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I want to make an electric/heating blanket that will work with heating electric cable.

I will use a computer AC adapter that output 19V 3.16A, and this dimmer to regulate the heat and a heating cable sewn in a 1.60x1.20m blanket.

I have some trouble to find out which type of heating cable will be better for my project.

Knowing that the cable could touch my skin, it should not be to hot: the ideal temperature of the cable should be around 40 (45°C/113°F start to burn the skin). I have seen that, at a constant voltage, the heat depends on the current which depends on the resistance of the cable and the length of the cable (I guess I will need between 8 or 9 meters of heating cable).

Since I need a cable that will generate a temperature of about 40°C for 8 meters of cable, which type of cable will be the best?

  1. Carbon fiber flex heater tape is too expensive.
  2. I have seen Kanthal and Nichrome wires, but they don't seem to be coated so they seem dangerous.
  3. This silved plated copper looks good (Polytetrafluoroethylene PTFE coated).
  4. Also this Carbon Fiber Heating Cable seems great because it's infared heat but I can't find one that will work on a 12V-24V tension.
  5. Do you have any other suggestions?

Since I’m living in Europe, I'll be very grateful if you could advise me on the type of material but also its precise specification (diameter in AWG or mm, Ohms/meter...) to be able to buy the equivalent here in Europe.

Thanks a lot for your help!

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  • \$\begingroup\$ Note the cable's resistance per unit length is what concerns you. Not the "rated" voltage that is specified. Ohm's law is your friend here - you can simply cut the wire to shorter pieces and connect them in parallel. \$\endgroup\$ – Dzarda Dec 10 '14 at 10:17
  • \$\begingroup\$ Thanks @Dzarda. I can never find the cable's resistance per unit length on the cable information. Also I have some troubles with Ohm's law. \$\endgroup\$ – MagTun Dec 10 '14 at 11:43
  • \$\begingroup\$ Make sure you understand the difference between heat and temperature; they're two different things. Your "heating cable" is simply a resistor that converts electrical energy into heat. However, the temperature that is reached depends on the relative rates at which heat is delivered by the cable and heat is lost to the environment. You may need to regulate the temperature by varying the heat input. \$\endgroup\$ – Dave Tweed Dec 10 '14 at 13:29
  • \$\begingroup\$ It was difficult to find cable with the correct resistance per unit of length so here's the one I found: Isotan Konstantan Enamel Insulated Resistance Heating Wire 0.70 mm, AWG 21. \$\endgroup\$ – MagTun Dec 11 '14 at 9:07
  • \$\begingroup\$ For safety, because heating blankets can be (for instance) buried under a pillow and thus thermally insulated, most electric blankets have a multiplicity of thermal sensors that shut down sections at elevated temperature. Blanket temperature should NOT be expected to be uniform. It takes more than current limiting and resistance wire to make a safe, useful electric blanket. \$\endgroup\$ – Whit3rd Jan 11 '17 at 10:49

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