Power Strip

[xlxo]

In addition to voltage... there's also hz. Are all cruise ships at 60hz like US/Canada outlets? I know some devices do not like 50hz when I take them to Asia.

[thepie]

I'm glad to have read the comments on this post. As far as I'm concerned I will watch what we plug in so we will not put any lives in jeopardy or damage the ship in any way..

[ccrain]

The surge suppressor installed in most power strips are the Metal Oxide Varistor kind. Its known as a "clamping" device as opposed to a "crowbar" device. A clamping device will take to ground that portion of the voltage surge that is over its breakdown voltage. So if you have a 200 volt MOV, and it sees a 240V surge, it will take that extra 40V to ground in the first order approximation. If that 40V is constant, the MOV will fail, typically short to ground, then explode or burn open. That is probably what happened on AE_Collector's strip (been to a good tequila tasting lately?).

 

Cheap 5 to 10 mm disc size MOV can't handle very many surges before they go south as well. And when surge protector strips say they handle so many joules, they typically achieve it by paralleling small MOVs, which is total BS, as the first small MOV that fails causes the issues.

 

Now the important thing to realize is the voltage in your 110/120VAC line is NOT 110 to 120Volts! That's the RMS (Root Mean Squared) voltage. Its actually around 170V zero to peak and 340V peak to peak. That's why most really good power strips use higher voltage MOVs and larger disc size MOVs.

 

Voltages on a ship can vary greatly. Ever see the lights dim or go bright? That's a voltage sag or surge and it happens all the time. Cheap surge protectors might not be able to handle even a single over voltage surge on a 120VAC line. So unless you take the time to really look at the UL ratings of surge protectors, it is better off to have one with no surge protection rather than the wrong surge protection, as in this case the surge protection actually caused the issue.

 

Most of todays electronics, like the brick on your laptop, are far better at handling surges than in the past. Even the multi-port USB charges can handle most of the surges you can get from a ship's power system, and the battery chargers are also pretty robust. The main reason to have a surge protector at home is that the power line surges and lightning at home are far more powerful and deadly, especially direct strike lightning, to home electronics.

 

OK, sorry to go a little off topic, I've managed to hit the reset button now..

[Colo Cruiser]

The surge suppressor installed in most power strips are the Metal Oxide Varistor kind. Its known as a "clamping" device as opposed to a "crowbar" device. A clamping device will take to ground that portion of the voltage surge that is over its breakdown voltage. So if you have a 200 volt MOV, and it sees a 240V surge, it will take that extra 40V to ground in the first order approximation. If that 40V is constant, the MOV will fail, typically short to ground, then explode or burn open. That is probably what happened on AE_Collector's strip (been to a good tequila tasting lately?).

 

Cheap 5 to 10 mm disc size MOV can't handle very many surges before they go south as well. And when surge protector strips say they handle so many joules, they typically achieve it by paralleling small MOVs, which is total BS, as the first small MOV that fails causes the issues.

 

Now the important thing to realize is the voltage in your 110/120VAC line is NOT 110 to 120Volts! That's the RMS (Root Mean Squared) voltage. Its actually around 170V zero to peak and 340V peak to peak. That's why most really good power strips use higher voltage MOVs and larger disc size MOVs.

 

Voltages on a ship can vary greatly. Ever see the lights dim or go bright? That's a voltage sag or surge and it happens all the time. Cheap surge protectors might not be able to handle even a single over voltage surge on a 120VAC line. So unless you take the time to really look at the UL ratings of surge protectors, it is better off to have one with no surge protection rather than the wrong surge protection, as in this case the surge protection actually caused the issue.

 

Most of todays electronics, like the brick on your laptop, are far better at handling surges than in the past. Even the multi-port USB charges can handle most of the surges you can get from a ship's power system, and the battery chargers are also pretty robust. The main reason to have a surge protector at home is that the power line surges and lightning at home are far more powerful and deadly, especially direct strike lightning, to home electronics.

 

OK, sorry to go a little off topic, I've managed to hit the reset button now..

 

Excellent explanation.

