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Old 18-04-2013, 14:14   #16
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Re: Power strip dangers

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First, to work, a protector adjacent to electronics must either block or absorb surge energy. So view the numbers. If destructive surges are as much as hundreds of thousands of joules, then what do hundreds of joules in that protector do?
huh, thousands of joules typically surges are in the 100 range, ( as they are fast spikes) and MOVs etc can handle about 1000. But hundreds of thousands!!. Many power strips use multiple MOVs to offer about 4000-5000 joules of protection, nut such numbers are actually nonsense.


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Grossly undersized. A protector part must disconnect while leaving the appliance connected to that surge. A thermal fuse (ie 1 amp) must disconnect protector parts as fast as possible. Otherwise a fire can result.
There are two types of SPD, types that go open circuit,and those that short briefly. Note that surge protection is only an add-on, the device connected to the mains should absorb the spike. The SPD cannot protect the device for everything ( say like direct lightening )


The most common transient device used in power strips is the MOV, it does degrade with activation and will eventually short , hence they are ( should be) pared with a thermal fuse, and an indication light . IN reality surge protectors should be binned after one of two "strikes". The risk of fire is poorly designed or over utilised surge circuits is a real one. ( with MOVs). Really they are a one time use part. They are also common in multimeters.


The fuse ( and the indicator light) does not mean the MOV is "grossly undersized" it merely is used to indicate to the user that the MOV has triggered ( and used up a portion of its life). The fuse is there to protect the MOV and it opens if the MOV short circuit current goes on for two long , indicating that the MOV is breaking down at lower voltages.

A new MOV doesn't technically need a fuse, an old one definitely does.

Most surge protected power strips have a light that stays on until the MOV fails , then its garbage.

MOVs are unfortunate in there usage characteristics, they are really one use devices, but often the public doesnt know that.

A power strip with surge protection should always have a indicator light and a thermal fuse protecting the MOV, ( that may not be obvious), unfused MOVs are a fire risk, This is covered in a UL specification. In Europe mandatory compliance with EN 61643-11:2002 demonstrates compliance to the Low Voltage Directive which covers surge protection circuits.

Many surge protection circuits also use a capacitor inductor circuit that doesnt suffer such issues , but is not quite as effective.

report is still gobbidly-gook
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Old 18-04-2013, 14:36   #17
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Re: Power strip dangers

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Originally Posted by zeehag View Post
so, guys, i am willing to take one for the crew..i use mine whenever i wish, usually in marinas where the pout[put is read on a meter to be 137volts....and when i need to use mpre than one outlet in my boat.
i can safely say i never smelled any stink from burning eletricity,nor has my ground fault thingie made any fuss about the circuitry.
my surge protector is mexican and it has ground and reverse polarity lights for alleged safe usage...i like that feature as i have had bad ground from marina in past...at la cruz marina. the strip helped me to find the cause and repair it before fires or stinky smell.
I use one, too. i am extremely careful to not overload it. In fact, for my shore current, i have a power cord directly from shore into my cabin, bypassing my boat's electrical system completely, because it's old and I don't understand electricity. For instance, I use a ceramic space heater on cold nights, but it is powered directly from the marina. I don't have that heavy current draw running through my boat's wires.

Ditto for AC in the summer, as well as my induction cooktop, which probably is low draw, and my little dorm-style refrigerator.

If an EE cannot understand the article, it's not going to be any use to me. There is of course a strong safety bias against power strips because they can encourage people to try to draw more current than their cords can handle. I get that. It can cause fires.

Gotta be careful out there.
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Old 18-04-2013, 14:39   #18
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Re: Power strip dangers

No Zee, there is an issue with the use of MOV based power strips, especially cheap ones. If teh MOV is not protected by a fuse then problems can arise , right up to miniature explosions and fire

Get good ones and monitor the light etc.


As to the report , I was merely commenting on the techno-garbage it rambled on about. I still dont know what they mean.
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Old 18-04-2013, 15:01   #19
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Re: Power strip dangers

I'm only speculating to what the author of the alert had intended to say, because as others have mentioned......it's unintelligible babble.

