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Is it a good idea to replace wires that get bent a lot (e.g., around a hinge) with conductive threads? It's a 5V device using up to 1A.

Thanks

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  • \$\begingroup\$ Take the front off your dishwasher and look how they do it... Historically they were terrible for breaking wires in the hinge, but more modern ones seem to have got better, mainly by having clever sliding/folding guides to keep the bend radius large. \$\endgroup\$ – user1844 Jun 29 '15 at 19:33
  • \$\begingroup\$ I've used some 'super-flexible wire' which was really a spiral of conductor wrapped around a glass-fiber core. It looked like a 22-AWG wire from a distance, but it was effectively only about a 30-AWG at best since the bulk of the 'wire' was actually glass-fiber. \$\endgroup\$ – brhans Jun 29 '15 at 20:10
  • \$\begingroup\$ Look for wire sold for test leads. It has many more, finer, strands than normal, and more flexible insulation. \$\endgroup\$ – Brian Drummond Jun 30 '15 at 11:28
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Conductive thread is simply thread with wire woven through it, so it won't necessarily be any more robust.

The critical thing for reducing fatigue in wires that are flexed a lot is to maximize the radius of curvature. Instead of bending it directly around the hinge, use a generous loop of wire, so that the maximum curvature is very gentle. You may also consider looking for cable that is specifically rated to withstand a lot of flexing.

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  • \$\begingroup\$ Aren't some conductive threads simply nylon thread with silver coating though? Those should be more robust, right? \$\endgroup\$ – Kar Jun 29 '15 at 18:54
  • \$\begingroup\$ The trade off being higher resistance and low current capacity \$\endgroup\$ – Passerby Jun 29 '15 at 18:59
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I wouldn't necessarily use conductive thread for this, because the resistance is actually pretty high -- 10's of ohms per foot. Ohms law says that if you sent 1 amp through 1 ohm (an inch or so of conductive thread) the voltage drop across the thread will be 1 volt. The power through the thread will be 1 Watt. This may be fine for you, but you will have to pay attention to the voltage your load actually sees.

I recommend considering Flat Flexible Cables -- but you'd need to pay attention to how many cycles of motion will cause failure

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  • \$\begingroup\$ Of course, you can use a bunch of threads in parallel, but it probably still isn't the way to go -- or you'd see products that use this for this purpose. \$\endgroup\$ – Scott Seidman Jun 29 '15 at 19:14
  • \$\begingroup\$ How about fabrics? Conduct fabrics have lower resistance, right? \$\endgroup\$ – Kar Jun 29 '15 at 19:27
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Microflex Wire and Cable, among others, makes extra flexible wire for these applications.

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