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Old 01-01-2012, 14:45   #136
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Re: Neighbor dumping raw AC into water?...what to do?

Marina installations in the US typically get a 2-phase 440V feed to halfway the dock where a transformer is located. From there, each individual power post is wired with:

green - ground
white - neutral
black - 120V L1
red - 120V L2

120V is available between neutral + L1 or neutral + L2.
240V is available between L1 and L2.

So red is a standard color for the 2nd phase in 240V.

With my Victron isolation transformer, I prefer to take ground + L1 + L2. If there is no 240V, I will take ground + L1 + neutral and jumper my transformer to double it to 240V; the Victron always outputs 240V, regardless of 120/240 input. This is another advantage of the Victron transformer.

cheers,
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Old 01-01-2012, 15:13   #137
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Re: Neighbor dumping raw AC into water?...what to do?

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Originally Posted by sdowney717 View Post
The clamp meter is detecting current imbalance, so a RCD or GFCI WILL trip if it detects the imbalance. GFCI has a 5 milliamp leakage trip point.

ELCI trips at 30 milliamps, which one do you think is going to protect better.
Introducing the ELCI

However would either of these protect the boat from AC stray current corrosion ?
Is say 4 milliamp current flow enough to initiate corrosion?

No, unless it trips, an I suspect rate of corrosion would be directly proportional to current flow.
Our marina here has 60mA /60mS trigger RCD's on berth power points. Seems high to me but with damp salty air around any lower probably isn't practicle.

As an aside.
An isolating tranny (inductive) on the 240V marina supply will not help you with a DC fault on YOUR OWN boat.
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Old 01-01-2012, 16:31   #138
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Re: Neighbor dumping raw AC into water?...what to do?

I am not going to get into a long discussion about galvanic corrosion but I will offer a link to a comprehensive article i wrote about testing your AC shore system for anyone who would like to read up on this complicated subject. Project Boat Zen - Checking your shore Power System

In the end solving any problem like this is a matter of systematically troubleshooting till you eliminate all the causes. More often then not the problem is really the result of more than 1 failure. It is detective work and has to be approached in that mater or you are just throwing darts with a blindfold on. There have been many good suggestions here in this thread and other I read on the subject but in the end you just have to test your way through the problem till you eliminate all the problems.
This is why I recommended he contact someone who will have the right equipment to properly test through the problem. A simple volt meter alone is not likely to tell you what you need to know.
Seems like the OP bailed and I think that is just as well I would not want him as my slip neighbor myself!
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Old 01-01-2012, 16:49   #139
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Re: Neighbor dumping raw AC into water?...what to do?

I stopped reading this thread but would like to go to your question about who is responsible. That is a question for a lawyer. The facts are never exactly the same. It seems you are angry and don't feel you should have to do anything. It seems like it would fall under the area of negligence. But there is also assumption of the risk and this is a known risk at marinas.

Get all the facts first. Then find a lawyer that is remotely familiar with this type of situation. You always take legal action against everyone or they blame the person not in court. But have the lawyer send a letter to all parties that may be brought up in a legal dispute. That would include the marina owner/owners.

If you owned a marina and liked getting your check and then found out you may have to give up some of that money you would be upset. Then call the manager and it all rolls downhill. If it works that way you do not even need to go to court.

You said you tested all the boats. That is trespassing if you did not get permission. Be careful when you bring up the law. It cuts both ways.

I find that being nice does more good than anything. I start off nice most of the time and then get less nice. As soon as they seem to work with me I get nice again. It helps people to understand that if we work together it is better for everyone.

Good luck
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Old 01-01-2012, 19:18   #140
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Re: Neighbor dumping raw AC into water?...what to do?

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Originally Posted by s/v Jedi View Post
Marina installations in the US typically get a 2-phase 440V feed to halfway the dock where a transformer is located....
So red is a standard color for the 2nd phase in 240V.
This thread is so full of misinformation In the US, we use 3-phase and single phase power distribution. The power to the dock might be 120v or 240v but it is single phase, not 2 phase, although it is commonly called split-phase because the feed is from a single transformer winding that is center tapped to create 2 120v legs from a single 240v winding. It is not the same as 2 phase. There is such a thing as 2 phase power distribution but it is rarely used.

