Power Strips Confiscated

[Outerdog]

6 minutes ago, Globehoppers said:

I once watch a surge protector, attached to the cabin outlet and a computer, actually melt.  The ship's line surged with a voltage spike (this was 1985).  The computer survived without a problem. Good surge protectors work.  Plus, when used with devices that convert AC to DC for power, unlike a device like a coffee maker or hair dryer, they have no effect on ship's power.  

 

Surge protectors are not permitted. Simple as that. 

 

You do you cuz you're going to anyway, but let's hand out proper advice to others, mkay?

Edited July 29, 2019 by Outerdog

[Haboob]

3 hours ago, Globehoppers said:

I once watch a surge protector, attached to the cabin outlet and a computer, actually melt.  The ship's line surged with a voltage spike (this was 1985).

⋮

 

That's normal behavior for a surge protector plugged into ships' wiring after it's MOV component wears out.  That spike might have been a large one or just a tiny one that wore out the very last of the MOV.

 

Either way, if the unit was melting, it was hot enough to ignite a fire.  If you plan to keep using surge protectors, please don't book a cabin on a ship I'm on.

[chengkp75]

4 hours ago, Globehoppers said:

I once watch a surge protector, attached to the cabin outlet and a computer, actually melt.  The ship's line surged with a voltage spike (this was 1985).  The computer survived without a problem. Good surge protectors work.  Plus, when used with devices that convert AC to DC for power, unlike a device like a coffee maker or hair dryer, they have no effect on ship's power.  

I don't care what year it was, there is no way a ship's power would surge enough on a 110v circuit that a surge protector would be active.  There are absolutely no surge protection for any of the ship's electronics, never have been.  What you observed is the fatal flaw in using a surge protector on a ship, reverse voltage.  Due to the floating ground used on ships, the voltage in the ground wire can be higher than the voltage in either of the power lines, yet still below what a surge protector shunts at, and below what would harm your electronics, yet because it is seeing voltage in the opposite direction to what it was designed for, the MOV's fail in thermal runaway, at a low current as well, and starts to heat up and melt the device.

So, what you saw was a surge protector failing, not one doing it's job.

As for your statement that a surge protector has no effect when used with an AC/DC converter, that is simply rubbish, as the surge protector is on the AC side and doesn't care what happens to the power after the surge protector part.  Any consumer product that places a semiconductor between the power legs and ground will fail when a ground fault anywhere else on the ship happens.

Edited July 29, 2019 by chengkp75

[ALWAYS CRUZIN]

The hull of the ship is common ground. An excellent grounding source. 110vac  has two connections. One is ground with respect to the common ground, better know as the neutral. Which completes the circuit back to the power source.  The other has 110 vac with respect to either ground connection. The ground connection is the hole on a three pin socket. On a ship it goes to the power panel which is connected to the hull of the ship and the common connection at the source. At your home ground is a copper rod driven deep into the ground just outside of the wall where your power panel is located.  About 6 to 8 feet down. The hull of the ship performs the same function. So basically there is no difference between the 110 vac power on a ship vs the 110 vac power you have at home. Both have 60 hz and are very regulated to maintain the correct voltage and frequency. As stated. The melting of your so called surge protector was probably a defective surge protector. Power spikes on a ship would almost be extremely rare, almost impossible. However at home. Not so, including a lightning power spike. The ship is a far better ground than your ground rod you have at your home. It is only as good as the ground is wet. 

[chengkp75]

However, the major difference between shore wiring and ship's wiring, is that there is no "neutral".  Both the black and white wires, or the wide slot and narrow slot on an outlet are at 60 volt with reference to the ground wire.  This is what causes the problems with a surge protector, because a 220v or 440v ground anywhere else on the ship could send this voltage up the ground wire, which is higher than the line voltages, and so the surge protector sees a higher voltage in the opposite direction to that which it is designed to sense, and the semiconductors fail.

[ALWAYS CRUZIN]

39 minutes ago, chengkp75 said:

However, the major difference between shore wiring and ship's wiring, is that there is no "neutral".  Both the black and white wires, or the wide slot and narrow slot on an outlet are at 60 volt with reference to the ground wire.  This is what causes the problems with a surge protector, because a 220v or 440v ground anywhere else on the ship could send this voltage up the ground wire, which is higher than the line voltages, and so the surge protector sees a higher voltage in the opposite direction to that which it is designed to sense, and the semiconductors fail.

