Author Topic: Two Mysteries of Chinese eBay Products  (Read 755 times)

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Offline Deodand2014

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Two Mysteries of Chinese eBay Products
« on: February 23, 2019, 05:40:50 am »
I have over many years of watching videos tearing down Chinese made eBay products (The super cheap kind.) two consistent things, first, the fuses are fitted to the neutral line rather than the positive. Second no earthing (In the example video below, the earth wire is there and properly crimped, but not connected even though a place had been prepared for it.). Does anyone have any ideas (good ones) why either of these things might be the case.

 

Offline aargee

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Re: Two Mysteries of Chinese eBay Products
« Reply #1 on: February 23, 2019, 06:55:23 am »
I would think absolutely zero need and hence zero interest in safety for unregulated exported products.
Not easy, not hard, just need to be incentivised.
 

Offline ozcar

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Re: Two Mysteries of Chinese eBay Products
« Reply #2 on: February 23, 2019, 07:08:37 am »
I suspect the fuse is not always in the neutral.

This is one of those UV "nail lamps". I confirmed the brown wire coming in is the active. Well, they almost got the fuse in the active. 
 
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Online jfiresto

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Re: Two Mysteries of Chinese eBay Products
« Reply #3 on: February 23, 2019, 07:19:12 am »
... the fuses are fitted to the neutral line rather than the positive....
The Schuko mains plug used by the blue European countries below is unpolarised, so perhaps half the time, the fuse will be on the hot side.





 
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Offline magic

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Re: Two Mysteries of Chinese eBay Products
« Reply #4 on: February 23, 2019, 08:41:54 am »
All the blue and red countries also use these plugs for unearthed equipment: https://en.wikipedia.org/wiki/Europlug

I don't know if it's a good thing or not. On the downside, we can only have global RCDs and many-amp circuit breakers rather than per-device fuses to interrupt line to earth shorts. Unless you put fuses on both lines, which nobody seems to do. On the upside, it very effectively prevents sloppy designers from using earth and neutral interchangeably  :-BROKE
« Last Edit: February 23, 2019, 08:46:22 am by magic »
 

Offline blueskull

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Re: Two Mysteries of Chinese eBay Products
« Reply #5 on: February 24, 2019, 01:44:08 pm »
Just FYI, Chinese 2-pin plugs are NON-POLARIZED, but 3-pin plugs are POLARIZED.

Chinese 2-pin plugs are just NA/JP/TW plugs without the polarized thicker blade, and also without the retention holes. They are SUPPOSED to be compatible (CN 2-pin plugs fit well in US sockets, US non-polarized plugs fit well in CN sockets), but sometimes US plugs get stuck in CN sockets due to the retention holes.

Chinese 3-pin plugs are 100% compatible with AU/NZ plugs, just without the plastic sleeves and unlike everything over there, up side down. They are polarized, with the left side being hot and right side being cold (assuming earth blade is on TOP).

Color coding of Chinese mains cables follow EU IEC/ISO standards, with hot being brown, cold being blue, and striped green/yellow being earth.

Consumer device safety standards in China follow IEC 60950-1, which mandates two layers of safety of a number of combinations. It could be grounding plus basic/standard insulation or reinforced/double insulation, across primary and secondary.

The sequence of line and neutral is not emphasized, as the standard assumes both can be hot and only earth can be trusted. This is essential as certain 220V~240V devices can be used in 100V~120V countries with split 120V supplies, so both are hot with respect to true neutral/earth.
 
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