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Products => Test Equipment => Topic started by: SNGLinks on April 09, 2015, 09:35:39 am

Title: Red is Negative, Black is Positive in China?
Post by: SNGLinks on April 09, 2015, 09:35:39 am
I have just received a volt/amp panel meter from China.
Attached is the wiring diagram.

I assume Anode is +ve and Cathode is -ve.
I queried it and got the wiring diagram, as shown,  sent to me.

WTF?


Title: Re: Red is Negative, Black is Positive in China?
Post by: amyk on April 09, 2015, 10:01:40 am
No, anode is negative and red is still positive. They just drew the diagram rather confusingly.

Compare:
http://en.wiktionary.org/wiki/%E8%B4%9F (http://en.wiktionary.org/wiki/%E8%B4%9F)
http://en.wiktionary.org/wiki/%E6%AD%A3 (http://en.wiktionary.org/wiki/%E6%AD%A3)
Title: Re: Red is Negative, Black is Positive in China?
Post by: SNGLinks on April 09, 2015, 10:42:26 am
Thanks! Very confusing :)
Title: Re: Red is Negative, Black is Positive in China?
Post by: BurningTantalum on April 09, 2015, 11:51:37 am
They used to have traffic lights that were red for go and green for stop. The last set I saw in 2 years of working there was outside Kunming and they were blue for stop but had been rewired to the international norm in the late 80s, although the red light was still at the bottom.
Knock off NiCad and Nimh cells often have the printed sleeves assembled 'upside down'.
I often saw trucks with two red lights at the front and two white lights at the rear - we then refused to be driven at night.
BT
Title: Re: Red is Negative, Black is Positive in China?
Post by: TimFox on April 09, 2015, 12:53:55 pm
I have seen old (not up to current IEC specs) wiring in Europe where red was "ground" or "protective earth", instead of the present green/yellow, or green in US.
Title: Re: Red is Negative, Black is Positive in China?
Post by: sync on April 09, 2015, 03:57:07 pm
I have seen old (not up to current IEC specs) wiring in Europe where red was "ground" or "protective earth", instead of the present green/yellow, or green in US.
Yes, in Germany red was used for protective earth (1 phase cables) AND for L2 in a 3-phase system.
Title: Re: Red is Negative, Black is Positive in China?
Post by: TimFox on April 09, 2015, 05:50:16 pm
I  have often wondered about the logic behind color-code choices, but using the same color for L2 and PE seems dangerous.
The US standard for "line" in a single-phase system is black, with white for neutral.  An electrician told that was because "black means death", which is presumably the mnemonic they taught him as an apprentice.  As I understand it, the normal US code reserves white for neutral, green for ground/PE, and allows the other colors (including black) for "hot" wires (including switched).
Title: Re: Red is Negative, Black is Positive in China?
Post by: sync on April 09, 2015, 06:12:55 pm
I searched a bit and found that red was also used for switched line voltage. It's not only dangerous. It's completely insane.
Title: Re: Red is Negative, Black is Positive in China?
Post by: electr_peter on April 09, 2015, 06:46:00 pm
Regarding original post, DC wire colours may be misleading in situations where current is measured (because of multiplication of wires). Correct action would be to get a proper manual and/or double or triple check everything with a DMM before powering it up.
Title: Re: Red is Negative, Black is Positive in China?
Post by: SeanB on April 09, 2015, 07:03:10 pm
A small list in easy to understand form.

https://en.wikipedia.org/wiki/Electrical_wiring#Colour_code

Title: Re: Red is Negative, Black is Positive in China?
Post by: AG6QR on April 09, 2015, 07:04:54 pm
I  have often wondered about the logic behind color-code choices, but using the same color for L2 and PE seems dangerous.
The US standard for "line" in a single-phase system is black, with white for neutral.  An electrician told that was because "black means death", which is presumably the mnemonic they taught him as an apprentice.  As I understand it, the normal US code reserves white for neutral, green for ground/PE, and allows the other colors (including black) for "hot" wires (including switched).

