North American customers beware of Chinese power cords.

[themadhippy]

About the only thing stamped on a chinese product you can trust to be genuine is "made in china"

[dobsonr741]

If at least one person changes his mind and breaks the “buy cheap from China” addiction then this thread achieved something.

[james_s]

P.S. I believe the North American equivalent is Phase and Neutral, (or Phase and Phase for 230V outlets) but I might be wrong there.

Hot and Neutral typically. "Phase" might be used in industrial settings where you typically have 3 phase power but you don't often see that in a residential application.

[MrAl]

The Chinese have no ehtics, copy anything to make money,  including trademarked safety symbols, CE, UL, VDE, TUV.

Nothing printed or claimed on a Chinese product has any credence including  safety/PFC/EMI  regulation or compliance testing.

 Jon

Haha.  Just to be a bit more PC, i think the right way to state this is to just say that they are ethically challenged (chuckle).

I was really just wondering if this particular product followed that trend or they just ignored it altogether.  If they ignored it altogether it would be easier to prove that it is unfit for sale in this country.

[MrAl]

About the only thing stamped on a chinese product you can trust to be genuine is "made in china"

Ha ha, well put 

[dobsonr741]

Just in case - Product Incident Reporting: https://www.ul.com/resources/market-surveillance-departments

“The following are examples of what should be reported:
- Fire, shock or other personal injury or property damage allegedly caused by UL certified products
- Misuse or misrepresentation of a UL Mark
- Noncompliance with UL Solutions requirements for that product
- Unauthorized or counterfeit UL Marks
- Inappropriate or unauthorized reference(s) to UL Solutions on packaging, web sites, brochures or ads”

[james_s]

It's pretty much futile the way things stand currently. You could play whack a mole reporting products until your life expires through natural causes without making a dent.

[helius]

P.S. I believe the North American equivalent is Phase and Neutral, (or Phase and Phase for 230V outlets) but I might be wrong there.

Hot and Neutral typically. "Phase" might be used in industrial settings where you typically have 3 phase power but you don't often see that in a residential application.

On 230V equipment it is L1, L2, and N. 115V only needs L1 and N. Of course vernacularly electricians and everybody else does call L1 "hot" or sometimes even "phase" but the latter is kind of affected I think.

[Watth]

There are several standards for sockets in EU. cf. https://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#CEE_7_standard
For example, for earthed sockets an plugs:
German's standard (Schuko" or type F) is symmetrical, therefore allows to switch live and neutral.
French standard (Type E) has a protruding prong for earth that makes the socket and plugs asymmetrical, ensuring a proper live/neutral separation.

[AndyBeez]

About the only thing stamped on a chinese product you can trust to be genuine is "made in china"

Although these days North Korea, Vietnam and Cambodia are sources for officially made in the PRC products; especially stuff with high labor inputs and very low western retail prices. Chinese factory workers now expect to be paid fair wages, wtf?

Quality power adapters from somewhere inside the cheena republic, via a Sydney dumpster: EEVblog 1526 – I put 283 Double Adapters in Series with a 2kW Load!
https://www.eevblog.com/2023/01/30/eevblog-1526-i-put-283-double-adapters-in-series-with-a-2kw-load/

[jmelson]

In North America 240V circuits are fused and switched on both sides because both sides are live 120V to neutral with a split phase system.

This fusing concept is curious. The fuses don't always blow both at the same time, right? If one of the fuses is blown, the second wire will still remain live. What's the point of fusing both then?

If fuses are used, they protect the WIRING from a fault to ground.  If the device has developed an internal short, it could be from either line side, or both.
In general, ALL 240 V loads should have linked dual pole breakers in the power panel, so both hots should be interrupted when either pole trips.
Yes, in the special case of a hard fault on one pole of a 240 V load, and a fused panel, if one fuse opens, it could cause the unit to run on 120 V from the non-blown fuse side through the short.  But, fuse panels are going to be QUITE rare in the US today.  I have not run across even ONE in the last 30 years or so.  And, I've been in older buildings with corner-grounded open delta service, but that still had breakers.  I'd guess that power install dated to the 1950's.
Jon

[jmelson]

It's pretty much futile the way things stand currently. You could play whack a mole reporting products until your life expires through natural causes without making a dent.

