CPAPtalk.com

Cpapgreg wrote:

palerider wrote:

Cpapgreg wrote:I don't know if it is the same but when I was in the US Navy, there isn't a true ground so the neutral and hot lines both have 60V AC on them. If you had a power strip that grounds to the neutral line, you would get 60V AC on the metal case.
Very bad.

ah, no, that's NOT how it works.

In addition to other responses, ungrounded systems are also found on ships at sea. Since there is no reference to "earth ground", there is no true ground. A typical house or building wiring system will have a hot, neutral and ground: On board a ship you will have two hots, and a ground- but the "ground" is really the ship's hull. If you were checking voltage on a 120VAC circuit on a ship, you would find 55 volts between each hot and the "ground".

http://forum.allaboutcircuits.com/threa ... ystem.938/

the trick about reading things on the internet is separating the idiots from the people that have some knowledge, and checking your sources.

your quote above is *wrong*.

see http://www.brighthubengineering.com/mar ... d=noscript
and http://www.brighthubengineering.com/mar ... d=noscript

palerider wrote:

Cpapgreg wrote:

palerider wrote:

Cpapgreg wrote:I don't know if it is the same but when I was in the US Navy, there isn't a true ground so the neutral and hot lines both have 60V AC on them. If you had a power strip that grounds to the neutral line, you would get 60V AC on the metal case.
Very bad.

ah, no, that's NOT how it works.

In addition to other responses, ungrounded systems are also found on ships at sea. Since there is no reference to "earth ground", there is no true ground. A typical house or building wiring system will have a hot, neutral and ground: On board a ship you will have two hots, and a ground- but the "ground" is really the ship's hull. If you were checking voltage on a 120VAC circuit on a ship, you would find 55 volts between each hot and the "ground".

http://forum.allaboutcircuits.com/threa ... ystem.938/

the trick about reading things on the internet is separating the idiots from the people that have some knowledge, and checking your sources.

your quote above is *wrong*.

see http://www.brighthubengineering.com/mar ... d=noscript
and http://www.brighthubengineering.com/mar ... d=noscript

Your reading comprehension is what is lacking. Your links show a 3 phase distribution.
You know what, keyboard commando, you win. My 15 years on ship dealing with electrical systems mean nothing. I won't argue this anymore. Tell you what, next time you are on a ship, stick a fork into the neutral lead.

Cpapgreg wrote:Your reading comprehension is what is lacking. Your links show a 3 phase distribution.
You know what, keyboard commando, you win. My 15 years on ship dealing with electrical systems mean nothing. I won't argue this anymore. Tell you what, next time you are on a ship, stick a fork into the neutral lead.

since you've 'given up', I'll just explain to other people why your 'reasoning' is faulty.

as the engineering information linked above (not random blog comments) indicates, shipboard electrical systems are *isolated* neutral systems, therefore there is no normal connection to 'ground' (in this case, the metal of the ship, therefore, there will be no, zero, current flow between either the hot, OR neutral, to ship frame. to suggest otherwise is the same as saying that you'd get shocked touching one end of a battery while standing in a puddle of water.... there's simply no path for the current to flow.

that's the first nail in the coffin of that ~60 volts to 'ground', or '60 volts on both wires' allegation is that the120v circuit is *single phase* non-center tapped circuit. cpapgreg is making a false assumption based on the fact that, in the US, transformers take one leg of that three phase power, and put a 240v center tapped transformer on it, which gives you *two* hot wires, in relation to a neutral. none of that has anything to do with grounding, shipboard or in your house


you get 120v between either hot wire and the center neutral, you get 240v between the two hot wires. note that there is no '60v' in there anywhere... except in his imagination. also, please note that the + and - in the above diagram alternate 60 times a second in north america.

I hope the link below works because I am writing this on my semi - functional tablet. It is a document written by a USCG electrical engineer describing the dangers of using conventional surge protectors on ships. He describes in detail the electrical wiring of ships and that conventional surge protectors are very dangerous. In another Cruise only Board, the engineer that wrote the document explained in even deeper detail the issues. He also added that he had later been the Chief Electrical Officer for a cruise line and he ensured us that the same issues are present on any ship including cruise ships.

Ironically, I will be boarding a cruise ship tomorrow for an 11 day cruise. I wish that I had my voltmeter with me to settle this argument.

http://www.uscg.mil/tvncoe/Documents/sa ... evices.pdf

sptrout wrote:I hope the link below works because I am writing this on my semi - functional tablet. It is a document written by a USCG electrical engineer describing the dangers of using conventional surge protectors on ships. He describes in detail the electrical wiring of ships and that conventional surge protectors are very dangerous. In another Cruise only Board, the engineer that wrote the document explained in even deeper detail the issues. He also added that he had later been the Chief Electrical Officer for a cruise line and he ensured us that the same issues are present on any ship including cruise ships.

Ironically, I will be boarding a cruise ship tomorrow for an 11 day cruise. I wish that I had my voltmeter with me to settle this argument.

http://www.uscg.mil/tvncoe/Documents/sa ... evices.pdf

so what you're saying is we could both be right, depending on how the outlet is wired as well as the comment further upthread about cruise lines confiscating surge protectors.

sptrout wrote:I hope the link below works because I am writing this on my semi - functional tablet. It is a document written by a USCG electrical engineer describing the dangers of using conventional surge protectors on ships. He describes in detail the electrical wiring of ships and that conventional surge protectors are very dangerous. In another Cruise only Board, the engineer that wrote the document explained in even deeper detail the issues. He also added that he had later been the Chief Electrical Officer for a cruise line and he ensured us that the same issues are present on any ship including cruise ships.

Ironically, I will be boarding a cruise ship tomorrow for an 11 day cruise. I wish that I had my voltmeter with me to settle this argument.

http://www.uscg.mil/tvncoe/Documents/sa ... evices.pdf

Nah, he must be wrong too. Who trusts them pesky Electrical Engineer people.

Another possibility is that ships at sea might abide by the engineering criteria of their home port,
which may vary according to ship's registry. Are international "rules" sometimes considered voluntary?
I would definitely consider that.