Use of Expanded Metal as power supply

[kurtis500]

Are there any thoughts about expanded copper being used as a power supply in electrical appliances that use 110VAC per NEC? Expanded copper is a solid sheet which is run through an expander so the integrity of the material is good and the strands can be calculated for resistance based on size (and some other factors). Any thoughts on this? This devices would be similar to a circuit board except expanded copper instead of the sheet. Naturally a change in ressitance over the solid copper sheet would be needed.

Thanks

 

[roger]

If you are talking about circuitry inside a manufactured appliance it would not be an NEC issue, it would most likely need to be listed under a NRTL.

Roger

 

[kurtis500]

If you are talking about circuitry inside a manufactured appliance it would not be an NEC issue, it would most likely need to be listed under a NRTL.

Roger

I looked as much as possible but cant find anything. Seems like everything I have found is product specific. PCB circuitry calculates by trace width length etc. Using the copper strands dimensions Ive calcualted the amountof copper by mm^2. The material is an aerospace lightning strike mesh and we regularly test batches with certified equipment. My guess is the copper source and purity must be traced and our standardized testing would validate the copper. I just cant find anything about expanded foil as a conductor. Its used in battery and lightning strike for current carrying. Maybe no info is there because there really hasnt been a need to use expanded metal over wire or bars? Any thoughts

and thanks again.

 

[gadfly56]

I looked as much as possible but cant find anything. Seems like everything I have found is product specific. PCB circuitry calculates by trace width length etc. Using the copper strands dimensions Ive calcualted the amountof copper by mm^2. The material is an aerospace lightning strike mesh and we regularly test batches with certified equipment. My guess is the copper source and purity must be traced and our standardized testing would validate the copper. I just cant find anything about expanded foil as a conductor. Its used in battery and lightning strike for current carrying. Maybe no info is there because there really hasnt been a need to use expanded metal over wire or bars? Any thoughts

and thanks again.

Out of curiosity, what would you perceive to be the advantages of the expanded copper?

 

[kurtis500]

For use as an electrode in a composite based heater. The open area of the expanded metal allows the resins to cure through the metal locking it in to the composite. Placing a solid copper bar/wire in a fiberglass/carbon part creates a de-laminating line. Expanded metals have a long history in composite use, so using the expanded metal to conduct electrical cureent within the composite is the goal. Expanded metal allows turning on a surface where a solid copper bar or tape must overlap itself. The diamond opening collapse on the inner radius while it widens on the outer without altering the copper strands. I atteched a pic of a heater. The black lines are the heating elements, the copper carries the power.

 

[gadfly56]

For use as an electrode in a composite based heater. The open area of the expanded metal allows the resins to cure through the metal locking it in to the composite. Placing a solid copper bar/wire in a fiberglass/carbon part creates a de-laminating line. Expanded metals have a long history in composite use, so using the expanded metal to conduct electrical cureent within the composite is the goal. Expanded metal allows turning on a surface where a solid copper bar or tape must overlap itself. The diamond opening collapse on the inner radius while it widens on the outer without altering the copper strands. I atteched a pic of a heater. The black lines are the heating elements, the copper carries the power.
View attachment 19051

Ahhh, now I understand. Clever solution. I'm with Roger on this, not an NEC covered issue. If it's part of a larger assembly, it might fall under the UL listing for the equipment. Can't help you there.