My mother in law had a cheap power strip.  It had a UL marking on it.  If you turned it upside down, the plugs would fall out, even though it was new.  I reported it to UL as a probably fraudulent UL marking.  I never heard back from them.
Jon

[themadhippy]

If fuses are used, they protect the WIRING from a fault to ground.

You must have some clever fuses in your location,are they smart fuses? ,over here they couldn't  care less how that over current happens, a fault to earth,a fault between phase and neutral ,a fault between phases or just some numskull using the wrong sized device will all result in the same thing,the need to reset/replace the fuse.

[floobydust]

The Chinese have no ehtics, copy anything to make money,  including trademarked safety symbols, CE, UL, VDE, TUV.

Nothing printed or claimed on a Chinese product has any credence including  safety/PFC/EMI  regulation or compliance testing.

 Jon

We allow these products into our countries, all the while it kickstarts their industries because they can make and sell junk. With no consequences or legal path to the offenders.
The West is to blame as well in allowing this to continue.

Last time I went through UL reporting an unsafe product, it ended up the safety standard had no spec for hot running parts, a resistor at 85°C was acceptable. After a few years, it looked quite bad burned phenolic and there is no fuse in the product, so I put in the complaint - but the specific safety standard ignored these requirements common in other safety standards. It was an old UL product-specific standard.

To argue with UL, you'd have to pay for a copy of the standard and since they had already certified the product - meaning the error was on their part- it gets the cover up.
Many Western companies are importing cheap stuff from china, putting a brand name and minimal or fake safety approvals, reselling it for profit.

[ejeffrey]

In North America 240V circuits are fused and switched on both sides because both sides are live 120V to neutral with a split phase system.

This fusing concept is curious. The fuses don't always blow both at the same time, right? If one of the fuses is blown, the second wire will still remain live. What's the point of fusing both then?

We have either hot-hot-ground or hot-hot-neutral-ground.  Either side can develop a hot to neutral or ground fault.  GFI circuit breakers are not universal although they are being required in  more and more places there is a very long tail of circuits that dont have it.  So really in NA you *need* to fuse both legs of any grounded or neutral using equipment that runs off of 208/240 otherwise the fuse isn't doing anything useful.  It's the same as fusing all three phases of a three phase system.

If you have GFI and no neutral wire then you can probably use a single fuse to protect against phase to phase faults and rely on the GFI for phase to ground, but unless you build that into your equipment it's not guaranteed in the US.  Double insulated equipment can also use a single fuse because there is only a single fault path.

[james_s]

Last time I went through UL reporting an unsafe product, it ended up the safety standard had no spec for hot running parts, a resistor at 85°C was acceptable. After a few years, it looked quite bad burned phenolic and there is no fuse in the product, so I put in the complaint - but the specific safety standard ignored these requirements common in other safety standards. It was an old UL product-specific standard.

To argue with UL, you'd have to pay for a copy of the standard and since they had already certified the product - meaning the error was on their part- it gets the cover up.
Many Western companies are importing cheap stuff from china, putting a brand name and minimal or fake safety approvals, reselling it for profit.

A resistor running at 85C doesn't strike me as a big problem, it's common for them to be spec'd to higher operating temperature than that. Yes it will eventually cook cheap phenolic PCB, but it's not going to start a fire.

[richnormand]

If you need another reason not to trust power cords from China look at this thread:

https://www.eevblog.com/forum/chat/fake-power-cord-why-it-came-with-a-hard-drive-reader-kit/

A three prong cord that looks standard but does not have a ground wire connected to the ground pins....   
Next time you go rummaging in your power cord box to connect an instrument that requires a ground for safe operation don't forget to x-ray it for safety if it comes from China.... err a simple ohmmeter check will do I guess but it wont help the undersized wires though.

[shapirus]

err a simple ohmmeter check will do I guess but it wont help the undersized wires though.

this is why I usually bring my milliohmmeter to the pickup point to check the cables before paying for them.

