767

    jhall767 Senior Member

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    Yes I understand you are trying to learn. There are two major areas of concern I have. It appears this may be an ongoing issue with the locations the boat will be cruising to.

    First of all understand that in order for the voltage to drop from say 208 to 180 or (170) the energy is being used somewhere. Bad connection, bad wires, bad transformer? Who knows But that's a lot of heat in the wiring. To require 3 booster transformers to get it back to "normal" is using a lot more energy. So now we most likely have something cooking in the circuit. Hopefully not on your boat but what ever it is is likely to short out at some point. What is going on with the safety ground (bare wire) in all this circuitry mess? Now you hope that you are running the A/C units at the bare minimum voltage. This means you are at maximum current which is further stressing the wiring in the boat. If you aren't getting the boost you hope you are then you are running even more current through everything. What causes the voltage to be so low? If it is an overstressed grid then does the voltage return to normal as the load drops through the night? Where does that leave the triple boosted voltage?

    Second issue: It doesn't seem like you are checking enough voltages. Maybe you are but not posting them? Since you have 240V appliances and 120V appliances you should have two 120V lines that are 180 degrees out of phase and combine to give you single phase 240V. With 208V power you typically have 3 120V single phase lines that are out of phase by 120 degrees and give you 208V across any two of them. If the marina is boosting the 208V circuit what is that doing to your 120V circuit? You need to check all voltages or you may be replacing a lot of equipment before its time.

    I'm not an electrical engineer (my sister is though) and this is not a comprehensive explanation but think of it this way - Would you run a boat that had any of its major systems jury rigged this way?
  17. NYCAP123

    NYCAP123 Senior Member

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    Obviously there is a problem with the electrical service at these marinas, but that's above my pay grade. They know and I must assume they're working on it or they just don't care. For me though I can hear how hard my appliances are working, in particular the a/c's as they're the biggest draw. At 180V they're working (at the previous marina they shut down so I assume it was less there), and I agree that can't be good for them. But at 190V they sound ok. After getting boosted they sound a little better. From what I've read and understand I should be worried about cooking things if I were getting too much, but these days most appliances can handle too little ok and will simply shut down if it gets too low.

    So I guess it really comes down to:
    God, grant me the serenity to accept the things I cannot change,
    The courage (and knowledge) to change the things I can,
    And wisdom to know the difference.

    If I were staying on the boat I'd probably be using our boosters, but everything seems to be ok with what I'm getting right now. The main concerns I had (and have resolved) are a) whether my meters were accurate and b) was the low voltage a problem with our boat or with the marina. My meters are accurate and my systems are ok. I'm not about to start rewiring the marina.

    I suspect that, as Capt.J mentioned, we may find similar problems in areas hit by Sandy and we may find it at places that just haven't bothered to keep up with their maintenance the last few years. I'd recommend that all boaters confirm their meter's accuracy, and pay attention to the voltage when they go to a different marina. If this is a wide-spread problem a lot of boats may need to add voltage boosters to their equiplrnt list.
  18. Capt J

    Capt J Senior Member

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    If the voltage your getting is as low as you're getting absolutely use your boosters. That is what they are there for and will help your a/c compressors and such run much better.....
  19. NYCAP123

    NYCAP123 Senior Member

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    Between the fact that I'm not on the boat, haven't run them before, and the light load that's on while she's laid up, I'd rather not if they're not needed, and currently they're not. When I turn on electrical equipment that I'm not familiar with it's age nor condition I'd like to hang out with it for a few hours.
  20. Capt J

    Capt J Senior Member

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    I wouldn't be afraid to use them if they look to be in servicable condition on the outside. The reason they were installed was for this situation and to not stress out the a/c compressors and other various items. You should know within 10 minutes whether they're ok or not after turning them on and pulling some amperage through them.