I certainly hope you know that many things that get plugged into a three prong outlet have the neutral and ground connected together. Chassis ground and neutral. What you are saying would blow up a lot of things. The narrow slot is hot (Black wire) The wide slot is Neutral white wire. The pin hole is ground. Green wire. Slot to slot is 120 vac. Wide slot to pin hole is ZERO voltage.

[ALWAYS CRUZIN]

Neutral-to-Safety-Ground Connection
In a residential or commercial electrical service, it’s common practice for the AC safety grounding conductor bus to be connected to the neutral bus. If you’ve ever looked into a main electrical panel ashore (not a subpanel as might be found in a garage or outbuilding), you will typically see white wires sharing a bus with uninsulated wires. The latter are AC safety grounding conductors; or you may see two separate buses that are connected. While this practice is fine on land, it most certainly does not work aboard a boat, and it’s where many do-it-yourselfers or otherwise experienced residential/commercial and some marine electricians make a potentially fatal flaw when installing or servicing marine electrical systems.In a properly wired system, current traveling aboard on the hot wire returns solely through the white wire, called the neutral. Because a boat floats in a conductive medium, interconnecting the green and white wires aboard affords current returning to its source—the transformer ashore in this case—through three paths: the white wire, the now-connected green wire, and the water via bonded underwater metal hardware such as the engine/propeller, strainers, and seacocks, sacrificial anodes. Contrary to popular belief, electricity takes all paths back to its source, not just the path of least resistance. This presents a clear hazard to swimmers, and those aboard may also be at risk, depending upon the nature of the fault Therefore, it is vitally important that the connection between the AC safety grounding wire and the neutral wire occur only at the power source. That means, at the onshore transformer supplying the dock shore cord, or at a generator or inverter—when and only when one of those is supplying power to the vessel. There are exceptions to this rule that involve the use of transformers; however, I’ll save those for another ATD column.If you have doubts about the neutral-to-ground connection(s) aboard any boat’s AC safety grounding system, check it with a multimeter. Zero voltage between neutral and ground.

The green AC safety-grounding conductor is often part of a larger onboard ground system that consists of the bonding system and the DC negative system. If ABYC guidelines are followed, these other “ground” systems are interconnected.

Remember, when connecting to shore power. Compatibly is a must.

 

 

[chengkp75]

5 minutes ago, twodaywonder said:

I certainly hope you know that many things that get plugged into a three prong outlet have the neutral and ground connected together. Chassis ground and neutral. What you are saying would blow up a lot of things. The narrow slot is hot (Black wire) The wide slot is Neutral white wire. The pin hole is ground. Green wire. Slot to slot is 120 vac. Wide slot to pin hole is ZERO voltage.

I am quite familiar with both shoreside wiring and shipboard wiring.  Shipboard wiring starts out with a 3-phase power transformer that steps down from 220v to 120v, and that transformer is "delta wound", so it has no neutral point that is grounded.  However, the generator is "wye wound" so there is a neutral point in the generator that is grounded.  Therefore, while the two hot leads (black and white) that come from the "corners" of the wye connection, are 120v apart, the voltage between either the black or white wires to ground is only 60v each.  While I am not an electronic expert, what you are describing is a "chassis" ground, which takes all of the "neutral" return legs in the circuitry and connects them at one point to the neutral.  This does not connect to the ground pin of the plug, that connects to the metal case of the device, so the "neutral" and ground are still separate, except back at your breaker panel.  And in a shore application, high voltage applied to the ground connection, will travel up the neutral as well, due to the connection in the breaker panel, and fry your electronics.

 

The neutral and ground on a ship are kept separate so that ground faults in equipment can be located.  If your device at home develops a ground fault on the "neutral" leg, nothing happens, but you also won't know that the insulation has failed.  On ship's we connect ammeters and resistors between the power legs and ground, but since there is no other connection between these power legs and ground, no current flows.  When something develops a ground fault, this completes the circuit, current flows, and the ammeter shows current flow, scaled as Megohms of ground resistance, and we can then isolate circuits to determine where the ground is.  Ground current flowing in a ship's hull leads to galvanic corrosion between dissimilar metals immersed in sea water, so ship's engineers are very conscious of ground faults.