I think, being a us flagged ship, it would have a hot and a neutral on a 110vac circuit. Now if I'm reading correctly, it sounds like another circuit was creating voltage on the neutral (say a leak from another leg .................................Never mind, the more I try to reason through it, it makes even less sense.
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Old 18-04-2013, 21:35   #20
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Re: Power strip dangers

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Originally Posted by Rakuflames View Post
If an EE cannot understand the article, it's not going to be any use to me.
This EE has generations (not just decades) of experience in this topic. Parts of that report are correct IF we add facts apparently not provided by that report.

Another did not get it. Overloading a power strip is completely irrelevant. The topic is about a transient that threatens human life in a house. And is more dangerous in vessels.

Even a cheap power strip verses expensive one is irrelevant. Read manufacturer spec numbers. A power strip selling in WalMart for $10 is similar to a power strip sold by Monster for $100. Monster knows most are so uninformed as to assume expensive paint and a higher price means better quality. Worse are some who assume a better warranty means a better product. Reality. A better warranty is usually found on more inferior products.

Know where hundreds of thousands of joules dissipate. If a transient is hundreds of joules, then protection already inside all electronics makes that transient irrelevant. Your concern is a transient that can overwhelm superior protection already inside appliances.

MOVs must be protected by a "thermal" fuse. That fuse is completely different from another fuse or circuit breaker that must also exist on every power strip - protector or non-protector type. A non-thermal fuse is for overloads. We were never discussing overloads. An always useful answer also provides numbers. Separate useful post from speculation by demanding numbers - especially spec numbers.

Protectors adjacent to appliances have a rare but nasty habit of causing fires. Examples are numerous. This poster woke up to find a protector created fire. Fortunately, fire cause his aquarium to bust. Fish and water extinguished a fire. From Whitneyd88 on 21 Mar 2011 entitled "My house caught on fire and my tank busted":
> A plug caught fire in my room (which was plugged into a surge protecter)
> it was caused by a power surge and caused my tank to burst.

If a protector is effective, then you can say (even using manufacturer numbers) where hundreds of thousands of joules dissipate. Demand spec numbers from every recommendation.

Coast Guard apparently describes a transient that the power strip is not designed to avert. And that, in some cases, causes a fire if the only remaining human protection device (a thermal fuse) does not disconnect protector parts.

That risk should have everyone's attention when a vessel is involved. A problem especially problematic when a protector is connected directly to shore power without some other completely different device - also called a surge protector. Or when an inferior generator create excessive spikes.

Adjacent power strip protectors have a nasty history of creating fire. But then its few hundred joules will do what? Again, always required spec numbers. No numbers is how myths (or fires) get created. Where would hundreds of thousands of joules dissipate without damage? An answer is only found in effective protection. But again - numbers.

A protector light only reports a protector was so grossly undersized that the thermal fuse had to blow to protect human life. Light does not report other failures. A properly sized protector does not fail - even with a direct lighting strikes. That should have everyone's attention. Because that hard fact is contrary to popular urban myths. Because the solution often costs less money. And made obvious by manufacturer spec numbers.

Even MOV degrading (failure) means fire if its thermal fuse does not trip out fast enough. Completely different from another and always required 15 amp breaker.
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Old 18-04-2013, 21:45   #21
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Re: Power strip dangers

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Originally Posted by westom View Post
This EE has generations (not just decades) of experience in this topic. Parts of that report are correct IF we add facts apparently not provided by that report.

Another did not get it. Overloading a power strip is completely irrelevant. The topic is about a transient that threatens human life in a house And is far more dangerous in vessels.

Even cheap power strip verses expensive ones is obviously irrelevant. Read manufacturer spec numbers. A power strip selling in WalMart for $10 is similar to a power strip sold by Monster for $100. Monster knows most are so uninformed as to assume expensive paint and a higher price means better quality. Worse are to many who assume a better warranty means a better product. Reality. A better warranty is usually found on the most inferior products.

Know where hundreds of thousands of joules dissipate. If a transient is hundreds of joules, then protection already inside all electronics makes that transient irrelevant. Your concern is a transient that can overwhelm superior protection already inside all appliances.

