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Old 18-02-2015, 06:01   #181
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Re: Reverse Polarity

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Originally Posted by FlyingCloud1937 View Post
Would you like a minute to re-think.

I'll give you that anyways.

Now go back and re-read what I said.

Then as a good debater, thinking an argument from both sides, come back with a for and against.

I'll bet you find the answerer to my riddle, before I answer back.

Lloyd
Nope, not interested in playing games.

When you articulate the return path to the shorepower source, then we can discuss.
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Old 18-02-2015, 06:52   #182
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Re: Reverse Polarity

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Originally Posted by K_V_B View Post
Why not? There is no reason why you cannot earth the boat as well. That way you are not dependent on the shore power to be properly earthed.
There is a reason why you cannot "earth" the boat as well. It's a code violation. There is supposed to be a single ground and that is at the service entrance to the building (or facility).

When in doubt, it's best to check this yourself with a portable tester. I have been in situations where I was forced to use someone else's home made extension cord and found it dangerously miswired. I rewired it before I used it.

BTW: If you decide to ground the boat yourself (to a ground rod or metal pipe) and the power from the marina or whatever is miswired, you could find yourself in a shocking situation.

There are good reasons to follow the ABYC and NEC (where these apply). The folks who write these codes do so after much research and have access to information that the average boater does not have.
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Old 18-02-2015, 07:08   #183
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Re: Reverse Polarity

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Originally Posted by rwidman View Post
There is a reason why you cannot "earth" the boat as well. It's a code violation. There is supposed to be a single ground and that is at the service entrance to the building (or facility).
There is a single ground. It's called Earth, thus the frase "earth"
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Old 18-02-2015, 07:23   #184
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Re: Reverse Polarity

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Originally Posted by rwidman View Post
There is a reason why you cannot "earth" the boat as well. It's a code violation. There is supposed to be a single ground and that is at the service entrance to the building (or facility).

When in doubt, it's best to check this yourself with a portable tester. I have been in situations where I was forced to use someone else's home made extension cord and found it dangerously miswired. I rewired it before I used it.

BTW: If you decide to ground the boat yourself (to a ground rod or metal pipe) and the power from the marina or whatever is miswired, you could find yourself in a shocking situation.

There are good reasons to follow the ABYC and NEC (where these apply). The folks who write these codes do so after much research and have access to information that the average boater does not have.
Hmm, a boat wired to ABYC specs sitting in the water is (resistively) earthed!

A point of controversy about ABYC spec is the call to connect shorepower ground to boat DC ground. Since boat DC ground is connected to the water via engine/ground plates, the shorepower ground to DC ground creates earthing of the shorepower ground on the boat.

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Old 18-02-2015, 07:29   #185
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Re: Reverse Polarity

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Originally Posted by TeddyDiver View Post
There is a single ground. It's called Earth, thus the frase "earth"
A very common mis-conception. It's only a return path to the source when you connect 1/2 of said source to earth ground. If you don't make that connection, earth no longer can be a return path to that source.

Point: It's a man-made issue, not a natural phoenomon as some believe.
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Old 18-02-2015, 07:49   #186
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Re: Reverse Polarity

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Originally Posted by K_V_B View Post
That's why people in Europe never sleep. It goes POW all the time...

Seriously now. Do you think that an appliance maker that build stuff that became deadly when plugged in backward would not have been litigated in to oblivion ages ago?


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If ever you find yourself on the Outer Banks of NC looking for a rental unit avoid renting from Mr.Bare( aka Darth Vader) one of his tactics is to remove the ground prong from the refrig. and then reverse the polarity so that when you complain about being shocked by the door handle of the fridge he sends the "repairman" to fix it and charges you a crazy amount for said service..your right they dont make them that way **** just happens over time..
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Old 18-02-2015, 08:49   #187
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Re: Reverse Polarity

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Originally Posted by tropicalescape View Post
If ever you find yourself on the Outer Banks of NC looking for a rental unit avoid renting from Mr.Bare( aka Darth Vader) one of his tactics is to remove the ground prong from the refrig. and then reverse the polarity so that when you complain about being shocked by the door handle of the fridge he sends the "repairman" to fix it and charges you a crazy amount for said service..your right they dont make them that way **** just happens over time..
What you describe can only happen if before Mr Bare did those two things the fridge had an internal connection between neutral and its frame (as in damaged insulation that lets a wire touch the frame), which should not have been there. Go an test a new fridge and you will find no continuity between ground and neutral (or ground and hot).

The root cause is not reverse polarity. It is a connection between neutral and green that should not be there.
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Old 18-02-2015, 09:07   #188
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Re: Reverse Polarity

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Originally Posted by FlyingCloud1937 View Post
Not if the fault was at the line voltage prior to the RCD.

The RCD would not know of this fault.


Lloyd
It is unclear to me what you mean with "fault with line voltage". Do you mean to say the voltage problem was in the green wire? If so you can fix that using a separate rod for green (TT earthing) instead of tying green to neutral.