 

Long story short, the electrician won't laugh. :cool:

[Meanee]

 

 

See! No need to search out an electrician for quality advice. If it puts out 120 volts AC it must be "no different from your apartment". Not what the attached link to the warning about using surge protectors at sea said about ships power at all.

 

Terry

 

 

Yeah, everyone's an expert.

 

How many accidents were there on cruise ships due to surge protectors? I am sure zero lives were lost due to one.

[sptrout]

Below is a link to a good description of the AC power systems of ships (written by an electrical engineer in the Coast Guard). Has described, AC power at home is NOT the same as on ships; cruise ships or others.

 

[AE_Collector]

Thanks for the additional info Charles (ccrain). I suggest we meet on shore at Cozumel and head down the road a bit to discuss this in further detail. We haven't been to a better Tequila tasting since but we did get back on Ruby Princess for 7 weeks on January 31 to go all the way around South America.

 

I have a couple more of the identical small surge protector power bars here (1 foot cord and just 4 outlets - very compact), bought at the same time and still in the packaging. My plan after "the incident" was always to open one up and remove the MOV's for cruises but having a wife has dictated that no power bars get to vacation with us now since the "Constellation Incident".

 

Celebrity now "owns" my melted power bar as while they were not mad or upset with us at all they did ask if they could take the evidence wth them as they vacated our cabin. So I didn't have an opportunity to do an autopsy but since the melting was centered around where the cord enters and the switch is located it seemed that the MOV's which would also be right there had to be the problem.

 

I did hear a rumour while onboard that we may not have been the only ones who had power bar issues that day which also leads me to believe that there was some sort of incident on some of the ships circuit(s) that caused the MOV's to go to ground and overheat.

 

Terry

Edited July 19, 2015 by AE_Collector

[sptrout]

Yeah, everyone's an expert.

 

How many accidents were there on cruise ships due to surge protectors? I am sure zero lives were lost due to one.

 

Using that logic then I guess it is OK to allow irons? Did you know that there has never been a fire caused by an iron in a passenger cabin? You would be hard pressed to find an iron caused fire anywhere in the last 50-100 years.

 

Extension cords are more of a tripping hazard than a fire issue. With today's low power consuming devices (cell phone chargers, computer and accessories, for example), it is almost impossible to overload an extension cord.

 

I guess smoking is OK too? Other than Princess almost losing a ship several years ago, no one has died. Hasn't been any deaths that I know of.

 

Having surge protectors on a ship is not only dangerous as had been well described, in fact, they are pretty much useless anyway. MOV based surge protectors are one baby step above nothing and are no longer used in many commercial applications because they gradually become worthless with no way to know it. As a retired Radio System Engineer, it was our company's policy to forbid the use of MOV surge protectors in our multi-million dollar systems except as backup for the primary devices (Silicon Avalanche Diode protectors).

[emmak8]

Visit Amazon and read the reviews. The newer electronics don't take long to charge.

[scott4020]

That's it, I'm gonna take my Fluke on my next cruise and definitively prove how these outlets are wired :)

 

BTW it's gonna be two hot lines, anyone want to bet?

[AE_Collector]

I already thought that i want to take my Fluke next time to see if it is Wired Delta but it sounds as though it must be. Now I am going to open up one of my identical power bars to the one that melted to see if it has 1 or 2 MOV's in it.

 

Terry

Edited July 19, 2015 by AE_Collector

[custompcsys]

Swiss Army stuff isn't necessarily cheap. Unfortunately their website states this is "...not available at this time".

 

Amazon doesn't have it either but it looks like its available on ebags

 

http://www.ebags.com/product/victorinox/travel-power-strip/285978?productid=10341118&lastsearchterm=travel+power+strip

[Treven]

Amazon doesn't have it either but it looks like its available on ebags

 

http://www.ebags.com/product/victorinox/travel-power-strip/285978?productid=10341118&lastsearchterm=travel+power+strip

I just bought one. Looking forward to checking it out, "up close and personal". It looks like it will be an ongoing fixture in my travel bag.

[trbarton]

Here's what I've been using bought from Amazon. I'm enclosing a photo to make it easier to see.