 

Have plugged many electronics into shipboard wiring over 44 years, and never blew anything up that didn't have a ground fault in it.

 

See the USCG Safety Notice describing "delta" and "wye" connected circuits:

 

https://www.dco.uscg.mil/Portals/9/TVNCOE/Documents/SafetyAlerts/SurgeProtectiveDevices.pdf?ver=2017-08-11-142750-690

[chengkp75]

5 minutes ago, twodaywonder said:

Neutral-to-Safety-Ground Connection
In a residential or commercial electrical service, it’s common practice for the AC safety grounding conductor bus to be connected to the neutral bus. If you’ve ever looked into a main electrical panel ashore (not a subpanel as might be found in a garage or outbuilding), you will typically see white wires sharing a bus with uninsulated wires. The latter are AC safety grounding conductors; or you may see two separate buses that are connected. While this practice is fine on land, it most certainly does not work aboard a boat, and it’s where many do-it-yourselfers or otherwise experienced residential/commercial and some marine electricians make a potentially fatal flaw when installing or servicing marine electrical systems.In a properly wired system, current traveling aboard on the hot wire returns solely through the white wire, called the neutral. Because a boat floats in a conductive medium, interconnecting the green and white wires aboard affords current returning to its source—the transformer ashore in this case—through three paths: the white wire, the now-connected green wire, and the water via bonded underwater metal hardware such as the engine/propeller, strainers, and seacocks, sacrificial anodes. Contrary to popular belief, electricity takes all paths back to its source, not just the path of least resistance. This presents a clear hazard to swimmers, and those aboard may also be at risk, depending upon the nature of the fault Therefore, it is vitally important that the connection between the AC safety grounding wire and the neutral wire occur only at the power source. That means, at the onshore transformer supplying the dock shore cord, or at a generator or inverter—when and only when one of those is supplying power to the vessel. There are exceptions to this rule that involve the use of transformers; however, I’ll save those for another ATD column.If you have doubts about the neutral-to-ground connection(s) aboard any boat’s AC safety grounding system, check it with a multimeter. Zero voltage between neutral and ground.

The green AC safety-grounding conductor is often part of a larger onboard ground system that consists of the bonding system and the DC negative system. If ABYC guidelines are followed, these other “ground” systems are interconnected.

Remember, when connecting to shore power. Compatibly is a must.

 

 

And you are talking about a boat's wiring, not a ship's wiring.  Boats are "wye connected", ships are "delta connected", and as this notes, there is no connection between the ground and neutral, even on a boat, except at the shore side power connection, not on the boat.  And, most boats are DC, and typically fiberglass, not steel.

[ALWAYS CRUZIN]

16 hours ago, chengkp75 said:

And you are talking about a boat's wiring, not a ship's wiring.  Boats are "wye connected", ships are "delta connected", and as this notes, there is no connection between the ground and neutral, even on a boat, except at the shore side power connection, not on the boat.  And, most boats are DC, and typically fiberglass, not steel.

A fiberglass boat is wired totally different than a cruise ship or any metal ship for that matter. The article I posted are not my words. It is from a marine electricians article. Think about this for a second. Let's say a screw goes through the hot wire and then into the bulk head. Now the ship is hot. So s the water surrounding the ship. That is if the ground and the neutral are not connected together. If they are it would pop the breaker. I am done here. I must always be incorrect because you are always correct on everything and every topic. Awesome.

[ALWAYS CRUZIN]

herefore, while the two hot leads (black and white) that come from the "corners" of the wye connection, are 120v apart, the voltage between either the black or white wires to ground is only 60v each. Better not be in a state room.  Again a 120vac outlet on a ship does NOT have 60 vac from neutral to ground. Totally incorrect. A 220 vac would be 110 vac to ground on either leg that is because both are HOT with 110 vac only one connection is hot. Any voltage at all and current at all between neutral and ground is extremely dangerous. 

[ALWAYS CRUZIN]

Back to the topic. Taken and posted here.

