westom

An overload can be 19 amps on a power strip. Overload is by many appliances doing what they were designed for. A short circuit is a massive current limited only by the conductors that connect a short to a generator. Those same wires, that may be overloaded by 19 amps, can also be conducting well over 100 amps during a short circuit. 19 amps clearly is not a short circuit, Two completely different anomalies. An overload and a short circuit are both excessive currents. With different parameters. Another example of why honesty must include perspective - numbers. Only the least educated make declarations without saying why, without any citation, and without numbers. You make that glaring mistake constantly. Your statement is a soundbite. A tweet - less than 140 characters. Another fact that indicates a lie. Please learn how to know something long before posting emotions.

Extension cord is clearly not a power strip. Extension cords are only for temporary service. Relocatable power taps (also known as power strips) do not have fire code restriction. Because they are completely different. Some jurisdictions define 'temporary' for an extension cord as 30 days. Relocatable power taps are listed for safe use in the National Electrical code. And then an obvious difference. Extension cord does not even have a circuit breaker or fuse. Safest power strips always have that 15 amp circuit breaker. Please learn basic facts before making conclusions or accusations. You have but again made a statement based only in your feelings. By not first learning facts, citations, and numbers. You do this constantly.

Any power strip without protector parts is acceptable to cruise ships. Since those protector parts are a too common reason for fires - aboard ship or in a house. Informed consumers also want that 15 amp circuit breaker for increased (sufficient) safety. Considered so necessary that most all power strips (even those with protector parts) come with that circuit breaker (or fuse). As stated multiple times, a cruise ship does not demand that 15 amp breaker. But will confiscate what seriously increases threats to human life - tiny joule protectors.

When insulation fails - anywhere after that dual breaker - hot to neutral, hot to ground, neutral to ground - then a short circuit exists. Device that must detect and disconnect it is that dual breaker. In seconds. That breaker can trip anywhere from a second to two hours. An overload created by too many appliances would not trip that dual breaker anywhere near fast enough. And need not. Because that power strip must have a 15 amp breaker. That dual breaker can take up to 2 hours to disconnect an overload. A 15 amp circuit breaker in a power strip disconnects an overload much faster - safer. An overload is completely irrelevant to what you keep harping about. Currents flowing due to an insulation failure are a short circuit. That 15 amp breaker also might trip. But a dual breaker back at the panel MUST trip. No matter where (between breaker and appliance) that short circuit (failed insulation) may be. Failed insulation between two wires is a short circuit. Different from another anomaly - an overload. A 15 amp circuit breaker exists, first and foremost, to disconnect an overload, How many times will I say this before you finally read it. Read what is written. A short circuit between any two wires (ie insulation failure) means that dual circuit breaker must trip in a second or less. But it does not trip fast enough for overloads. But again - two completely different anomalies: a short circuit and an overload.

Unfortunately you have conflated two completely different anomalies. That 15 amp breaker on a power strip averts overloadiing. A long and excessive current. That dual breaker that powers the receptacle trips due to a short (ie milliseconds) circuit. A current that well exceeds 60 amps (on a 15 or 20 amp circuit) for a very short time. Two completely different anomalies. That 15 amp breaker in a power strip is not for short circuits. It exists to avert overloading. Short circuits are cut off by that dual circuit breaker.

Since everyone here wants to argue minutia, then let's get the numbers right. European standard is 230v (not 220). North American standard is 120 (not 110). A circuit breaker that interrupts both legs is nice. But does nothing to address the reason for that breaker. Total sum of current to appliances must be less than 15 amps.

Like all standards, a solution both meets and usually exceed standards. NEMA only defines an absolute minimum. Does not define other requirement that also exist for human protection. Is only a minimal requirement. Why argue about a part that costs $2 retail? Solution is so cheap as to almost be irrelevant. And clearly increases protection. Do you not want that 15 amp circuit breaker to decrease human safety? Why? Breaker is a defacto standard. Why argue or deny something so silly? NEMA recommends that circuit breaker or fuse BECAUSE it significantly increases human safety. So it is a defacto standard.. Why is that hard? Best power strip has a 15 amp circuit breaker, no protector parts, and a UL 1363 listing. That simple.

Wires inside walls are grossly oversized by about a factor of four. That 14 AWG (15 amp) wire was once the standard for 20 amp circuits. Even a 20 AWG wire could safely conduct 15 amps. Power cords with 16 AWG wires are safe and sufficient. Wire thickness is not a serious human safety threat. Wires typically are not overloaded. Physical insult is the problem. And is why Arc Fault breakers were created. Meanwhile safest power strip on a cruise ship has a 15 amp circuit breaker, no protector parts, and a UL 1363 listing. Or something equivalent.

Accurately noted is why a 20 amp circuit breaker is more than sufficient for 15 amp receptacles. Those numbers say little about how electricity works. Those numbers are simplified for the benefit of layman. So that 'decision making' is easier. More than 15 amps drawn continuously from a NEMA 5-15 receptacle is a human safety problem. Power eight 100 watt (0.8 amp) incandescent bulbs from that same 15 amp receptacle. More than 60 amps are initially conducted. No problem. Even a 15 amp breaker does not trip. Because those 60 plus amps are not a human safety threat. We simply do not tell consumers everything. Called 15 amps to make it layman simple. Same number also says that 'more than 60 amps' is also safe. NEMA does not 'require' a fuse or circuit breaker. Electrical code is not intended to even discuss such products - not its purpose. But that circuit breaker is strongly recommended. Most power strips (with and without protector parts) have them. An example of why a regulation was not required when an industry implements an effective solution on its own. That does not mean all power strips have that essential 15 amp circuit breaker. UL 1363 (or something equivalent) is also essential for human safety. Hospitals require it. Informed consumers also want it. UL 1449 (something completely different) means a power strip has protector parts that have a nasty habit of creating fires. NEMA and electrical codes are not all requirements. Those are only minimal requirements. Big difference.

That human safety feature (one plug to one receptacle) is compromised when multiple plugs are powered by one receptacle. Does not change the fact that power strips must have a 15 amp circuit breaker.

Read NEMA standards.

All USB ports (from the very first design from Intel) feature a current limiter. That means a typical USB port will never consume more than 0.21 amps. Well below a 15 amp limit. Never matters what one did. Otherwise we can all run stop signs. Since I just ran 10 and never killed anyone. What always matters are facts that predict what is 'safe' and what is 'potentially harmful'. 0.21 amps is not overloading - not a threat.

Go back and reread. First point: Only plug that can mate to that receptacle will always consume less than 15 amps. "Any one plug that can mate to it will never draw more than 15 amps." Second point. Any device that connects multiple plugs to one receptacle must have a 15 amp circuit breaker. "So a power strip must have a 15 amp circuit breaker." Apparently this is new. One does not even begin to grasp something new until a third reread. Even numbers are not seen until a second reading. Please go back and reread it.

Appreciate both problems. First, that receptacle is only rated for 15 amps. Any one plug that can mate to it will never draw more than 15 amps. But a power strip means more than one plug powered by that receptacle. A human safety feature compromised. So a power strip must have a 15 amp circuit breaker. Second issue. Protector parts in a power strip are so tiny (Type 3) that, in a home, it must be more than 30 feet from a main breaker box and earth ground. So that it does not try to do much protection. Otherwise its tiny joules can [do this](http://www.esdjournal.com/techpapr/Pharr/INVESTIGATING SURGE SUPPRESSOR FIRES.doc). Safest power strip has a 15 amp circuit breaker, no protector parts, and a UL 1363 listing. Cruise ships take those two fire threats far more seriously.

Second one might have had a UL Listing. First one did not.

Please learn what any electrician would know. This is a NEMA 5-15 receptacle. It is the most common receptacle found in homes. Connected to a 20 amp breaker. If 'Bad', then all new homes are bad. 14 AWG was once the standard and safe wire for all 20 amp circuits. 12 AWG wire was more recently a standard for 20 amp circuits. Even 18 AWG wire can safely conduct 20 amps. But we use 12 AWG wire - oversized - for other electrical reasons. Not because anything is 'Bad'. 12 AWG is better - for other reasons.. If NEMA 5-15 receptacles were not safe for 20 amp circuits, then NEMA 5-20 plugs must be used. Those look like this. Wire to NEMA 5-15 (15 amp) plug is typically 12 AWG - for 20 amp circuits. Is done because engineers know what is safe and necessary. Apparently wild speculation did not learn basic electrical concepts that say why code powers NEMA 5-15 (15 amp) receptacles from 20 amp circuit breakers and 12 AWG wire. NEMA 5-15 receptacles are typically on 15 amp circuit breakers (and 14 AWG wire) when that circuit only powers one receptacle box. Ie a refrigerator. Decades ago, all 20 amp circuits safely used 14 AWG wire. Back then, all 15 and 20 amp circuits used cable that was white. Yellow for 12 AWG is also new upgrade. One knows this stuff. Another does not.

No higher AC voltage is between two wires. That 120 volt generator does not put 480 volts on cabin receptacles. It is a voltage that peaks that resides at or between 120 volts RMS. If 480 volts between neutral and ground, then 120 volts appliances are potentially damaged. Safety ground is always a voltage located somewhere between the hot and neutral wires. So that appliances and electronics are undamaged. And so that human life is not at risk No 120 volt appliance is safe when a voltage between that appliance, through a human, to ground is 480 volts (peaking at 675 volts). Please stop inventing number that cannot exist - if human safety exists. 'Reverse voltage' is called 'reverse polarity'. Neither wire will be more than 120 volts relevant to safety ground. On ships, that number is typically 60 volts. Meaning protectors should be even safer. Protectors fail due to tiny joules. Not due to a mythical 'reverse voltage'. If doing this stuff as an engineer, then you know why electronics are so robust. First it filters transients on AC mains. Then convert 60 Hz and transients to a DC voltage. Then filters again. Then converts that to radio frequency spikes that exceed 300 volts. Now 'dirtiest' power is inside electronics. No problem. Galvanic isolation, regulators, and more filters convert that 'dirtiest' power into DC voltages that do not vary even 0.2 volts. Best protection at electronics is already inside electronics. Numbers say so. Only if one learns basic electrical and electronics concepts rather than believe hearsay and myths. Type 3 protectors (you did not know what a Type 3 protector is) are a potential fire threat. Cruise ships take that fire threat (demonstrated by examples with numbers that say why) far more seriously. Surges do not use up a semiconductor's life. A surge blows through a transistor's P-N junction - doing damage. Or it is safely consumed as electricity. This "use up some of the life" myth is a classic example of junk science reasoning. "I feel it is true. So it must be true". Show me the engineering paper that describes "use up". I have yet to see it in 50 years of datasheets and application notes doing electronics design. All appliances and all protectors are designed for 0 volts between neutral and safety ground. And for 160 volts between neutral and safety ground. On a ship, that voltage can be above zero and below 120 volts - constantly. Never 480 volts. Protectors are a fire threat due to near zero joules. No way around that specification number. Cruise ships take that fire threat seriously. Obviously many urban myths about ship board wiring are promoted. Without a basic grasp of what appliances and protectors can and cannot withstand. Even a rumored "reverse voltage" is actually called "reverse polarity". Warning to all. Technical lies are rampant. Promoted by people who do not first learn numbers. That 480 volt number is a real doozy.