 

I paid $15.62 including shipping and taxes and it is great because besides the 3 plugs there is also 2 USB ports. You can also swivel the plug to fit in any direction. I always remember to remove it and store it in a drawer when I'm not using it.

 

Tom😎

[Treven]

Tom, I bought a Belkin a few years ago and just didn't care for it. It certainly does the job, but I just didn't like all my power cords jumbled up at the electrical outlet. I don't recall if I threw it away, or if I simply stuck it in a bag and forgot where I put it. I guess I wasn't interested enough to look for it.

Edited July 19, 2015 by Treven

[smellycruzer]

Traveling on the Ocean Princess in August with two iPads, two iPhones and a camera that will all need charging every day. Can someone recommend a power strip that is small enoigh to pack but will handle thes five devices? Many thanks

 

Pete

 

I'd recommend this one - http://www.amazon.com/dp/B00UKY4N6S

[Steelers36]

Our surge protector/power strip set off an alarm in the bridge and was collected until the end of the cruise when we were on the Diamond transpacific years ago. We had successfully used it on ships prior to that, but haven't used it since. Now we use a short extension cord.

 

Agree .. we use a simple compact extension bar with multi-plugs from IKEA. No surge protection.

[peety3]

Since when is a cruise ship not a commercial ship? Read the document. Read the part about two-thirds down about maritime electrical systems and how they are different from most land-based systems. Cruise ships are wired just like other large vessels for good reasons.

I read the whole document. I've read it several times - everybody comes back to this same document, and fails to read it.

 

Residential power (120V) uses three wires: a "hot" wire (120VAC relative to ground), a "neutral" wire (0VAC relative to ground), and a "ground" wire. The neutrals are used to return the no-longer-motivated electrons back to the generator to get re-motivated. The grounds are used to provide a safety connection so if wires come loose, etc., the 120VAC has an alternate safety path back to the generation system.

 

Residential electric ovens, water heaters, and dryers (240V) use four wires: a "hot1" wire (120VAC relative to ground), a "hot2" wire (120VAC relative to ground, but exactly 180 degrees out of phase with hot1, thereby creating 240V potential across the two hots), a "neutral" (0VAC relative to ground), and a ground wire. 240VAC allows the appliance to consume the same power as an imaginary 120VAC twin, but with half the current per hot leg.

 

Commercial ships have very little electrical consumption relative to the overall power demand, and the electrical consumption is scattered throughout the ship (radar head here, bridge there, cabins over here, etc.). To keep the current draw down, and therefore the wire size smaller and less expensive, they provide 120VAC to the cabins with a 60VAC hot1, a 60VAC hot2, and a ground wire (since the neutral is effectively useless). It's this 60V/60V power (net 120V) that causes fires on commercial ships, as the power strip circuit breaker doesn't open the hot2 leg when there's a problem, only the hot1. (It's also used for musicians, as the "balanced/symmetrical power" makes guitar amps SILENT instead of the incessantly hissing beasts that they normally are: http://www.furmansound.com/product.php?div=01&id=P-2400IT)

 

Cruise ships have so much power draw throughout the areas of the ship, with lots of distribution points throughout. If they tried to do 60V/60V balanced power, they'd have to install double-pole circuit breakers on EVERY circuit, and run twice the (effective) wire size out to every panel. That'd not only cost too much, but weigh too much. Cruise ships do 120VAC on hot1, 0VAC on neutral, and ground just like home. I've metered it...thanks for asking.

[Mommypig]

I have a charger that has 5 USB ports on it, and a single plug. Made by Anker, purchased through Amazon. And we have an extension cord with one plug and three sockets.

[chengkp75]

The surge suppressor installed in most power strips are the Metal Oxide Varistor kind. Its known as a "clamping" device as opposed to a "crowbar" device. A clamping device will take to ground that portion of the voltage surge that is over its breakdown voltage. So if you have a 200 volt MOV, and it sees a 240V surge, it will take that extra 40V to ground in the first order approximation. If that 40V is constant, the MOV will fail, typically short to ground, then explode or burn open. That is probably what happened on AE_Collector's strip (been to a good tequila tasting lately?).