Why can’t I use a power strip from home?

In short, fire is the greatest danger at sea, and these devices may not prevent faults like they’re supposed to. I’ll try and keep this simple so we don’t go off an electronics-engineering deep end (only to be corrected by actual electronic engineers). Your home power strips will certainly work on a cruise ship, but they aren’t safe for a rather ironic reason. The circuit breaker that is supposed to protect you from fire due to short-circuits or overload may not work right on a ship. These breakers generally rely on disconnecting the ‘hot’ wire in your AC circuit, leaving only the neutral and ground wires connected. Because a ship generates electricity in a different way, and has a somewhat different method of grounding, there is a chance that the circuit could become overloaded, but tripping the power strip’s built in breaker will not stop the flow of electricity. If you want to better understand this, I’d check out this article from the US Coast Guard.

[ALWAYS CRUZIN]

7 minutes ago, twodaywonder said:

Back to the topic. Taken and posted here.

Why can’t I use a power strip from home?

In short, fire is the greatest danger at sea, and these devices may not prevent faults like they’re supposed to. I’ll try and keep this simple so we don’t go off an electronics-engineering deep end (only to be corrected by actual electronic engineers). Your home power strips will certainly work on a cruise ship, but they aren’t safe for a rather ironic reason. The circuit breaker that is supposed to protect you from fire due to short-circuits or overload may not work right on a ship. These breakers generally rely on disconnecting the ‘hot’ wire in your AC circuit, leaving only the neutral and ground wires connected. Because a ship generates electricity in a different way, and has a somewhat different method of grounding, there is a chance that the circuit could become overloaded, but tripping the power strip’s built in breaker will not stop the flow of electricity. If you want to better understand this, I’d check out this article from the US Coast Guard.

More excellent reading and a complete explanation of the power strips and grounding.

Cruise lines are pretty picky regarding guests thwarting cabin electrical systems and pertinent ship policy. In my opinion, justifiably so. #1 reason is due the greatest fear on board vessels--- "FIRE". They have other excellent reasons as well. I.e.:

Courtesy: O5MakO5

"Most surge protectors are in the form of power strips, which allow multiple devices to be attached to the same surge protector. Unfortunately this also allows people to attach more devices to a single wall socket than is safe. Attempting to draw more power from the wall than the hardware can handle can cause fires. Please leave your surge protectors, power strips & extension cords at home. Cheap ones are extremely dangerous as are the older models (I'm told by an electrician that we should replace ours every 2 years.) Engineers have very carefully calculated the amount of electricity to run the ship and how many outlets can safely be installed in each stateroom. I do agree that all of the cruise line should do a better job of informing their passengers to the danger of overload. People seem confused and unaware of why the number of outlets are minimum. Trace Atkins' home is a total loss due to a faulty power strip"

Courtesy: Capt. B.J.:

"The electrical systems you find on land are not exactly what you find in the shipboard environment. The difference has to do with grounding. On land we ground to that .... the ground! Or EARTH. And we do that thru wires - we hope, but a little loose current in the foundation is no biggie
On a ship you ground to the sea if you followed the same principle, problem is the ship is steel and if the ship's hull transmits any of that juice to the sea a bad thing happens - actually several. For one - electrolysis - the flow of electrons away from the ship carries molecules of metal. The hull erodes to the point that ships develop weakened hulls and even holes in the props and rudders. Not good things. (ships try to mitigate this which can never be totally eliminated by attaching a sacrificial metal to the hull. One that will carry away more easily then the metal of the hull. These blocks of ZINC are seen even on smaller boats and outboard motors. Zincs are one of those items that are checked and replaced as needed during a dry dock period.) Also if there is a 'short' or a 'ground' on a ship that can cause the walls and floors and everything else to be electically hot - ships are not framed in wood anymore. It is very very important to keep the electric distribution on a ship a closed system. It is different than on land.
So what? Well, most power strips are also surge protectors and the way surge protectors work on land is most of the time not completely friendly to a ship's grounding system. How unfriendly? I have honestly seen a surge protector power strip burst into flames with no warning what so ever. I was involved with some of the first installations of desktop computers on ships for the organization that paid me. We learned this the hard way and eventually there were Navy safety warnings about the dangers of powerstips/surge protectors/and interruptible power supplies on ship's. There were only a limited few models that were approved for shipboard use - UL TESTING HAS LIMITED APPLICATION IN THE SHIP ENVIRONMENT"

Courtesy: Hypo:

"I believe that the reasons for the cruise companies trying to limit the use of these devices on their ships is that they have no control over the quality of the device nor of the physical condition of the devices that people bring on board." For what its worth - extension cords were also strongly frowned upon because of the increased dangers associated with a frayed cord in the marine environment. Cords which were approved for use were regularly inspected and tagged as such ..."

