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Join Date: Sep 2008
Posts: 6

ACSR-795MCM and ACSR-795mm2 Conductors

10/08/2008 12:35 AM

Dear Engineers,

Kindly please help us to know the type of conductor ACSR-795MCM in some items as follows:

1/. What are the differences between ACSR-795MCM & ACSR-795mm2 conductors?

2/. Why do we use the symbol "MCM" in this conductor?

3/. What does the word "MCM" stand for?

4/. What type of conductors is ACSR-795MCM equivalent to?

I hope your supports could help us to understand.

With best regards

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Join Date: Oct 2008
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#1

Re: ACSR-795MCM & ACSR-795mm2 conductors!!!

10/08/2008 8:55 AM

To understand the differences in 795 MCM and 750 mm2, you must understand the MCM and mm2 are both measures of the conductors cross-sectional area … i.e., if you were to cut a piece off the conductor with a very sharp tool, how much cross sectional area you would be looking at.

mm2 – is just what it looks like square millimeters, or 1/1,000,000 of a square meter. So this measure is referring to a area one millimeter by one millimeter squared.

So for:

  • A solid bar 20 mm x 20 mm the area would be 20 * 20 or 400 mm2.
  • For a round bar 20 mm in diameter the area would be (πr2) π * 102, or about 314 mm2.

MCM – is thousand circular mills, and is an old designation. A mill is 1/1000 of an inch, and a circular mill is the area of a circle of that size.

To avoid the metric "M" "k" confusion issue, the designation kcmil is now preferred for thousand circular mills ("kcmil" = "MCM").

So … both mm2 and MCM are measuremt units of area, and 1 mm2 = 1.97 MCM (or approximately 2 MCM).

1. What are the differences between ACSR-795MCM & ACSR-795mm2 conductors?

795 MCM will have almost twice the cross sectional area of 795 mm2

2. Why do we use the symbol "MCM" in this conductor?

MCM is not used for current day conductor designations, kcmil is the preferred designation for this conductor, where 1 MCM = 1 kcmil.

3. What does the word "MCM" stand for?

See above … "thousand circular mills"

4. What type of conductors is ACSR-795MCM equivalent to?

In raw cross sectional area, 795 kcmil conductor would be equivalent to 380 mm2. However, as you are asking about ACSR conductors, there is more to the story on equivalency … these conductors will be build of "X" strands of aluminum conductor and "Y" strands of steel for strength, indicated as "X/Y". Common 795 kcmil conductor constructions include the following stranding: 36/1, 24/7, 45/7, 54/7, and 30/19. Each of these constructions have slightly different resistance and reactances, but significantly different mechanical strengths and costs.

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#2
In reply to #1

Re: ACSR-795MCM & ACSR-795mm2 conductors!!!

10/08/2008 11:41 PM

Thanks you very much for your helpful information.

1/. If the word "mills" in "thousand circular mills" phrase is "millimetre" meaning or something esle?

2/. Does the unit "kcmil" stand for? Could you please more obviously interpret?

Thanks again

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