Reverse Polarity

[Sailingcouple13]

I had the same problem at my dock at my home. One day the reversed polarity light was on. Turned out that my grounding for the house was failing and using the boat as a ground. Fixed the grounding problem and the stray curent went away. It took the marine electrician no time to determine it was not on the boat. Unplug the shore power problem went away, no polarity issues from generator or inverter.

Move to another Marina.

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[mitiempo]

Originally Posted by K_V_B

No it doesn't.

Not if the boat is properly wired. Appliance makers have stopped making assumptions about which wire is live and which is neutral decades ago. You should do likewise.
Just install a double pole main breaker and RCD and you do t have to worry about reverse polarity. That is what my book about marine electricity tells me anyway...

Actually it certainly can be dangerous.

Most boats have single pole AC breakers for each circuit after the double pole main breaker, only breaking the hot (black) wire. In a reverse polarity situation breaking the black wire, which is no longer hot leaves the circuit live.

[K_V_B]

Originally Posted by mitiempo

Actually it certainly can be dangerous.

Most boats have single pole AC breakers for each circuit after the double pole main breaker, only breaking the hot (black) wire. In a reverse polarity situation breaking the black wire, which is no longer hot leaves the circuit live.

In large parts of the world (all of continental Europe for example) everything that connects to a power outlet has to be designed in a way that the polarity of the power outlet does not matter. If the polarity does matter for your boat than your boat is not properly wired.

[rwidman]

Originally Posted by K_V_B

In large parts of the world (all of continental Europe for example) everything that connects to a power outlet has to be designed in a way that the polarity of the power outlet does not matter. If the polarity does matter for your boat than your boat is not properly wired.

OK, I get it, Europe is way better that the USA. Just remember though, you would all be speaking German today if it wasn't for the Good Ole' USA!

[rwidman]

Originally Posted by mitiempo

Actually it certainly can be dangerous.

Most boats have single pole AC breakers for each circuit after the double pole main breaker, only breaking the hot (black) wire. In a reverse polarity situation breaking the black wire, which is no longer hot leaves the circuit live.

Exactly. And for another example, let's look at the common table lamp. The base of the socket that a person might touch when replacing a bulb is connected to the neutral side of the circuit. Reverse the polarity and that exposed lamp base is now at 120 volts to neutral and ground. Ground being any convenient plumbing fixture or appliance case.

[rwidman]

Originally Posted by K_V_B

......... Appliance makers have stopped making assumptions about which wire is live and which is neutral decades ago..............

That is incorrect and dangerous misinformation.

[goboatingnow]

Originally Posted by rwidman

OK, I get it, Europe is way better that the USA. Just remember though, you would all be speaking German today if it wasn't for the Good Ole' USA!

Thanks.

Unfortunately you were too late all of us In the Eurozone are already doing so. Plough " shares " seem always to win on the end. !!!

Leaving aside jingoism. 230 vac standards tend to be more rigorous then 110 vac. That's just a function of death !!

[goboatingnow]

Originally Posted by rwidman

That is incorrect and dangerous misinformation.

No appliance on the European market meeting the low voltage directive and therefor CE marked would be acceptable if its safety was compromised by reversing the live and neutral.

Dave

[K_V_B]

Originally Posted by rwidman

OK, I get it, Europe is way better that the USA. Just remember though, you would all be speaking German today if it wasn't for the Good Ole' USA!

I am speaking German today... (And it's Poles that liberated my home town...)

[goboatingnow]

Originally Posted by mitiempo

Actually it certainly can be dangerous.



Most boats have single pole AC breakers for each circuit after the double pole main breaker, only breaking the hot (black) wire. In a reverse polarity situation breaking the black wire, which is no longer hot leaves the circuit live.

Firstly a typical single AC breaker is not a safety device. Nor can it be ever regarded as so. Working on a AC circuit by merely " disconnecting " what you " perceive " is the live wire by using a single like breaker is fool hardly in the extreme. Any complement electrician would " isolate " the mains supply. That on my experience means both feed wires are disconnected.

An AC breaker is there to prevent overloads in the circuit , while not optimum it still does that in a reverse situation. ( but obviously it exposes a Reverse hot to ground issue )

If you want to add safety as a consideration, then add a RCD to the circuit. This is a double pole isolator . I welcome ABYCs late arrival to this particular party.

I know of no appliance that is compromised by reverse polarity. References to US ww2 appliances aside.

Dave

[K_V_B]

Originally Posted by rwidman

Exactly. And for another example, let's look at the common table lamp. The base of the socket that a person might touch when replacing a bulb is connected to the neutral side of the circuit. Reverse the polarity and that exposed lamp base is now at 120 volts to neutral and ground. Ground being any convenient plumbing fixture or appliance case.

A table lamp will typically have a plug that is reversible. How do you consider dealing with that?

The way this is being dealt with here is by having a lamp socket that disconnects the base too as soon as you start unscrewing the the bulb, so that from the moment some part of the base becomes touchable it is not at risk of being live.

Again. Much safer not to make assumptions about wether live and neutral are correctly wired...

[rwidman]

Originally Posted by K_V_B

A table lamp will typically have a plug that is reversible. How do you consider dealing with that?.

It does not. One prong of the plug is wider than the other and the receptacle has one slot longer than the other. This is the neutral.

[rwidman]

Originally Posted by goboatingnow

..........

I know of no appliance that is compromised by reverse polarity. References to US ww2 appliances aside.

Dave

A table lamp as explained above.

[K_V_B]

Originally Posted by rwidman

It does not. One prong of the plug is wider than the other and the receptacle has one slot longer than the other. This is the neutral.

Not in this part of the world. In continental Europe the standard two prong plug is reversible. The most popular type of grounded plug (the German Schuko) is reversible as well.

This does not lead to dangerous situations.

[K_V_B]

Originally Posted by rwidman

A table lamp as explained above.

All table lamps in continental Europe come with reversible plugs... As explained above this does not lead to dangerous situations.