 

Cheap 5 to 10 mm disc size MOV can't handle very many surges before they go south as well. And when surge protector strips say they handle so many joules, they typically achieve it by paralleling small MOVs, which is total BS, as the first small MOV that fails causes the issues.

 

Now the important thing to realize is the voltage in your 110/120VAC line is NOT 110 to 120Volts! That's the RMS (Root Mean Squared) voltage. Its actually around 170V zero to peak and 340V peak to peak. That's why most really good power strips use higher voltage MOVs and larger disc size MOVs.

 

Voltages on a ship can vary greatly. Ever see the lights dim or go bright? That's a voltage sag or surge and it happens all the time. Cheap surge protectors might not be able to handle even a single over voltage surge on a 120VAC line. So unless you take the time to really look at the UL ratings of surge protectors, it is better off to have one with no surge protection rather than the wrong surge protection, as in this case the surge protection actually caused the issue.

 

Most of todays electronics, like the brick on your laptop, are far better at handling surges than in the past. Even the multi-port USB charges can handle most of the surges you can get from a ship's power system, and the battery chargers are also pretty robust. The main reason to have a surge protector at home is that the power line surges and lightning at home are far more powerful and deadly, especially direct strike lightning, to home electronics.

 

OK, sorry to go a little off topic, I've managed to hit the reset button now..

 

I'm the one quoted "in the other threads" that beats this to death, and posts the USCG Safety Notice. I have been a merchant ships engineer for 40 years, including 4 years on cruise ships, and I can tell you that no marine electrician will tell you there is any appreciable difference between cargo ships and passenger ships.

 

While nearly all of your points are spot on, and I thank you for your assistance in my crusade to educate the cruising public, I will pick fault with one point.

 

Generally, the changes in light intensity you see on a ship are caused by a combination of frequency and voltage fluctuations. These are caused because the mechanical diesel engine cannot react as fast to load changes as the electrical load varies. This results in speed variations of the engine, which directly affects the frequency of the power, as the only thing that can return frequency to normal is the engine returning to reference speed. While speed changes will affect voltage, the solid state voltage regulators will react quicker than the engine, and will limit the voltage swings. So, more of the dimming of lights is from frequency than voltage swings.

[chengkp75]

I read the whole document. I've read it several times - everybody comes back to this same document, and fails to read it.

 

Residential power (120V) uses three wires: a "hot" wire (120VAC relative to ground), a "neutral" wire (0VAC relative to ground), and a "ground" wire. The neutrals are used to return the no-longer-motivated electrons back to the generator to get re-motivated. The grounds are used to provide a safety connection so if wires come loose, etc., the 120VAC has an alternate safety path back to the generation system.

 

Residential electric ovens, water heaters, and dryers (240V) use four wires: a "hot1" wire (120VAC relative to ground), a "hot2" wire (120VAC relative to ground, but exactly 180 degrees out of phase with hot1, thereby creating 240V potential across the two hots), a "neutral" (0VAC relative to ground), and a ground wire. 240VAC allows the appliance to consume the same power as an imaginary 120VAC twin, but with half the current per hot leg.

 

Commercial ships have very little electrical consumption relative to the overall power demand, and the electrical consumption is scattered throughout the ship (radar head here, bridge there, cabins over here, etc.). To keep the current draw down, and therefore the wire size smaller and less expensive, they provide 120VAC to the cabins with a 60VAC hot1, a 60VAC hot2, and a ground wire (since the neutral is effectively useless). It's this 60V/60V power (net 120V) that causes fires on commercial ships, as the power strip circuit breaker doesn't open the hot2 leg when there's a problem, only the hot1. (It's also used for musicians, as the "balanced/symmetrical power" makes guitar amps SILENT instead of the incessantly hissing beasts that they normally are: http://www.furmansound.com/product.php?div=01&id=P-2400IT)

 

Cruise ships have so much power draw throughout the areas of the ship, with lots of distribution points throughout. If they tried to do 60V/60V balanced power, they'd have to install double-pole circuit breakers on EVERY circuit, and run twice the (effective) wire size out to every panel. That'd not only cost too much, but weigh too much. Cruise ships do 120VAC on hot1, 0VAC on neutral, and ground just like home. I've metered it...thanks for asking.