This gets especially nasty when standards are mixed.  As you point out, in regular household electric wiring, black is live, white is neutral, and green is ground.  But for DC automotive use, a typical code is that black is negative/chassis, and red is positive.

RVs or camper trailers are a hybrid of a vehicle and a house.  They typically have AC and DC wiring.  The AC is usually like house wiring, black live and white neutral.  The DC is sometimes like automotive, red + and black -, but often it's also black/white, where black is +12V and white is negative ground, connected to the chassis.

When I see a black wire in an RV, I never know whether it is connected to +12VDC, 120VAC, or chassis ground.  Gotta test everything.
Title: Re: Red is Negative, Black is Positive in China?
Post by: SeanB on April 09, 2015, 07:21:42 pm
Work on aircraft, where every wire is white. Can be ground, 28VDC, 115VAC 400Hz, 2kVDC ( nasty to find on the connector, as they are rated for it) or anything in between. Only thing you can be reasonably sure of is the 00SWG wiring will be either ground or 28VDC.
Title: Re: Red is Negative, Black is Positive in China?
Post by: Rick Law on April 10, 2015, 01:31:34 am
They used to have traffic lights that were red for go and green for stop. The last set I saw in 2 years of working there was outside Kunming and they were blue for stop but had been rewired to the international norm in the late 80s, although the red light was still at the bottom.
Knock off NiCad and Nimh cells often have the printed sleeves assembled 'upside down'.
I often saw trucks with two red lights at the front and two white lights at the rear - we then refused to be driven at night.
BT

That was not something "they used to do".  That were changed by the Red Guards during the Cultural Revolution in the 1960's.  As you would expect, in the view of the Red Guards, Red should mean means go.
Title: Re: Red is Negative, Black is Positive in China?
Post by: daybyter on April 10, 2015, 02:24:30 am
When I had to replace the battery of my ti 57 calculator, I had to learn, that red is also negative in Texas... :-)
Title: Re: Red is Negative, Black is Positive in China?
Post by: timofonic on April 10, 2015, 08:31:15 am
When I had to replace the battery of my ti 57 calculator, I had to learn, that red is also negative in Texas... :-)
In Texas and Arizona, red is negative! Or was black too? ;)
Title: Re: Red is Negative, Black is Positive in China?
Post by: mrf245 on April 10, 2015, 08:54:40 am
Of course,RED is positive and BLACK is negivite in your picture(according to Chinese text)
Title: Re: Red is Negative, Black is Positive in China?
Post by: elgonzo on April 10, 2015, 08:58:40 am
When I had to replace the battery of my ti 57 calculator, I had to learn, that red is also negative in Texas... :-)
In Texas and Arizona, red is negative! Or was black too? ;)
Nonsense! Red is the color of the GOP, thus red is very, very positive in Texas and Arizona. ;)
Title: Re: Red is Negative, Black is Positive in China?
Post by: babysitter on April 10, 2015, 10:03:29 am
Black is red and positive is negative, of course.

(Come on you had enough time to pull out this old joke)
Title: Re: Red is Negative, Black is Positive in China?
Post by: Rick Law on April 11, 2015, 12:54:22 am
When I had to replace the battery of my ti 57 calculator, I had to learn, that red is also negative in Texas... :-)

And in accounting departments anywhere in the USA.  Red=negative.

"Seeing Red"=="Big Yikes"

Why is 12Volt so timid?  Because it is always Yellow...
Title: Re: Red is Negative, Black is Positive in China?
Post by: Paul Moir on April 11, 2015, 03:59:02 am
.  As I understand it, the normal US code reserves white for neutral, green for ground/PE, and allows the other colors (including black) for "hot" wires (including switched).

And of course, there's the exceptions.  For example a common switch leg.  This is where you wire power to for example a light fixture's junction box, then drop a 2-wire to a switch to turn it on and off.  Since the 2-wire is white & black, what's an electrician to do? 

