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Old 14-02-2015, 03:58   #76
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Re: Reverse Polarity

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Originally Posted by mrm View Post
No, I am not slanting anything. I simply present, for enlightenment (p.i.) of readers, how it looks in Europe. I admit I used images found in catalogues of local online distributors, but I can take similar pics myself if you like. It won't change the message though.

For an engineer, you, Sir, are quite rude. Next time, before you accuse me publicly of slanting facts, please do your own research.

As a general remark, this thread drifted a lot from the OP question, but, at least for me, was very informative and, at times, eye opening. For example I would never have thought, that bulb sockets with metal shell being part of the circuit could ever be allowed on consumer market in devices operating on live AC. In my area, such designs are restricted to low voltage devices.

Such a bulb socket would be illegal in Europe
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Old 14-02-2015, 04:04   #77
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Re: Reverse Polarity

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Originally Posted by FlyingCloud1937 View Post
Yep, of course i meant mA, as we all know 15 mV could not carry enough ampers to kill you.

In the US Class A GFCI's have a 5mA nominal rating, for residential wet areas,
1.no trip below 4mA (no load)
2.must trip at 6mA (no load)
3.no trip below 4mA (with load) at rated voltage
4.must trip at 6mA (with load) at rated voltage
5.must trip with 2 ohm grounded neutral
6.must trip within 25 ms with a 500 ohm fault
7.must trip with test button at +10/-15% rated voltage
8.must not trip with noise test of GFCI Standard
9.calibration test at +10/-15% rated voltage
lloyd


You might look at the spec of ABYC whole boat GLCI specs. There are not 5mA disconnects.

US specs are for essentially wet areas. European regs will not allow sockets in wet areas. ( close to sinks baths etc )

The 5ma was chosen as the limit where you can still release your muscles. The 30 mA is set at the insert of heart fibrillation. Both devices protect from death
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Old 14-02-2015, 04:07   #78
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Re: Reverse Polarity

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Originally Posted by Blue Stocking View Post
A lamp bulb is basically a resistance coil, so line/neutral is not that important, It is important with other electrical devices which have chassis grounds for instance. I stopped reading all the posts when it got screwy, but did anyone tell him if he is sharing the pedestal with another boat, it could be a polarity problem on the other boat feeding the neutral. Sorted this out in the boatyard just yesterday.


Nope chassis grounds age connected to the protective earth wire the neutral is never directly connected to chassis ground within the appliance.

Let's get the understanding between protective earth and neutral right.

( leaving aside the issues of establishing neutral I'm the first place )
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Old 14-02-2015, 04:11   #79
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Re: Reverse Polarity

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Originally Posted by FlyingCloud1937 View Post
You are a very foolish...man/woman!

Not because of what you preach....

But, because you don't understand, what you preach????

But, you are right in your own mind, because someone else, confirmed that to you.

But, were they right?

Yes, it must be true, because that is what I believe!!!

the poet
K_V_B is quite right. No boat AC wiring should become unsafe merely because of reverse polarity. If ABYC allows that then all such boats should be legally confined to the coastal waters of the US and forbidden to travel any further afield.

( of course if you follow current /latest ABYC practice your boat isn't unsafe )


Dave
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Old 14-02-2015, 07:13   #80
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Re: Reverse Polarity

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Old 14-02-2015, 07:53   #81
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Re: Reverse Polarity

The only reason we're having a debate on standards is because KVB said something that was incorrect, and then tried to reconfigure the conversation to try and make what he said correct.

The codes are what they are, and they're both pretty safe from what I can tell, if followed.

If your boat indicates a polarity issue, you'd better pay attention to it.
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Old 14-02-2015, 08:51   #82
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Re: Reverse Polarity

On my old US boat factory wiring there are two bus bars near each other. One has all green bonding wires and green AC safety grounds. The other has all DC ground wires.

There is a jumper between the two bus bars and a large wire connecting all of this to the engine block. So bonding, green AC safety, and DC ground all connected together.

White AC neutral goes to the shore AC neutral only. And I assume is connected to earth ground somewhere out there.

The differing standards between EU and US is difficult to understand in this discussion. Primarily, I feel, because of misuse or misunderstanding of the terminology used. Wire color, neutral, safety ground, hot, floating, etc.

Edit..... Just splashed after a month on the hard. Had a reverse polarity light on the hard. Back on the hook but that's why I read this thread. Probably wait til next shore power hookup to try and figure it out.
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Old 14-02-2015, 10:12   #83
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Re: Reverse Polarity

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Originally Posted by four winds View Post
On my old US boat factory wiring there are two bus bars near each other. One has all green bonding wires and green AC safety grounds. The other has all DC ground wires.