Of course, then you will have higher impedance between green and the neutral tap of the transformer and therefore will need an RCD to ensure hot-to-green faults will disconnect the circuit, but whole-boat RCDs are not only a good idea but also mandatory as per ABYC aren´t they?
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Old 18-02-2015, 09:24   #189
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Re: Reverse Polarity

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Originally Posted by rwidman View Post
There is a reason why you cannot "earth" the boat as well. It's a code violation. There is supposed to be a single ground and that is at the service entrance to the building (or facility).
Explain me how you can bind all metal parts to PE, and at the same time avoid creating extra paths to earth...
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Old 18-02-2015, 12:59   #190
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Re: Reverse Polarity

Everybody should google "Mike Holt" and read what he has to say. He is the grounding GURU.

Also take the little bit of time reading these articles, you will be better informed then reading most of the rubbish in the previous 188 post on this topic, to which I don't think the OP has even responded to.

Lloyd


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http://www.qualitymarineservices.net...%2012-2005.pdf

http://www.qualitymarineservices.net...%2010-2006.pdf

http://www.qualitymarineservices.net...Connection.pdf


11111111111111111111111111111111111111111111111111 11111111111111111111111111111111111111111111111111 11111111111111111111111111111111111111111111111111 1111111111
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Old 18-02-2015, 13:39   #191
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Re: Reverse Polarity

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Originally Posted by FlyingCloud1937 View Post
Everybody should google "Mike Holt" and read what he has to say. He is the grounding GURU.
Hey, I am sure we all have heard of Mike Holt Enterprises and his videos. Only guy in the world who mixes grounding with Bible quotes! I am sure he helps lots of people pass their code exams, but for some reason his "graduates" come out believing that people will get killed before a 30mA RCD will trip (false). This has effectively has been used as an excuse by misinformed people to slow the take-up on whole boat/house RCD use. Maybe we need to send to the US an old RCD salesman with the old trick of tripping with the hand just for fun

I would much rather see people read what Schafer (works with Holt) has written done on the issue of safety ground in US marinas..

Quote:
Originally Posted by FlyingCloud1937 View Post
Also take the little bit of time reading these articles, you will be better informed then reading most of the rubbish in the previous 188 post on this topic, to which I don't think the OP has even responded to.
Lloyd
Those articles have plenty of good stuff but they are almost two decades old. They miss the whole concept of whole-boat RCD that has been mandatory for new US boats for a few years now.
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Old 18-02-2015, 19:27   #192
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Re: Reverse Polarity

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Originally Posted by svlamorocha View Post
What you describe can only happen if before Mr Bare did those two things the fridge had an internal connection between neutral and its frame (as in damaged insulation that lets a wire touch the frame), which should not have been there. Go an test a new fridge and you will find no continuity between ground and neutral (or ground and hot).

The root cause is not reverse polarity. It is a connection between neutral and green that should not be there.
Ok ..The "repairman" that Mr.B sent out to "repair it" simply unplugged the refrigerator, turned the plug over and said that "people like you always fall for it" ok..billed me for more than a hundred dollars..Called it reverse polarity and I went with it with blind dedication..Now you know the depth of my electrical knowledge or should I say the lack of.. I hate the whole family of "the invisible biting beast" from the frail and weak 9 volt to the 110 "Volt Viper" in my house to the 220 "Electric Boa" on my planer/moulder..
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Old 19-02-2015, 00:36   #193
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Re: Reverse Polarity

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Originally Posted by DotDun View Post
A point of controversy about ABYC spec is the call to connect shorepower ground to boat DC ground. Since boat DC ground is connected to the water via engine/ground plates, the shorepower ground to DC ground creates earthing of the shorepower ground on the boat.
I don't find this that controversial. It's good practice in my opinion. It does create a problem with ground loops that can cause galvanic corrosion, but there are easy fixes for that.
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Old 19-02-2015, 01:16   #194
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Re: Reverse Polarity

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Originally Posted by svlamorocha View Post
Hey, I am sure we all have heard of Mike Holt Enterprises and his videos. Only guy in the world who mixes grounding with Bible quotes! I am sure he helps lots of people pass their code exams, but for some reason his "graduates" come out believing that people will get killed before a 30mA RCD will trip (false). This has effectively has been used as an excuse by misinformed people to slow the take-up on whole boat/house RCD use. Maybe we need to send to the US an old RCD salesman with the old trick of tripping with the hand just for fun
Yep a 30 mA RCD must hold at 22.3 mA's and below, unlimited time, this is in a fault situation. As well as hold for 100 mS for a 30mA fault.

So the RCD does not protect against the stray current corrosion fault,
and also subjects the most at risk humans to a lethal ground fault.

In the US we protect against the lowest denominator, which is children, and the elderly. Why? to save human life.

Lloyd
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Old 19-02-2015, 01:57   #195
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Re: Reverse Polarity

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Originally Posted by FlyingCloud1937 View Post
Yep a 30 mA RCD must hold at 22.3 mA's and below, unlimited time, this is in a fault situation. As well as hold for 100 mS for a 30mA fault.

So the RCD does not protect against the stray current corrosion fault,
and also subjects the most at risk humans to a lethal ground fault.

In the US we protect against the lowest denominator, which is children, and the elderly. Why? to save human life.
Can you quote a statistic of deaths to electrocution by earth fault where a 30mA did not trip?

Corrosion is another problem for which there are other solutions, and it it is not caused by AC anyway.


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