The code answer is to connect the switch's white to hot in the fixture's junction box, and connect the black wire to the fixture.  The rational is if the fixture gets changed, the (presumably homeowner) is confronted with a white and black wire to attach to his new fixture, so there is no possibility for confusion.  If the black switch leg wire was made the permanently hot one, the homeowner would see two white wires going to the fixture and so he would be liable to wire the fixture backwards.

The mnemonic that stuck with me was "Down on the white, back on the black."
Title: Re: Red is Negative, Black is Positive in China?
Post by: Chipmunk on April 11, 2015, 04:13:52 am
Here in the UK it's pretty much the exact opposite, on a switch drop, the brown wire will be Live, as normal, and the blue will be the switched live to the fixture (sleeved in brown at each end if the electrician's following the rules). I tend to tape them brown AND sleeve, in case the sleeving falls off
Title: Re: Red is Negative, Black is Positive in China?
Post by: Rick Law on April 11, 2015, 06:21:05 am
Oh boy, this is a bigger mess than I thought.

I fixed my heating system motor last year.  Brown was something I already forgot,  Blue is the the slow fan...  at least the research I did then led me to think it was some kind of standard.

Can color blind electrician even do the job?  What if the same blower fan is taken to Canada?  Would it kill someone when they hook it up according to their standard color scheme.

I wonder if there is a high rate of accidents with electricians who happens to be recent immigrants to a particular country.
Title: Re: Red is Negative, Black is Positive in China?
Post by: TimFox on April 11, 2015, 02:02:47 pm
.  As I understand it, the normal US code reserves white for neutral, green for ground/PE, and allows the other colors (including black) for "hot" wires (including switched).

And of course, there's the exceptions.  For example a common switch leg.  This is where you wire power to for example a light fixture's junction box, then drop a 2-wire to a switch to turn it on and off.  Since the 2-wire is white & black, what's an electrician to do? 

The code answer is to connect the switch's white to hot in the fixture's junction box, and connect the black wire to the fixture.  The rational is if the fixture gets changed, the (presumably homeowner) is confronted with a white and black wire to attach to his new fixture, so there is no possibility for confusion.  If the black switch leg wire was made the permanently hot one, the homeowner would see two white wires going to the fixture and so he would be liable to wire the fixture backwards.

The mnemonic that stuck with me was "Down on the white, back on the black."

Does the code allow adding colored electrical tape to the ends of the white wire in your example?  I am familiar with blue and red tape used on three phase circuits, where the only wire available was black.
Title: Re: Red is Negative, Black is Positive in China?
Post by: Fungus on April 11, 2015, 03:04:02 pm
The people who decided the new "standard" also managed to forget about color-blind people:

http://www.brighthubengineering.com/commercial-electrical-applications/107563-color-blindness-rules-for-electricians-and-electrical-engineers/ (http://www.brighthubengineering.com/commercial-electrical-applications/107563-color-blindness-rules-for-electricians-and-electrical-engineers/)

The best colors would be black/white/stripey. The stripey wire would have to be higher contrast than yellow/green (which doesn't look stripey at all to people who can't see green).


Title: Re: Red is Negative, Black is Positive in China?
Post by: KeepItSimpleStupid on April 12, 2015, 12:51:27 am
I learned early not to trust colors.  In the thermocouple world red is negative.

All white or all black wires were in a commercial instrument.  Turned out they had numbers printed on them.  Motors might too.

The IEC colors blue/brown and green with white, I haven't found a way to remember yet.
Title: Re: Red is Negative, Black is Positive in China?
Post by: videobruce on April 12, 2015, 07:13:09 am
A small list in easy to understand form.
https://en.wikipedia.org/wiki/Electrical_wiring#Colour_code
.
Notice, China is not included.  :-DD
Title: Re: Red is Negative, Black is Positive in China?
Post by: coppice on April 12, 2015, 07:43:04 am
A small list in easy to understand form.
https://en.wikipedia.org/wiki/Electrical_wiring#Colour_code
.
Notice, China is not included.  :-DD
Notice, Japan is not included. What's your point?
Title: Re: Red is Negative, Black is Positive in China?
Post by: SeanB on April 12, 2015, 07:44:26 am
At least one Chinese manufacturer uses wiring of green, red and yellow. Green is common, red is live and yellow is neutral. As it in any case came with a Australian standard plug attached, I simply opened it, put a proper cable along with a proper cable gland ( as opposed to the original of a hole drilled through the metal with the cable through it with a knot inside) to comply with local colour specifications, and with a South African/Indian standard plugtop as well. Ground went to a proper nut, nylock bolt and washer with a lug as well, not the original bare wire wrapped loosely around a random screw thread inside.