There is a jumper between the two bus bars and a large wire connecting all of this to the engine block. So bonding, green AC safety, and DC ground all connected together.

White AC neutral goes to the shore AC neutral only. And I assume is connected to earth ground somewhere out there.

The differing standards between EU and US is difficult to understand in this discussion. Primarily, I feel, because of misuse or misunderstanding of the terminology used. Wire color, neutral, safety ground, hot, floating, etc.

Edit..... Just splashed after a month on the hard. Had a reverse polarity light on the hard. Back on the hook but that's why I read this thread. Probably wait til next shore power hookup to try and figure it out.
Forgetting the issues raised on US vs European standards, your boat would not be manufactured in the US today by any major boatbuilder with the neutral and earth ground bus bars connected on the boat. The earth ground would be connected to the main DC ground only (separate bar or engine block usually). The neutral would not be connected to any DC negative point. ABYC standards specifically require this.

In your situation if you had reverse polarity there is the definite risk in that your DC negative system, and any connections to it, would be hot.
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Old 14-02-2015, 10:41   #84
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Re: Reverse Polarity

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Originally Posted by four winds View Post
On my old US boat factory wiring there are two bus bars near each other. One has all green bonding wires and green AC safety grounds. The other has all DC ground wires.

There is a jumper between the two bus bars and a large wire connecting all of this to the engine block. So bonding, green AC safety, and DC ground all connected together.

White AC neutral goes to the shore AC neutral only. And I assume is connected to earth ground somewhere out there.
I read this as the AC earth (green wire) and DC negative are connected together. In North America this is proper. Nowhere do I read that the AC neutral is connected to DC negative on the boat.
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Old 14-02-2015, 10:43   #85
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Re: Reverse Polarity

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Originally Posted by goboatingnow View Post
If you own a boat with AC neutral and DC ground connected I recommend you get that fixed fast.

ABYC requires protective earth and DC neutral connected.

I trad these posts by predominantly US posters arguing things they simply don't understand. Or simply arguing the " code " is right.

Reverse polarity because of deficiencies in US electrical codes has some issues.

Bit No boat should become " unsafe " merely because the live and neutral ate swopped.

Furthermore mention by posters of reversing investors or chargers and causing damage is pure fiction

I'm familiar with NEC and ABYC.

THE. FACT is that if you leave the confines of your beloved US electrical code YOU WILL come across situations where neutral is either floating symmetrically or at elevated potential. You should therefore make sure your onboard systems do not become unsafe , if they are therefore not unsafe , reverse polarity if of little consequence

Dave

Dave
Dave, I do appreciate that it would be absolutely fantastic if reverse polarity would not cause a risky situation, whether in the US or in Europe or at the South Pole. The fact of the matter is, right, wrong, or indifferent, because of the way 95% (or some such number between 90 and 99) of US boats are currently wired (pun intended) reverse polarity can cause a very hazardous situation. Just because anyone thinks it is inferior is not germane to this discussion. It is just the way it is.

You and others definitely feel strongly about this. I am not disagreeing with your concerns. But you are preaching (not a negative (pun intended) comment) to the wrong crowd. You should consider taking this up with the American NEC and ABYC standards boards and initiate a healthy discussion with the folks there. You would certainly get in to the middle of some heated discussions there. And if they were to change the standards, then over the course of the next several decades, the entire fleet of old boats that are wired to current standards, would either die or be scrapped because they are dangerous.

P.S. the US standards or the European standards are not "beloved" by me and I have not detected that from most of the posts here. But it is the entire system that is important because if one device is not designed for whichever other system then you potentially (pun intended) have a problem. Not right or wrong, just what is reality out there.

P.S.S. I would have zero qualms in taking my US-standard-wired boat over to Europe and plug in to shore power there, provided no regulatory people did not descend on my boat and red flag it. I would have to address the voltage and frequency issues with the appropriate equipment of course. A voltage transformer would readily handle the voltage difference, but, as necessary, I would have to avoid connecting any device that requires strictly 60Hz. But most sophisticated battery chargers now sold will easily handle European electricity at 230V/50Hz, and lighting doesn't really care. But many electronics might. In this case I would use my inverter off of battery power to provide 60Hz. I would not have a shore power AC grounding conductor but the transformer on the boat would provide it for the boat wiring.

