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#137701 - 07/25/03 09:54 AM AWG to MWG?
C-H Offline


Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
I looked at a table with AWG to mm&#178 conversions and it occured to me the sizes are very close to each other. If you fit the AWG to a metric size: E.g. #18 to 0.80 mm&#178, #17 to 1.00 mm&#178 and #16 to 1.25 mm&#178 you end up with something that is only five percent or less smaller than the true value.

As I know that these 1.25 mm&#178, 2.00 mm&#178 etc. sizes are used in some countries, I got the idea to devise a new wire gauge. Let's call it MWG, Metric/Metricated(???)/Metrified(???) Wire Gauge.

The scale then goes like this:

30______0.0500 mm&#178
29______0.0630 mm&#178
28______0.0800 mm&#178
27______0.100 mm&#178
26______0.125 mm&#178
25______0.160 mm&#178
24______0.200 mm&#178
23______0.250 mm&#178
22______0.315 mm&#178
21______0.400 mm&#178
20______0.500 mm&#178
19______0.630 mm&#178
18______0.800 mm&#178
17______1.00 mm&#178
16______1.25 mm&#178
15______1.60 mm&#178
14______2.00 mm&#178
13______2.50 mm&#178
12______3.15 mm&#178
11______4.00 mm&#178
10______5.00 mm&#178
9_______6.30 mm&#178
8_______8.00 mm&#178
7_______10.0 mm&#178
6_______12.5 mm&#178
5_______16.0 mm&#178
4_______20.0 mm&#178
3_______25.0 mm&#178
2_______31.5 mm&#178
1_______40 mm&#178
0_______50 mm&#178
00______63 mm&#178
000_____80 mm&#178
0000____100 mm&#178

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#137702 - 07/28/03 04:01 AM Re: AWG to MWG?
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
I see where you're coming from on this, but as any new system would run alongside existing standards rather than replacing it (at least in the short term), I can't help thinking that it would result in some confusion.

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#137703 - 07/31/03 10:52 AM Re: AWG to MWG?
C-H Offline


Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Just for comparison the actual values are like this:

AWG___mm&#178

4/0__107
3/0__85.0
2/0__67.4
1/0__53.5
1____42.4
2____33.6
3____27.0
4____21.2
5____16.8
6____13.3
7____10.6
8____8.35
9____6.62
10___5.27
11___4.15
12___3.31
13___2.63
12___2.08
15___1.65
16___1.31
17___1.04
18___0.823
19___0.653
20___0.519
21___0.412
22___0.325
23___0.259
24___0.205
25___0.163
26___0.128
27___0.102
28___0.0804
29___0.0646
30___0.0503

As you can see, the difference is significant only for sizes 0 and larger.

At the same time, anyone familiar with metric sizes will object. Quite correctly: The last few sizes in the first message don't exist. For some reason the sizes leave logic after 25mm&#178. Instead of 40 like you would expect, they have choosen 35. And this then goes on with illogical sizes like 95mm&#178. The whole thing should be reworked.

Here's the MCM to actual metric to my suggested 'rough' conversion. Why are there so many MCM sizes? You can't possibly stock them all.

2000___1013____1000mm&#178
1750___887_____Remove size
1600___809_____800mm&#178
1500___760_____Remove size
1250___633_____630mm&#178
1000___507_____500mm&#178
800____405_____400mm&#178
750____380_____Remove size
700____355_____Remove size
600____304_____315 mm&#178
500____253_____250 mm&#178
450____228_____Remove size
400____203_____200 mm&#178
350____177_____Remove size
300____152_____160 mm&#178
250____127_____125 mm&#178

Look at the numbers and you'll see that the conversion is rather simple...

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#137704 - 07/31/03 11:18 AM Re: AWG to MWG?
JohnS Offline
Member

Registered: 07/31/03
Posts: 36
Loc: Cleveland, Ohio USA
I see no reason to introduce a new wiring gauge standard just because the Americans have to be different from everyone else. If the present square millimetre standard is the most universal, then it is up to countries like the US to adopt it.

However, if the Americans want to be different and keep their wire standard, they can at least establish new names for their wires (based on the information in your chart) on the square millimetre designation.

The advantage to this for both the US and the world would be the ease at comparing sizes. Without a chart handy, one only can guess if a 2.50 mm² can be used in place of a #14 AWG. If the Americans renamed #14 AWG as 2.00 mm², then it is obvious that 2.50 mm² can be used in applicatons where 2.00 mm² is specified, but not the reverse.