I did reuse the plug though, as Stuart had some Australian Yamaha gensets and was looking for a cheap source of the plugs, and I had also gotten some HP power leads with the Australian pattern as well so put them all together for him.
Title: Re: Red is Negative, Black is Positive in China?
Post by: coppice on April 12, 2015, 07:53:53 am
At least one Chinese manufacturer uses wiring of green, red and yellow. Green is common, red is live and yellow is neutral. As it in any case came with a Australian standard plug attached, I simply opened it, put a proper cable along with a proper cable gland ( as opposed to the original of a hole drilled through the metal with the cable through it with a knot inside) to comply with local colour specifications, and with a South African/Indian standard plugtop as well. Ground went to a proper nut, nylock bolt and washer with a lug as well, not the original bare wire wrapped loosely around a random screw thread inside.

I did reuse the plug though, as Stuart had some Australian Yamaha gensets and was looking for a cheap source of the plugs, and I had also gotten some HP power leads with the Australian pattern as well so put them all together for him.
\
The Australian standard plug and the Chinese standard plug are identical.
Title: Re: Red is Negative, Black is Positive in China?
Post by: videobruce on April 12, 2015, 07:55:08 am
Quote
Notice, Japan is not included. What's your point?
.
The "point" is, China, not Japan is in the threads subject.
Title: Re: Red is Negative, Black is Positive in China?
Post by: Zero999 on April 12, 2015, 02:01:33 pm
In the EU, the colour code for both AC and DC wiring is similar and the colour red is not part of this standard.

AC
L1 = Brown
L2 = Black
L3 = Gray
Neutral = Blue

DC
Blue is always the conductor which is at earth potential or is the centre tap on bipolar systems, so if it's negative earth it's -, if it's positive earth it's + and if it's bipolar, it's 0V.

Brown = + on negative earthed, unearthed or bipolar power supply
Grey = - on positive earthed, unearthed or bipolar power supply.

So if it's a battery powered installation and it's negative earthed you have:

- = Blue
+ = Brown

But if it's positive earthed you have:

+ = Blue
- = Gray

I suppose it's easier to say:

Gray = -V
Blue = 0V
Brown = +V

That's less confusing.

Green & yellow is always protective earth, irrespective of whether it's and AC or DC system.

The colours red and black, for DC systems have no official meaning, as far as the European wiring code is concerned.
Title: Re: Red is Negative, Black is Positive in China?
Post by: Rick Law on April 12, 2015, 04:58:29 pm
I think this whole wiring scheme is a Darwinist conspiracy...

They want to use it to clean up the industry of careless people.  One moment of carelessness and zap, you are fried.

Now I feel I am being personally attacked...
Title: Re: Red is Negative, Black is Positive in China?
Post by: SoundTech-LG on April 15, 2015, 01:53:09 pm
Where I work someone in the past, a firmware engineer I have been told, decided to use the Resistor Color Code, or Transformer Wire code in his wiring scheme to power our 4 volt battery device off a 3 volt to 5 volt level shifter. So Black, Brown, Red, Orange,Yellow. All good so far. Well then...  Black is + 4 Volts, and Yellow at the other end of the connector is Ground!  :-DD :palm:

It takes some getting used to...
Title: Re: Red is Negative, Black is Positive in China?
Post by: electr_peter on April 15, 2015, 04:28:51 pm
I had few scenarios where cable with identical pin-outs and connectors on both ends had different cable ordering on each end. 12V to 1V expecting circuitry or reverse polarity with "factory connector" :-//. Luckily, I always check cables so I spotted it before powering it up.