P.S.S.S One gentleman (pun intended) here stated that he plugged in to his family's garage circuit for shore power was sure that it was reverse polarity half of the time. That would be exceedingly odd and definitely not safe or up to code in the US. We still have metal light sockets - right or wrong. And you would have great difficulty selling a house with that setup if an inspection was required. One of the very first, and easiest, tests that home inspectors do is to plug in the inexpensive reverse polarity tester and it would be highlighted in the report. I would be curious though how the polarity was reversed some of the time and not others. That would require some rewiring for half the time and then reversed the rest of the times. Not sure why anyone would do that.
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Old 14-02-2015, 10:48   #86
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Re: Reverse Polarity

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Originally Posted by goboatingnow View Post

Furthermore mention by posters of reversing inverters or chargers and causing damage is pure fiction

Dave
I don't know about that. I assume you are referring to the reversal of the hot and neutral wiring. Inverters internally connect earth (green) and neutral while inverting. If hot and neutral are reversed that means the inverter is connecting earth and hot while inverting. This can't be a good thing.
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Old 14-02-2015, 12:48   #87
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Re: Reverse Polarity

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Originally Posted by mitiempo View Post
I don't know about that. I assume you are referring to the reversal of the hot and neutral wiring. Inverters internally connect earth (green) and neutral while inverting. If hot and neutral are reversed that means the inverter is connecting earth and hot while inverting. This can't be a good thing.
At first blush, I was thinking the same thing but I am not sure after thinking about it more. There are inverters and inverter/chargers. Some inverters and inverter/chargers can be wired so that they pass through shorepower to the main panel AC output breakers. If there is reverse polarity then the reverse polarity will be passed through. I do not know if that would be problem for the inverter.

Any inverter with a pass-through or inverter/charger will have a relay that will bond the neutral and green grounding circuits together when the unit is inverting, but will not bond when it is passing through shorepower AC.

Some inverters are not wired to incoming AC - they are dedicated to their own separate set of outlet breakers - and the neutrals for those have to be separated from the shorepower outlet breakers i.e. they cannot share the same neutral buss as the shorepower breakers do. This can be a tedious job if adding a new inverter, especially since most boats do not have labels on the neutral wires connected to the buss. You have to identify each one by trial and error. A clamp-on AC ammeter makes this a much easier job.

If the inverter will only be powered a completely isolated outlet or other devices that are not a part of the shorepower AC system, then there is no issue with isolating neutrals as they are not shared.

So if there is a pass through of shore power from a hardwired inverter or a inverter/charger then the reverse polarity will be passed through and the neutral and the grounding wire will not be bonded at the inverter. When inverting the incoming lines (with the reverse polarity) will be interrupted and the inverter will produce correctly polarized AC on the AC output side.

I hope this makes sense.
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Old 14-02-2015, 12:53   #88
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Installing land appliances on boats

One thing I have been intending to add: appliances not designed for marine use often have the neutral and ground bonded within the unit. This can cause difficulties when checking polarity and AC wiring on boats.

A good example is putting a regular refrigerator or microwave on to a boat. I have had to often take the case off of the item, or otherwise get into the AC incoming wiring, and disconnect the neutral from the case. If you have reverse polarity then the appliance case would be hot.

So if you are installing land use appliances, put your ohmmeter on the neutral and the ground plug and see if they are connected internally.

Another reason European standards are far, far superior than US LOL.
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Old 14-02-2015, 13:25   #89
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Re: Reverse Polarity

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Originally Posted by mitiempo View Post
I don't know about that. I assume you are referring to the reversal of the hot and neutral wiring. Inverters internally connect earth (green) and neutral while inverting. If hot and neutral are reversed that means the inverter is connecting earth and hot while inverting. This can't be a good thing.

You know there are inverters being sold with German "schuko" receptacles, which are reversible...
From the point of view of the inverter the wire that is connected to earth will always be "neutral". That's how neutral is established in the first place. If you swap leads on whatever you connect to it, you will indeed see live where you expect neutral, and vice versa, but the inverter itself will work fine.


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Old 14-02-2015, 13:28   #90
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Re: Reverse Polarity

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Originally Posted by exMaggieDrum View Post
P.S.S.S One gentleman (pun intended) here stated that he plugged in to his family's garage circuit for shore power was sure that it was reverse polarity half of the time. That would be exceedingly odd and definitely not safe or up to code in the US. We still have metal light sockets - right or wrong. And you would have great difficulty selling a house with that setup if an inspection was required. One of the very first, and easiest, tests that home inspectors do is to plug in the inexpensive reverse polarity tester and it would be highlighted in the report. I would be curious though how the polarity was reversed some of the time and not others. That would require some rewiring for half the time and then reversed the rest of the times. Not sure why anyone would do that.

Most of Europe uses unpolarized sockets and plugs. That is the reason I assume that our boat sees L and N reversed regularly, as the way the plug is inserted is rather random.


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