Eric
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Old 01-01-2012, 19:24   #141
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Re: Neighbor dumping raw AC into water?...what to do?

Quote:
Originally Posted by fairbank56 View Post
This thread is so full of misinformation In the US, we use 3-phase and single phase power distribution. The power to the dock might be 120v or 240v but it is single phase, not 2 phase, although it is commonly called split-phase because the feed is from a single transformer winding that is center tapped to create 2 120v legs from a single 240v winding. It is not the same as 2 phase. There is such a thing as 2 phase power distribution but it is rarely used.

Eric
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Old 01-01-2012, 19:52   #142
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Originally Posted by hummingway
I agree this has been a very informative thread but would ask that people lay off the OP. Should he return and wish to participate in CF then I would hope we'd welcome him.
Should he return, maybe next time he can begin by specifying the exact advice he is willing to listen to prior to asking a question. This will no doubt save him a great deal of the type of frustration he's articulated in this thread.

This could be a whole new type of discourse for Cruisers' Forum. You begin a thread by stating, "Here's the answer I want to hear...." and then ask a pertinent question afterwards.
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Old 01-01-2012, 20:00   #143
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Talking Re: Neighbor dumping raw AC into water?...what to do?

Quote:
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Should he return, maybe next time he can begin by specifying the exact advice he is willing to listen to prior to asking a question. This will no doubt save him a great deal of the type of frustration he's articulated in this thread.

This could be a whole new type of discourse for Cruisers' Forum. You begin a thread by stating, "Here's the answer I want to hear...." and then ask a pertinent question afterwards.
Or to provide even more entertainment one could post an answer and have members try to come up with questions. A few more months to sailing season. lol
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Old 01-01-2012, 21:07   #144
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Quote:
Originally Posted by Bash

Should he return, maybe next time he can begin by specifying the exact advice he is willing to listen to prior to asking a question. This will no doubt save him a great deal of the type of frustration he's articulated in this thread.

This could be a whole new type of discourse for Cruisers' Forum. You begin a thread by stating, "Here's the answer I want to hear...." and then ask a pertinent question afterwards.
Yeah, but then we would all say, "Oh, my dear! If that is the answer you are looking for then your question is all wrong!" Then we would spend 5 pages arguing about what the question should be.

Sounds like fun! We should try it.
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Old 01-01-2012, 21:10   #145
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Re: Neighbor dumping raw AC into water?...what to do?

Yes, I'm blonde, but not that blonde. Yes the dock outlets are wired single phase. However all commercial power in the us above a bare minimum load is 3 phase. Thats what the power companies provide to commercial buildings, and what the power companys distribute across the country. All the marinas I've stayed in have had 3 phase power. A single hot phase of three phase is 120V to neutral.

Electrical engineers love 3 phase as its less expensive to run then single phase for the same load. Smaller conductors and smaller bus bars in panels, etc. The wily electrical engineer will then divide the individual phases equally between all the slips with the hope of having a balanced load back to the power co.

BTW there is NO 2 phase power from the power co, not in the US anyway. Residential is single phase 240V/120 with a center tap to get 120V on each leg to center (neutral) and 240V between the two legs. Each leg being 180 degrees out of phase from the other. Three phase power be it 208V or 460V has the phases 120 degrees apart.
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Old 01-01-2012, 21:19   #146
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Re: Neighbor dumping raw AC into water?...what to do?

Quote:
Originally Posted by sailorchic34 View Post
Residential is single phase 240V/120 with a center tap to get 120V on each leg to center (neutral) and 240V between the two legs. Each leg being 180 degrees out of phase from the other.
Or called split phase.
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Old 01-01-2012, 21:26   #147
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Re: Neighbor dumping raw AC into water?...what to do?

Quote:
Originally Posted by s/v Jedi View Post
Marina installations in the US typically get a 2-phase 440V feed to halfway the dock where a transformer is located
Quote:
Originally Posted by fairbank56 View Post
This thread is so full of misinformation In the US, we use 3-phase and single phase power distribution. The power to the dock might be 120v or 240v but it is single phase, not 2 phase, although it is commonly called split-phase because the feed is from a single transformer winding that is center tapped to create 2 120v legs from a single 240v winding. It is not the same as 2 phase. There is such a thing as 2 phase power distribution but it is rarely used.