[satxdiver]

To muddy the water a bit remember that we are talking about AC (alternating current) and not DC (direct current).   In an AC circuit the ground wire/white wire does not carry any electron flow but merely a reference point.  The electron flow is in the black/red wire where one half of the cycle the electrons flow one way and the other half of the cycle they flow the other way at a rate of 60 cycles/second or hertz.  The electrical device has to have a reference to ground which in most cases is the white wire.  Some electronic devices are designed to have a floating ground which is insulated from what we call ground.  In many cases the floating ground can and will have a potential difference from earth ground.

 

 

 

 

 

 

[chengkp75]

1 hour ago, twodaywonder said:

Think about this for a second. Let's say a screw goes through the hot wire and then into the bulk head. Now the ship is hot. So s the water surrounding the ship.

 

37 minutes ago, twodaywonder said:

If you want to better understand this, I’d check out this article from the US Coast Guard.

Sigh, so not only did you not read the USCG Safety Notice that I linked, but you didn't read the exact same safety notice you linked to above.  It describes how a shipboard 120v system can have a "floating ground" where there is 60v between the "neutral" and the ground.  I understand that you have an animus against believing anything I say, but I guess you know better than the maritime experts at the USCG Cruise Ship Center of Excellence, which authored that Safety Notice, and which is comprised of professionals and experts from many branches of the maritime industry; regulatory, classification societies, ship owners, and ship builders, who have collective centuries of experience in the maritime world.  Maybe reading this will convince you.

 

Your first statement above, shows a complete lack of understanding of basic electricity and grounding.  Even in your first post, you stated that the hull and the sea water are very good conductors to ground (meaning virtually zero resistance), and when you have zero resistance between two points, you have zero potential difference (voltage), and without voltage, you can't have current flow.  So, if I drive a screw into a hot wire, and then into the bulkhead (hull), that hot wire is now dead shorted to ground (zero resistance).  Since there is a voltage difference, there will be an instantaneous virtually infinite current (voltage divided by resistance (zero), and this infinite current will trip the circuit breaker, and no current will flow.

 

Now, lets look at the post where you quote a post asking about using a power strip from home.  As I noted to that person when they posted it, while it is true that the power strip only interrupts the hot leg, the ship's circuit breaker, even for 120v circuits, unlike in your house, is a two pole breaker, and interrupts both legs of the power, for just this reason.

 

As to 05Mak05:  Excess current has absolutely nothing to do with a surge protector, again showing a lack of understanding of electricity.  Surge protection shunts excessive voltage to ground.  Merely having a power strip, even without a surge protector, can cause a fire hazard on a ship, just like it can at your house, if you plug too much into it.  However, both your house, and the ship have circuit breakers further upstream that will trip in over current situations.

 

Now, you do understand that current will take any path to flow, not just the one with the least resistance.  So, if you connected the neutral to the ground, some of the current coming  from the hot to the "neutral" might take the path through the ground, and you get the exact situation that CaptB_J mentions of galvanic corrosion due to current flowing between dissimilar metals in the hull (each metal has its own base potential, so you get a battery effect), so that is why he says they don't connect the neutral to the ground.

 

Several decades ago, when we first started installing UPS systems for desktop computers on ships, we found that none of the "consumer" "land based" UPS's that you would use at home or at the office would work.  They immediately went to battery, showing "voltage failure" and would not reset.  Why?  Because they were looking for 120v hot to ground as "normal" mains voltage, and ships don't provide this.

[chengkp75]

49 minutes ago, satxdiver said:

 In an AC circuit the ground wire/white wire does not carry any electron flow but merely a reference point.