Most of the Asian countries do not use the same sizes as the Europeans. The 1.25 mm² and 2.00 mm² you referance are two of the sizes used in Asia. The Asian sizes may have been based on the AWG standard, but long ago adopted to the square millimetre naming designation. In other words, they may be using the AWG sizes with a square millimetre designation. The two "standards" are easily comparable as a result.

All the Americans need do is investigate if the Asian sizes can safely be used in the US and if they can, it would be so easy just to adopt new names without changing anything or changing it ever so slightly.

The only reason the Americans won't do it is because of attitude. We are better then everyone else. They must change to our ways, not us to the theirs. The only reason for the resistance to adopting SI in the US is because the Americans are afraid the world would interpret the change as the US having been wrong for 200 years and gods are never wrong. So, everything is done the hard way. The US is only hurting itself.

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#137705 - 07/31/03 11:40 AM Re: AWG to MWG?
C-H Offline


Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Welcome to ECN, John!

Harsh words there.

One shouldn't harmonise for the sake of harmonisation. However, I know that the Americans wire manufacturers are trying to figure out a way of harmonising the mm2 with the MCM and AWG system since they want to sell abroad. The sheer number of AWG to mm2 tables on the net indicate that people often have to convert. Just not for electrical stuff, but electronics, audio gear and various strange things.

Just like you point out, the Asian countries (including Japan and Korea) are using metric versions of the AWG. I've looked at the Japanese sizes, and either I've got something wrong they have been converting a bit at random since some sizes are rather strange, like 5.5, 14 and 22mm².

[This message has been edited by C-H (edited 07-31-2003).]

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#137706 - 07/31/03 01:31 PM Re: AWG to MWG?
C-H Offline


Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
An old ROP for the 1999 NEC (I think!) from SouthWire touching this subject
http://www.southwire.com/tech/pubs/pcu/97/pcu0897.htm

It isn't in the 2005 draft.

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#137707 - 07/31/03 04:09 PM Re: AWG to MWG?
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Quote:
One shouldn't harmonise for the sake of harmonisation

I agree entirely -- Which is why there is no need for America to change its wire sizes at all.

AWG has been the standard in the U.S. (and beyond) for decades, and introducing a new system would result in unnecessary confusion.

It seems to me that the ROW (Rest Of World) is frequently berating America for not falling into line with "established international standards," whether those standards are electrical or anything else.

I see the situation from the point of view that America already has its own standards which are perfectly satisfactory and understood right across the country. (And in many cases, the American standards have been in use much longer than the Johnny-come-lately ROW standards.)

If it ain't broke, don't fix it!

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#137708 - 07/31/03 09:32 PM Re: AWG to MWG?
JohnS Offline
Member

Registered: 07/31/03
Posts: 36
Loc: Cleveland, Ohio USA
The US doesn't have to change the physical suze of its wire, just give the wire a square millimetre name.

If the US was an isolated country or a net exporter like it was 30 years ago or more, then there would be no need to make any changes.

But, that is no longer the case. American differences cause grief to both sides, in the form of errors and economy.

With the US continuing to export its manufaturing and now engineering base, it becomes even more important to harmonise. It isn't harmonsing for the sake of harmonising, it is harmonising for the sake of safety and economy.

With huge deficits, the rise of the euro against the dollar and the demise of dollar hegemony, the US is either going to have bend some towards harmonising or suffer the consequences of being different when it can no longer afford to be so.

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#137709 - 08/01/03 07:48 AM Re: AWG to MWG?
C-H Offline


Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Well said John.

My point is that the American electricians wouldn't know that they had a new system. The difference is to small to need any adjustment in ampacity. Only the engineers and the cable manufacturers would know that an adjustment has taken place. And those who for one reason or another want to use the advantage of metric sizes. (Like being able to calculate voltage drop in a run on the back of an envelope, without a table)

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#137710 - 08/01/03 12:25 PM Re: AWG to MWG?
C-H Offline


Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Link to LG cables

You can look at the 600V cables. It looks like the Koreans and the Japanese follow the American colour code, use their own sizes and have European-inspired cable designations. You will find the ampacities for the cables too.

Anyway, the wire sizes in these tables are as follows: (* indicates that it coincides with my suggested sizes)

mm²

2.0*
3.5
5.5
8.0*
14
22
38
60
100*
150
200*
250*
325
400*
500*
600
800*



[This message has been edited by C-H (edited 08-01-2003).]

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