Eric
I believe Nick is referring to marinas that feed 2 legs of a 3 phase to a dock for 208v.
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Old 01-01-2012, 21:41   #148
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Re: Neighbor dumping raw AC into water?...what to do?

Yes 240V single phase could be called split phase too. Hum... Though 2 legs from 480V (sometimes called 460V) will give you 277V, not 208V. 277V's is used for lighting, including dock lighting in many cases. Its what those fun loving electrical engineers love to do. BTW 208V/ 3 phase is used for light commercial/condos in many cases. Most larger commercial installations would be 480V/ 3 phase.

BTW, I'm a mechanical engineer, not electrical. But having worked for and with electrical engineers for 30+ years some of their knowledge rubbed off on me...
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Old 01-01-2012, 22:58   #149
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Re: Neighbor dumping raw AC into water?...what to do?

Oops, I screwed up.. 277V is 480V/3p leg to neutral, not leg to leg. You get 480V leg to leg. I do have blonde moments. I refuse to call them grey moments ;-) Odds are the marinas are either 208V/120V 3 phase as thats easy to get. Or for larger marinas 480V three phase with a step down transformers to get the 120V for each 100 ish slips. 240V single phase is generally limited to 200-300 amps.

With a typical 30 amp service to each slip, its not going to take many slips to exceed a single phase service amp capacity. Sure there is Diversity, but even allowing an average 8-10 amps per slip the total amp load per 100 slips is 800-1000 amps. That's going to be served by 3 phase folks.

Most docks have one or more big square boxes that hum. Thats your step down transformer for X number of slips. ;-).

BTW 208V 3 phase is used alot for 120V power as its easy to do. Just 208V /sqrt 3, which gives you 120V.. Tada.

Sorry for the thread drift....
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Old 02-01-2012, 03:47   #150
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Re: Neighbor dumping raw AC into water?...what to do?

Quote:
Originally Posted by fairbank56 View Post
This thread is so full of misinformation In the US, we use 3-phase and single phase power distribution. The power to the dock might be 120v or 240v but it is single phase, not 2 phase
Quote:
Originally Posted by Lancerbye View Post
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Quote:
Originally Posted by DotDun View Post
I believe Nick is referring to marinas that feed 2 legs of a 3 phase to a dock for 208v.
Some understand it It's amazing, isn't it I wonder who of all participating in this thread are licensed commercial electricians. I am, did the 4 years of study, passed exams, got the paper, went on to electronics after that.

Anyways, 120,208,220,240,277,380,440,460,480 are all low voltages (less than 1 kV is still low voltage) in use somewhere for something. What I was talking about is 440V 3-phase which is from the time a center tap gave 220V. Today, it has become 480V with 240V from the center tap but it is feeding the same equipment (like you put 120V into your 110V appliances). In the EU things went from 220V to 230V in the same way... all to get more power through the same wires or to run things a bit cooler.

So yes Eric, you are right that it is 3-phase. 3-phase 440V. But see, I am right too, because I can pick 2 phases out of those three and feed that to a transformer halfway a dock. Using 2 out of the 3 phases is common practice, any commercial electrician deals with this all the time. My error was to assume familiarity with commercial power rather than just domestic power.

It is only on the secondary side of the transformer that we come to the familiar 120-0-120 single phase (also called split-phase) systems. The "0" is a center tap again (hence the phase is split) so that both 120V feeds are shifted 180 degrees. For wiring, these 120-0-120 power feeds are called L1-0-L2 and colors are black-white-red.

In the EU there is no need for this silly setup because the voltage is 230V already. The EU colors are blue for neutral and brown for the "phase" which is what the live is called there. Green with yellow stripe is ground (the yellow stripe because solid green was used in the past for something else) and black is a switched phase (like between lamp and switch).

120/240V single phase feed to docks??!! Come on now, I have never seen a commercial marina with single phase feed to docks. Big docks even have full 3-phase wiring with true substations halfway the docks. This jungle marina here in Panama even has 3-phase connections available for boats (okay, only on the mega-yacht dock).

cheers,
Nick.
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