Cross over AWG to expanded metal

[kurtis500]

Hello everyone, Im new here so go easy....

Is there a way to determine the equal mass or conductive material for expanded metal when AWG is referenced? We are embedding expanded metal as electrodes in a low temperature heating system (350F and lower) and are reviewing the UL standards. When AWG is referenced I am having a hard time crossing over the amount of material in expanded form to match that in wire form. Im sure this is a math calc, and as much as I love math I was never gifted at a high level. :weeping: For reference I posted a link below to an example of expanded metal. A strip approximately .5" wide of this material would equal ?? on the AWG scale
http://www.nilesexpandedmetals.com/nem/pdf/Aeromesh TPS CU195F.pdf

 

[mivey]

Hello everyone, Im new here so go easy....

Is there a way to determine the equal mass or conductive material for expanded metal when AWG is referenced? We are embedding expanded metal as electrodes in a low temperature heating system (350F and lower) and are reviewing the UL standards. When AWG is referenced I am having a hard time crossing over the amount of material in expanded form to match that in wire form. Im sure this is a math calc, and as much as I love math I was never gifted at a high level. :weeping: For reference I posted a link below to an example of expanded metal. A strip approximately .5" wide of this material would equal ?? on the AWG scale
http://www.nilesexpandedmetals.com/nem/pdf/Aeromesh TPS CU195F.pdf

You could use the circular mils to compare the material area. Many online calculators are available to make the conversion.

Not sure just a mass or volume comparison will give what you need. It would seem to me that you would need to consider the impedance comparison instead as they will not be the same given the difference in shapes.

 

[Carultch]

Hello everyone, Im new here so go easy....

Is there a way to determine the equal mass or conductive material for expanded metal when AWG is referenced? We are embedding expanded metal as electrodes in a low temperature heating system (350F and lower) and are reviewing the UL standards. When AWG is referenced I am having a hard time crossing over the amount of material in expanded form to match that in wire form. Im sure this is a math calc, and as much as I love math I was never gifted at a high level. :weeping: For reference I posted a link below to an example of expanded metal. A strip approximately .5" wide of this material would equal ?? on the AWG scale
http://www.nilesexpandedmetals.com/nem/pdf/Aeromesh TPS CU195F.pdf

The Wikipedia article on American Wire Gauge has the equivalents in both kcmil and mm^2. mm^2 will probably be easiest to compare to x-sectional area of other shapes (like bar stock for busbars). Given inch dimensions multiplied together, multiply by 25.4^2 to get mm^2, and compare that to the mm^2 equivalent of the AWG size of interest.

In terms of ampacity, a lot of other physics comes in to play, other than just cross sectional area. Remember that this is a thermal problem.
In terms of voltage drop, it is close enough to assume that all x-sectional area units have the equivalent conductance, no matter what the shape.

 

[petersonra]

MAYBE A CALL TO THE MANUFACTURER?

 

[GoldDigger]

The Wikipedia article on American Wire Gauge has the equivalents in both kcmil and mm^2. mm^2 will probably be easiest to compare to x-sectional area of other shapes (like bar stock for busbars). Given inch dimensions multiplied together, multiply by 25.4^2 to get mm^2, and compare that to the mm^2 equivalent of the AWG size of interest.

In terms of ampacity, a lot of other physics comes in to play, other than just cross sectional area. Remember that this is a thermal problem.
In terms of voltage drop, it is close enough to assume that all x-sectional area units have the equivalent conductance, no matter what the shape.

To me the OP's post is (or should be) more of a question of effective surface area (with adjustment for sphere of influence) of a particular square footage of expanded metal as compared to the same value for a particular length of a particular gauge wire.

When talking about CEEs, the code specifies 20 feet of either 1/2"+ rebar or #4AWG+ bare copper. Those combinations of length and size are, IMO, chosen for their surface area in contact with the concrete, not just the resistance of the length of metal.

The adequacy of the OP's electrode will depend on the effective surface area of a linear foot of the mesh as well as its resistance per foot resulting from its cross section.

Although for the narrow width (.5") mentioned by the OP, the resistance per unit length probably will come into play too.
The idea that expanded metal of a particular weight per linear foot based on width should have about the same resistance as the same weight per foot iron wire seems to be the best way to approach that problem. The correction required by the zig-zag path through the mesh should not be more than say 30%.

 

[mivey]

The idea that expanded metal of a particular weight per linear foot based on width should have about the same resistance as the same weight per foot iron wire seems to be the best way to approach that problem.

It is a copper mesh that has, just for grins, the thickness of 41.1378 AWG wire.

 

[mivey]

A strip approximately .5" wide of this material would equal ?? on the AWG scale

22.38649022 AWG

 

[mivey]

22.38649022 AWG

Oops, I forgot the shape factor. The corrected answer is 21.24316841 AWG

 

[mivey]

Oops, I forgot the shape factor. The corrected answer is 21.24316841 AWG

One more time, I multiplied instead of dividing :dunce:. The corrected, corrected answer is:

25.66777683 AWG resistance equivalent

FWIW, I got a 67% zig-zag factor

 

[kurtis500]

Thank you everyone for the input. I am, and have been grinding away trying to trace the paths of your calculations.. Im getting there, but want to put in all the hard work before I ask a bunch of questions..

We are working with the manufacturer of the expanded metal and are trying to size the appropriate expanded metal electrodes to the application. We have various items that will use these as electrodes. The products are made of fiberglass and expanded metal has a long history of embedding well within laminates such as lightning strike protection and some others. Expanded metals allow for adhesion of the laminates through the expanded metal electrode and therefore a strong bond within the laminates being made. I attached a photo of heaters similar in design but not a direct competitor to what we are doing. We are able to expand the copper to any shape and size needed. The photos shows the heater with the layer of silver between the copper and carbon heating element.