Using clothesline steel core wire rope for AC and DC

acdcsafetysolar energywiring

As I am currently in a war zone, I don't have many options for cabling.

I found this clothesline (steel core plastic wire rope) that appears to be one mm of diameter (steel core diameter.) 13 meters of it measured 7 ohms resistance.
Edit: It is 3.8 Ω and not 7. The first multimeter test lead probes had 2-4 resistance when shorted. A slightly better multimeter had 0.5 Ω when shorted. Both multimeters gave 3.8 after subtracting multimeters own resistances and scratching the wire ends.

enter image description here

  1. Can it carry AC 120 or 240 volts, and if so, for what distance?
  2. How many of it (doubling it) can carry DC 18V and 15 A from a solar panel arrays 10 to 15 meters away from the inverter (charge controller)? (20 W panels with open circuit voltage of 21 V).

This is just temporary solution and I hope only for few days or weeks. Air strikes blew up some transformers and high voltage lines and our concrete homes are not designed to be habitable without AC power.

Its now connected to a c32 breaker (the smallest I could find) and a breaker mounting brackets cut from a laptop battery cover. The wire is inserted in plastic bottle caps as wire wall clips and a tow heads plug is inserted to the other end (to be upgraded to three heads) because now polarity is important I think.
enter image description here
enter image description here

I will connect it to a manual changeover switch when adding the solar oart after finishing the battery but that is another longer story (Lithium battery without BMS) but I may be able to reuse old laptop batteries BMS (I have more than 20 batteries): enter image description here

The solar system is only for a medium 100 W Samsung fridge and the mains are for the fridge plus two ceiling fan, one swamp cooler and three LED lights.

Best Answer

Steel, having just around 10 times higher resistivity than copper means it will take ten times the conductor area to match copper. If you measured 13 meter of it to 3.8 Ω, the cross sectional area would be 2 mm^2, assuming 5.95*10^-7 Ωm of resistivity for "high alloy steel" (this varies greatly unfortunately so assume +100% -50% uncertainty for all values given).

To answer your questions:

  1. How long = Time: probably many years. How long = Distance: Most devices will run happily with 10 % voltage drop. Anything universal input (100-240 V) could handle significant voltage drop due to the cable at which point it's the thermal capability of the cable which sets the limit as you don't want it to melt.

    With 3.8 Ω for 13 meter, you have 0.29 Ω/m. At 1 A 230 V AC current, you can go 39.7 meter (round trip is double distance) before you have dropped 10 % of the voltage. If you halve the current, it's double the distance. Gut feeling + experience says it would get lukewarm at 2-3 A so I would not go much above it.

Could be lethal though, as the insulation is not mains voltage rated. I would be more afraid of anyone coming into contact with the end points and the cable termination than touching the outer shell of the clothesline and somehow get zapped by it as they tend to sit outside for decades without becoming brittle by the UV exposure.

As stated below by Martin McCormick, your best bet is to put the inverter as close to the panels as you can and run AC through the clothesline versus low voltage DC current through the clothesline.

  1. With just one conductor, carrying 15 A via 3.8 Ω means a 57 V drop, so not possible with 18 V at all. It would also melt. To make it work at 18 V, perhaps 20 % drop (3.6 V) could be tolerated. To get down to 3.6 V drop, you would need 57/3.6 = 16 in parallel.