[Watth]

err a simple ohmmeter check will do I guess but it wont help the undersized wires though.

this is why I usually bring my milliohmmeter to the pickup point to check the cables before paying for them.

Just push a dozen amps through the earth wire and ask a trusting friends if it feels hot.

[floobydust]

A resistor running at 85C doesn't strike me as a big problem, it's common for them to be spec'd to higher operating temperature than that. Yes it will eventually cook cheap phenolic PCB, but it's not going to start a fire.

The 24/7 hot running resistor from mains blackened the phenolic PC board, cooked the parts next to it and eventually started smoking. The heat degrades the plastics as well. After a few years, the components are roasted in a bad way.
No fuse, so I hit the horn on that cheap ass chinese junk as any EE would do, sent it off expecting UL would have a finding. The UL product-specific safety standard only cared if the thing worked or not (which it did). Other standards have requirements for a fuse, component temperature testing etc. It did not call any of those standards, which IMHO it should.
Many of the UL standards are quite old going back to the early 1920's like the one for soldering irons. They have accumulated wisdom but fail to update them, and then harmonized standards (IEC) are a second, competing set. It does make a mess. Manufacturers will certify to a lax, old standard whenever possible.

UL can only issue a "warning" about a counterfeit UL mark i.e. https://www.ul.com/news/public-notices they are only concerned protecting their brand name.
UL 817 Standard for Cord Sets and Power-Supply Cords USD $800 plus subscription costs.
The irony of the chinese aggregating all safety standards and posting them for free, whereas you or I can't look at them in order to highlight any shortcoming, is another crime.

It's a massive problem to allow unsafe, fake certified products into your country. The certification agencies have their own ecosystem profiting from test services, approvals, selling standards. It adds a massive burden to SME and does nothing to stop junk from coming in at our ports.

[MrAl]

Hi,

As a rule i always use resistors at 1/2 their rated power or even less.  They can get really, really hot if run at higher power.
You can definitely cook eggs on the 10 watt power resistors if the resistors are powered more than about 1/2 their rated power.
If you run one up using a power supply, you can find out fast, just watch your fingers you won't want to touch one.

[james_s]

Hi,

As a rule i always use resistors at 1/2 their rated power or even less.  They can get really, really hot if run at higher power.
You can definitely cook eggs on the 10 watt power resistors if the resistors are powered more than about 1/2 their rated power.
If you run one up using a power supply, you can find out fast, just watch your fingers you won't want to touch one.

Just taking this example of a ceramic power resistor series: https://www.vishay.com/docs/30216/cpwcpwn.pdf

The max rated operating temperature from the datasheet is 275C, so yes, resistors will run very hot at full rated power.

[floobydust]

Power resistor specs are out to lunch. Those temps are completely unrealistic because the FR-4 gets heated up, as well as any parts nearby especially plastic. Noobs think a "3W" part can do 3W. I have looked at dozens to correlate physical size verses "the spec" because they are literally 1/2 the size they used to be and defying the laws of thermodynamics lol.

For power cords, the chinese Walmart DVD player with <20AWG cheapola power cord Intertek certified, looked terrible. I'm not sure how the IEC standard allows a "6A" rated 20AWG 0.5mm² cord to be connected to a 15A branch circuit. It seems like something to melt and burn up when overloaded. Unless the DVD player's internal fuse is purported to cover that. But IEC power cords can get mixed up, a 6A cord on a 15A appliance. That is another known trap I believe.

[james_s]

Resistors like that are typically not mounted directly to the PCB, they stand up on wide metal leads an inch or more above the board. I still wouldn't want to run one at >200C, but 100-150C is not unreasonable.

[jfiresto]

... For power cords, the chinese Walmart DVD player with <20AWG cheapola power cord Intertek certified, looked terrible. I'm not sure how the IEC standard allows a "6A" rated 20AWG 0.5mm² cord to be connected to a 15A branch circuit....

Do they? I just checked one hundred (100) Europlug cords from various manufacturers, which may be used on 16A 230VAC circuits. They all have 2 x 0.75mm² conductors, even though the plug is only meant to carry up to 2.5A.