Well, the ground wire might not carry any current, but the white wire (neutral) sure does.  And where the neutral and ground are connected, the ground wire might carry current, as current will take any path to ground, not just the path of least resistance.  The current in the ground may be minute, but it can still be there.

[chengkp75]

2 hours ago, twodaywonder said:

herefore, while the two hot leads (black and white) that come from the "corners" of the wye connection, are 120v apart, the voltage between either the black or white wires to ground is only 60v each. Better not be in a state room.  Again a 120vac outlet on a ship does NOT have 60 vac from neutral to ground. Totally incorrect. A 220 vac would be 110 vac to ground on either leg that is because both are HOT with 110 vac only one connection is hot. Any voltage at all and current at all between neutral and ground is extremely dangerous. 

Okay, while you are talking about a land based wiring system, I agree that a 220v circuit has 110v to ground, and there is no "neutral".  Now, if I take my "dual voltage" hair dryer (rated at 100-240vac), and plug it into this 220v circuit, are all kinds of bad things going to happen because the "neutral" is at a different voltage than the ground?  Of course not, and a ship's 120v circuit is wired just like the home 220v circuit, and I can plug this same dual voltage hair dryer into a ship's 120v outlet, and nothing bad happens, even though the "neutral" is not at the ground voltage.

 

 

[Thrak]

It's really simple. Surge protected power strips are not allowed on the ship. I don't understand why people can't just follow the rules. It's not at all hard to comply.

[MissP22]

35 minutes ago, Thrak said:

It's really simple. Surge protected power strips are not allowed on the ship. I don't understand why people can't just follow the rules. It's not at all hard to comply.

No it's not but Princess doesn't really make a point of letting people know what is & isn't allowed. 

It's mentioned but you have to go out of the way to find it & how many people actually do?

[Outerdog]

13 minutes ago, MissP22 said:

No it's not but Princess doesn't really make a point of letting people know what is & isn't allowed. 

It's mentioned but you have to go out of the way to find it & how many people actually do?

 

Many people try to come here and find the correct information, only to be met with "experts" who use prohibited equipment, but "have never had a problem". These people are dangerous. They think they know everything and are very annoying to people that do. Equally as bad are those who search the internet and copy/paste technical information with no associated experience, or worse, they don't even read what they post!

 

I've never seen chengkp75 admit that he's wrong. The likely reason for this is that he never is.

 

 

[MissP22]

2 minutes ago, Outerdog said:

 

Many people try to come here and find the correct information, only to be met with "experts" who use prohibited equipment, but "have never had a problem". These people are dangerous. They think they know everything and are very annoying to people that do. Equally as bad are those who search the internet and copy/paste technical information with no associated experience, or worse, they don't even read what they post!

 

I've never seen chengkp75 admit that he's wrong. The likely reason for this is that he never is.

 

 

I'd venture to say that out of 1,500 cabins maybe 10% might actually realize that surge protected devices are not allowed and most people do bring power strips since there are so few outlets to charge anything.

 

Many of the ones that are brought aboard aren't collected during check in.

 

Luckily there haven't been more accidents. 

[toads45froggy]

Green is ground. as my electrician friend always has to remind me.

[triple7tahoe]

On 7/25/2019 at 9:06 AM, MissP22 said:

Was it at least returned on the last day?

We were asked to come to the naughty room on our cruise on the Majestic Princess earlier this year; I figured they were going to take our tea pot (which we have taken on over 100 cruises with no problem) only to find they were taking our power strip. It was returned as we left the ship on the last day (of that cruise). Since we were sailing B2B cruises, it was taken again as we reboarded 🙂  Finally got it back some three weeks later when we got off in Hong Kong.

[antsp]

So to cut a very long and sometimes very boring thread short.  DO NOT bring a surge protected extension plug. Bring a regular one. ( that may still be confiscated )

Edited July 31, 2019 by antsp

[Colgate59]

The issue is with Surge Protected power boards, not plain power boards.  If there is a surge or short in the item plugged into the board it can catch fire.  The board will not isolate the power.  It is not just an issue for the distribution board on the ship.  It can compromise the ships safety and yours and mine.  So please don’t bring one on.