 

I'm not following your argument about running twice the "effective" wire size out to every panel. Why? Wire size is determined by current, not voltage. And the reason that ground and neutral on a ship are not at the same voltage, like at home, is that your home is not made of steel, or immersed in salt water. Stray currents, or designed currents if the neutral and ground are common, in a steel hull in sea water will produce galvanic action, resulting in corrosion of the hull or other different metals in the ship. For this reason, a resistor is placed between the hot legs (both of them), and the ground, and an ammeter is placed in series. This ammeter is used to determine if something has accidentally gone to ground, so if your neutral and ground are common (as they are in your home, connected at the breaker panel), this would always show dead ground.

 

If surge protectors are not dangerous, or were required, why does Carnival specifically call out surge protectors as being not allowed?

 

And if surge protectors are needed, why is it that nothing on the ship, from the PC's that control the engine room automation and the bridge navigation equipment, to the PLC's that handle most functions onboard, including the slot machines in the casino, is protected by a surge protector?

Edited July 20, 2015 by chengkp75

[Colo Cruiser]

Boom!

[peety3]

I'm not following your argument about running twice the "effective" wire size out to every panel. Why? Wire size is determined by current, not voltage. And the reason that ground and neutral on a ship are not at the same voltage, like at home, is that your home is not made of steel, or immersed in salt water. Stray currents, or designed currents if the neutral and ground are common, in a steel hull in sea water will produce galvanic action, resulting in corrosion of the hull or other different metals in the ship. For this reason, a resistor is placed between the hot legs (both of them), and the ground, and an ammeter is placed in series. This ammeter is used to determine if something has accidentally gone to ground, so if your neutral and ground are common (as they are in your home, connected at the breaker panel), this would always show dead ground.

If 10 cabins need 10 120V/15A circuits, they could feed a panel with 240V@75A (aka two 120V@75A incoming feeds), install 10 breakers @ 15A each, and run 12/3 cable to each cabin. Or they could feed a panel with 120V@150A (aka two 60V@150A incoming feeds), install 20 breakers (10 double-pole breakers)@15A each, and run 12/3 cable to each cabin. Running 150A feeder cables to every panel requires bigger wire than running 75A feeder cables to every panel.

 

IF (and I mean IF) they really did balanced 60V/60V power on cruise ships, there's no longer a neutral, so your comment about stray voltage is way off, 60V off.

 

Who's saying that surge protectors are needed?

[chengkp75]

If 10 cabins need 10 120V/15A circuits, they could feed a panel with 240V@75A (aka two 120V@75A incoming feeds), install 10 breakers @ 15A each, and run 12/3 cable to each cabin. Or they could feed a panel with 120V@150A (aka two 60V@150A incoming feeds), install 20 breakers (10 double-pole breakers)@15A each, and run 12/3 cable to each cabin. Running 150A feeder cables to every panel requires bigger wire than running 75A feeder cables to every panel.

 

IF (and I mean IF) they really did balanced 60V/60V power on cruise ships, there's no longer a neutral, so your comment about stray voltage is way off, 60V off.

 

Who's saying that surge protectors are needed?

 

Okay, so what you are saying is that they are running the same breaker panels as you have at home, where there are two hot legs at 240v, and a neutral? That isn't what is done.

 

Actually, there is a neutral, but it is not on the 120v or 240v circuits, it is on the 10k volt generator, which is Wye wound. The ground wire in the receptacle is sent all the way back to the generator neutral point to provide the anti-shock protection of a ground, without sending current through the hull. As I say, since there is a 60v difference between both of the hot legs, it is easy to measure any current flowing to ground, with the resistor and ammeter as I mentioned. Electrical equipment at sea frequently develops grounds, so measuring these grounds is very important. If there was no voltage between the neutral and ground, anything could go to ground through the neutral leg, and you would never know it. In your home, the only way you know about a ground of the neutral leg is to use a ground fault circuit breaker, which measures the difference in current between the two legs.

[Treven]

I sure am glad I have no idea what y'all are talkin' about.:rolleyes: