RC approved power strip/non surge protector

[karl_nj]

On 8/3/2022 at 3:07 PM, Tolkmit said:

 

USB is just a type of plug, when you are talking about power boards. It doesn't matter what type of plug it is. American standard (A or B) European standards (C, l, or G) or USB plugs... they are all just plugs; one plug into multiple plugs equals power board.

 

 

 

I really think you are stretching things there.  A USB charging hub is not a device multiplying the number of AC electrical outlet, potentially overloading the electrical circuit.  It's a charging device that converts mains AC power to low voltage DC.  It doesn't matter how many USB ports are on it.  OEM vendors of laptops (such as apple) ship their laptops with chargers that can have more than one USB port on it.  Under your "guideline" those would also not be permitted onboard.

 

A power strip/board might also have USB outlets on it, but I would say it's incorrect to call a charger that only has USB outlets a power strip/board.  

 

I wold agree that a USB hub/charger that has a AC passthru or two is in that grey area that is probably best to avoid.

 

[westom]

10 hours ago, rudeney said:

 

What rules are you quoting?  is this a maritime electrical code?  

Read NEMA standards.

[westom]

12 hours ago, chengkp75 said:

Even a power strip with a "circuit breaker" only opens the "hot" leg, which does not fully address the problem of overloading due to the neutral on the ship not being at the same voltage as the ground, ...

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.

[chengkp75]

26 minutes ago, westom said:

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.

Why does a power strip need a 15 amp breaker, when the outlet it is plugged into is protected by a 15 amp breaker upstream of the outlet?  Also, what is the NEMA standard for power strips, a quick look didn't locate one, truly curious.

[Jersey42]

2 hours ago, chengkp75 said:

Why does a power strip need a 15 amp breaker, when the outlet it is plugged into is protected by a 15 amp breaker upstream of the outlet?  Also, what is the NEMA standard for power strips, a quick look didn't locate one, truly curious.

I was curious too, so I did some internet searches.  Here is what I found for the USA. 

My conclusions are based on those searches.

• I could not find a NEMA standard for power strips and I doubt there is one.  NEMA does of course specify the standards for the outlets contained on the power strips.
• UL1363 Standards for "Relocatable Power Taps" provides the standard.  Yes, that is what they are called (RPT). From what I can tell, "Relocatable power taps may also include fuses or other supplementary overcurrent protection", but there is no requirement to have one. I am not curious enough to purchase the full standard document, but see https://www.ul.com/news/electrical-systems-and-equipment-safety
• By the way, UL 1363A often comes up in searches, but this is for hospital grade equipment. I'm not sure if there is a overcurrent protection requirement for hospital situations.
• The National Fire Protection Association also addresses RPTs. Section 11.1.4 of NFPA 1 is the pertinent document.  Prior to 2018 it said "Relocatable power taps shall be of the polarized or grounded type with overcurrent protection and shall be listed". The new text says "Relocatable power taps shall be listed to UL 1363, Standard for Relocatable Power Taps . . .".  So overcurrent protection is removed from the requirements and we are back to UL 1363.  This link shows the changes on page 21:   https://www.nh.gov/safety/divisions/firesafety/documents/NFPA-1-2015-to-2018-changes.pdf
• Many state (and local) fire codes that I have seen still require overcurrent protection. 
• So why do some fire codes require a breaker in the RPT if there is a breaker upstream of the outlet? A Minnesota blog from last year probably offers the simplest explanation.  It is all about the cord from the power strip to the outlet. https://dps.mn.gov/divisions/sfm/for-fire-departments/sfmd-newsletter/Pages/Multi-plug-adapters.aspx

Edited August 7, 2022 by Jersey42

[chengkp75]

I'm aware of UL1363, and its limitations on shipboard applications.

44 minutes ago, Jersey42 said:

So why do some fire codes require a breaker in the RPT if there is a breaker upstream of the outlet?

Probably the main reason that the codes require a breaker on the RPT (was aware of the name as well), is that even a "15 amp" outlet, as a NEMA approved outlet, is allowed to be used for both 15 amp and 20 amp circuits, so the upstream breaker could be a 20 amp breaker, and the cord for the RPT is only rated for 15 amps.

[rudeney]

19 minutes ago, chengkp75 said:

I'm aware of UL1363, and its limitations on shipboard applications.

Probably the main reason that the codes require a breaker on the RPT (was aware of the name as well), is that even a "15 amp" outlet, as a NEMA approved outlet, is allowed to be used for both 15 amp and 20 amp circuits, so the upstream breaker could be a 20 amp breaker, and the cord for the RPT is only rated for 15 amps.

 

Per NEC, an extra breaker is not required unless the device is hardwired.  For example, you have a 20amp circuit in your kitchen, but you likely plug in small appliances (blenders, etc.) that have cords only rated for 15amps.  That appliance does not need its own circuit breaker, but yes, if it shorted and pulled more than 15amps but less than 20amps, it could catch fire and the circuit's 20amp breaker would not trip.  An example of where additional breakers are required is when you have two AC compressor/condenser units on the same circuit.  They each may require 30amps, so you run a single 60 amp circuit to them.  That's acceptable but only if the each have a 30amp breaker where the 60amp feed is split to them.  The idea that a power strip or any other device that provides multiple receptacles requires its own circuit breaker makes no sense.  And neither UL or the NEC have any rules for that.  