MOVs must be protected by a "thermal" fuse. That fuse is completely different from another fuse or circuit breaker that must also exist on every power strip - protector or non-protector type. The non-thermal fuse is for overloads. We were never discussing that. The always useful or honest answer also provides numbers. Separate useful post from speculation by demanding numbers - especially spec numbers.

Protectors adjacent to appliances have a rare but nasty habit of causing fires. Examples are numerous. This poster fortunately woke up to find a protector created fire. Fortunately, fire cause the aquarium to bust. Fish and water extinguished the fire. From Whitneyd88 on 21 Mar 2011 entitled "My house caught on fire and my tank busted":
> A plug caught fire in my room (which was plugged into a surge protecter)
> it was caused by a power surge and caused my tank to burst.

If a protector is effective, then you can say (even using manufacturer numbers) where hundreds of thousands of joules dissipate. Demand such numbers from every recommendation.

Coast Guard apparently describes a transient that the power strip is not designed to avert. And that, in some cases, causes a fire if the only remaining protection device (a thermal fuse) does not disconnect protector parts. And leaven the appliance connected.

That risk should have everyone's attention when a vessel is involved. A problem especially problematic when a protector is connected directly to shore power without some other completely different device also called a surge protector. Or when spikes generated by an inferior generator causes those spikes.

Adjacent power strip protectors have a nasty history of creating fire. But then its few hundred joules will do what? Again, always required spec numbers. No numbers is how myths (or fires) get created. Where would hundreds of thousands of joules dissipate without damage?

A protector light only reports the protector was so grossly undersized that the thermal fuse had to blow to protect human life. Light does not report other failures. A properly sized protector does not fail on any surge - including direct lighting strikes. That should have everyone's attention. Because that hard fact is contrary to popular urban myths. And made obvious by reading manufacturer specs.

Even MOV degrading (failure) means fire if its thermal fuse does not trip out fast enough. And again, that is completely different from the other and always required 15 amp breaker.

As I said before, I know very little about electricity. Can you tell me what kind of surge protector I should have on the shore power? Would it go between the shore power post and the cord? Or at the other end of the cord? This kind of help is immeasurable.
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Old 18-04-2013, 22:20   #22
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Re: Power strip dangers

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Originally Posted by Rakuflames View Post
Can you tell me what kind of surge protector I should have on the shore power? Would it go between the shore power post and the cord?
No protector addresses every anomaly. But a 'miracle' protector is sold to do just that. First define which anomaly must be solved.

For example, a rare but so destructive anomaly occurs when lightning strikes AC wires on utility poles. That current hunts for a best path to earth. One such path may be destructively through marina power, through a boat, and into water.

Most who recommend protectors assume it will somehow stop or absorb a surge. No protector does that. Obvious if spec numbers are read. Protection means connecting a surge to earth (or water) before it enters the boat. Useful protection means that transient current in not entering and passing through boat electronics.

How many wires (in a power cable) enter a boat? Three? Four? Protection means every one connects to earth BEFORE connecting to the boat. Some (ie neutral) already make that connection. Others (hot) must make a low impedance (ie 'less than 10 foot') connection to earth via a protector.

Effective protectors connect short to earth. Nothing stops or blocks that surge. Well proven protection means another type protector connects transients direct (and as short as possible) to earth (or water).

For protection at the marina, a 'whole house' protector from more responsible companies is required. Names include Intermatic, Cutler-Hammer, Square D, General Electric, Ditek, ABB, Siemens, Polyphaser, or Transtector. All names that any guy knows for integrity. Clearly not listed are devices that magically stop or absorb surges such as Belkin, APC, Tripplite, etc.

Now, let's move on to a completely different anomaly apparently described by the Coast Guard. No power strip protects from that. And can sometimes cause a fire (as described previously). Best protection from that anomaly is appliances designed with a universal power supply. Operates on any voltage from 85 to 265 volts. All portable appliances do that. Others are available. Then that completely different anomaly is made irrelevant.

Now, which anomaly concerns you? Scams are promoted when one protector magically protects from all anomalies. No protector does that. Described are two completely different anomalies. Which one concerns you? Each anomaly has a completely different solution.
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Old 18-04-2013, 23:24   #23
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Re: Power strip dangers

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Originally Posted by westom View Post
No protector addresses every anomaly. But a 'miracle' protector is sold to do just that. First define which anomaly must be solved.

For example, a rare but so destructive anomaly occurs when lightning strikes AC wires on utility poles. That current hunts for a best path to earth. One such path may be destructively through marina power, through a boat, and into water.

Most who recommend protectors assume it will somehow stop or absorb a surge. No protector does that. Obvious if spec numbers are read. Protection means connecting a surge to earth (or water) before it enters the boat. Useful protection means that transient current in not entering and passing through boat electronics.

How many wires (in a power cable) enter a boat? Three? Four? Protection means every one connects to earth BEFORE connecting to the boat. Some (ie neutral) already make that connection. Others (hot) must make a low impedance (ie 'less than 10 foot') connection to earth via a protector.

Effective protectors connect short to earth. Nothing stops or blocks that surge. Well proven protection means another type protector connects transients direct (and as short as possible) to earth (or water).

For protection at the marina, a 'whole house' protector from more responsible companies is required. Names include Intermatic, Cutler-Hammer, Square D, General Electric, Ditek, ABB, Siemens, Polyphaser, or Transtector. All names that any guy knows for integrity. Clearly not listed are devices that magically stop or absorb surges such as Belkin, APC, Tripplite, etc.

Now, let's move on to a completely different anomaly apparently described by the Coast Guard. No power strip protects from that. And can sometimes cause a fire (as described previously). Best protection from that anomaly is appliances designed with a universal power supply. Operates on any voltage from 85 to 265 volts. All portable appliances do that. Others are available. Then that completely different anomaly is made irrelevant.

Now, which anomaly concerns you? Scams are promoted when one protector magically protects from all anomalies. No protector does that. Described are two completely different anomalies. Which one concerns you? Each anomaly has a completely different solution.

Sigh. I really don't understand all of this. I'm 67, female, and started sailing in at age 64. I've had a LOT to learn in addition to sailing -- diesel engines, etc.

I need to be told what's the best bet for me. I don't own the marina, and won't be installing any kind of systemwide protection. if that's possible. If not, I'll continue as I am, which I still believe is better than pulling large amounts of power through old wiring.
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Old 19-04-2013, 15:56   #24
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Re: Power strip dangers

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Originally Posted by Rakuflames View Post
I need to be told what's the best bet for me. I don't own the marina,
Nobody can say more because you have not defined what currently exists. Does shore power connect to your boat? You don't specifically say. And say how.

Forget old wiring or new. Both are similar. Forget about drawing large amounts of AC power or little. That also was defined previously as irrelevant here.

Relevant was taught in elementary school science. What does lightning seek? Protection for shore power is also about an answer to that question.

Coast Guard report is about something completely different. However, in both cases, some foolishly attempt to avert both anomalies using a power strip protector ... that does not claim to protect from either. As if it were a 'magic' box. It has a history, in rare cases, of creating fire. Be concerned if you have not installed or had installed protection necessary to protect that type power strip.

Overloading a power strip (protector or non-protector type) is completely irrelevant to this discussion and the Coast Guard report. We are discussing a problem unique to protector type power strips. A problem not found in non-protector power strips

Again, what does lightning seek to do damage?
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Old 19-04-2013, 18:42   #25
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Re: Power strip dangers

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Originally Posted by Rakuflames View Post
As I said before, I know very little about electricity. Can you tell me what kind of surge protector I should have on the shore power? Would it go between the shore power post and the cord? Or at the other end of the cord? This kind of help is immeasurable.
If you can afford an electrician, or have a knowledgeable friend who will work for dinner or a nice banana-bread, get your boat's AC wiring looked at. Old doesn't necessarily mean bad or dangerous. If it was installed with care and inspection shows the connections are OK, it would be safer to use the boat's AC wiring than relying on extension-cords, splitters and power bars. Especially if you run heaters, hot-plates or other high-draw items.

Also, you don't really need surge protection for the whole boat. There's not alot that defends completely against a direct lightning hit except insurance and luck. For smaller spikes and surges, most AC appliances don't care, and the fussier AC-powered electronics like computers can be protected somewhat with the surge-protector in a good power-bar.
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