[westom]

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.

 

[westom]

7 hours ago, chengkp75 said:

... so the upstream breaker could be a 20 amp breaker, and the cord for the RPT is only rated for 15 amps.

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.

Edited August 8, 2022 by westom

[chengkp75]

25 minutes ago, westom said:

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.

Sorry, not correct.  The safest power strip on a cruise ship is a European 220v power strip, whether plugged into 220v or 110v outlet, with a circuit breaker that interrupts both legs.

Edited August 8, 2022 by chengkp75

[chengkp75]

On 8/5/2022 at 6:28 PM, westom said:

So a power strip must have a 15 amp circuit breaker. 

 

22 hours ago, rudeney said:

What rules are you quoting?  is this a maritime electrical code?  

 

11 hours ago, westom said:

Read NEMA standards.

 

25 minutes ago, westom said:

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. 

So, which is it?  "A power strip must have a circuit breaker, that we are supposed to learn from reading "NEMA standards", or "NEMA does not require a circuit breaker"?

[westom]

11 hours ago, chengkp75 said:

 

 

 

So, which is it?  "A power strip must have a circuit breaker, that we are supposed to learn from reading "NEMA standards", or "NEMA does not require a circuit breaker"?

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.

[westom]

11 hours ago, chengkp75 said:

The safest power strip on a cruise ship is a European 220v power strip, whether plugged into 220v or 110v outlet, with a circuit breaker that interrupts both legs.

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.

 

[chengkp75]

41 minutes ago, westom said:

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.

 

While this is true for land based situations, it is really required for marine installations.  As I've said, that breaker, if it does not interrupt the neutral leg, you can get an amount of current flowing between neutral and ground that is not regulated, except by the upstream, hard wired breaker, whatever its rating is.

 

47 minutes ago, westom said:

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).

No, we're discussing maritime installations, which use 440v, 220v and 110v.

[westom]

22 hours ago, chengkp75 said:

While this is true for land based situations, it is really required for marine installations.  As I've said, that breaker, if it does not interrupt the neutral leg, you can get an amount of current flowing between neutral and ground that is not regulated, except by the upstream, hard wired breaker, whatever its rating is.

 

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.

 

[chengkp75]

8 minutes ago, westom said:

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.

 

I am not talking about a short circuit.  You still don't seem to understand that the "neutral" leg (and there really isn't one in marine electricity) and "ground" are not at the same potential, and that even if the breaker on the power strip cuts the "hot" leg, if there is an insulation failure of an appliance plugged into the power strip, current will still flow from the "neutral" leg to ground, at 60v.

 

Are you saying that residential circuit breakers won't trip on a long, excessive current, that is only a small amount above the rated trip?  I beg to differ, as residential breakers use a class C trip curve, which will trip at about 2 times rating in 100 seconds.  Nearly all breakers will trip over time, at low over rating current, and will trip instantaneously at high over rating current.

[westom]

10 hours ago, chengkp75 said:

I am not talking about a short circuit.  You still don't seem to understand that the "neutral" leg (and there really isn't one in marine electricity) and "ground" are not at the same potential, and that even if the breaker on the power strip cuts the "hot" leg, if there is an insulation failure of an appliance plugged into the power strip, current will still flow from the "neutral" leg to ground, at 60v.

 

 

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.

 

 

[rudeney]

1 hour ago, westom said:

 

 

But again - two completely different anomalies: a short circuit and an overload.

 

 

They are the same thing.  A short circuit is just an infinite amount of overload (i.e. divide by zero)

[chengkp75]

8 hours ago, westom said:

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.

And, again, I am not talking about an insulation failure between wires, I'm talking about a failure between one wire and the case of the appliance.  You stated that "the safest power strip" had a single pole breaker inside it.  I said, that the "safest power strip" for a ship has a dual pole breaker, because even if you interrupt the hot leg, you could still have potential stray current flowing to the case from the neutral leg, as has been found with typical commercial power strips on ships causing fires (there is a USCG safety notice regarding this) because the neutral leg continued to conduct.  I won't continue to  argue whether a power strip breaker has a faster trip curve than a molded case breaker, but a dual pole breaker on the power strip is still safer than a single pole one, due to ship's grounding system.

[ALWAYS CRUZIN]

There are powef strips that are nothing more than a very short (1' or less) extension cord. No breaker nothing. These are acceptable.

[westom]

3 hours ago, ALWAYS CRUZIN said:

There are powef strips that are nothing more than a very short (1' or less) extension cord. No breaker nothing. These are acceptable.

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.

 

[chengkp75]

8 minutes ago, westom said:

Any power strip without protector parts is acceptable to cruise ships.

Actually, this is not correct, either.  RCI does not allow any extension cords, or are you going to debate that a power strip is not an extension cord?

[westom]

On 8/10/2022 at 3:56 PM, chengkp75 said:

Actually, this is not correct, either.  RCI does not allow any extension cords, or are you going to debate that a power strip is not an extension cord?

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.

 

 

 

[westom]

On 8/9/2022 at 9:41 PM, rudeney said:

They are the same thing.  A short circuit is just an infinite amount of overload (i.e. divide by zero)

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.

Edited August 14, 2022 by westom