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Power Cable W/ a structural guide wire inside the jacketing???

Zac Penn

Plastic
Joined
Oct 4, 2019
Location
Jacksonville
EDIT: Sorry if this is SUPER off topic for this section of the website.

I am trying to save myself a couple steps in my Christmas Lighting Display, and was wondering if this type of cable...
- Already exists
- Is an economical option

Longest span will be around 300' from turnbuckle to turnbuckle (most will be between 120' to 250' long) and the weight of the power cord and christmas lights combined would be around 15-20 lbs every 100' of length. I am just guessing here, but I can weight last years display and see what that number actually is.

I am going to be connecting Micro LED christmas lights between many of the homes and trees in my Cul-De-Sac and my miniature attempt last year used an 1/8" wire rope as a guide wire to support all of the weight, and then i zip tied an old extension cord to the guide wire, and then made my electrical splices every 15' along the extension cord so i could drop down a vertical string of christmas lights at each splice.

This year, I have been advised that it is MUCHHHHHH quicker to use 14/2 Lamp Cord and use those Vampire Clips to splice into the lamp cord. I will also use a Female Socket at each of those Vampire Clips, so that when it is time to tear everything down, I do not have to keep the vertical strings of lights attached to the main power cord that spans between houses/trees.

That is going to save me the time of carefully cutting away the extension cord jackets, and carefully opening up the Hot and Neutral wire to make a splice that way, and make it way easy to store the display for 90% of the year, but now i want to try and save some extra time and have my power cable actually have a structural wire rope inside the jacketing, so that i can use that as a structural guide wire and power cord in one package.

This idea is going to work great if this mythical kind of cable actually exists AND is about the same cost as buying the cable and wire rope separately.

Thanks for any help!!!
 

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I doubt the exact combo exists but why not just fasten a 1/8" cable to the 14/2 lamp cord by taping with bands of electrical tape and allowing slack loops in the lamp cord at intervals to allow for the vampire clips?

AFAIK the only electrical cables with a pull member inside are heavy duty cables with a Kevlar cord inside the jacket as a strength member.
 
Lots of telco cabling has a steel 'messenger wire', where the actual cable unzips (like speaker wire) from the messenger wire - you generally don't want to be opening the cable jacket outside up on a pole; you take the tension using the messenger wire and the rest of the cable goes into a splice box.

That probably wouldn't help you because you wouldn't have any slack to make joints with, and I don't think there's any mains-rated cable with a messenger wire.

I'm slightly concerned about the lean on that lamp pole. It won't be designed for the sideload applied. Is there a backing/guy wire on the other side of it?
 
Further things to think about, especially with longer lengths and safety concerns of going over other properties:
  • This absolutely should be on a GFCI. Those ends are hanging down to where they're touchable.
  • Make sure the connection from the droppers to the catenary (both power and mechanical) will safely break away if say a kid swings on one, or a truck gets caught.
  • Voltage drop at long lengths.
  • At long lengths, there might not be enough fault current to trip the breaker in the case of a short between live and neutral. This is not something that is usually considered in the US. For a 15A MCB, you want about 120A to guarantee an immediate magnetic trip (not waiting (tens of) seconds for the thermal trip to warm up, and therefore a total impedance of no more than about 1 ohm on 120V line. 14AWG is 2.5Ohm per 1000ft, double it for there-and-back, and you can only go 200ft, including the length of building wire back to the panel in the house.
  • You should ground the steel messenger wire/catenary. If it is left floating it's possible it could become live. If these lines come down, you don't want a bare (or even PVC-jacketed) wire to become live.
I'm not sure how it compares cost wise to what you're planning, but one option would be "Voluta" #6 aluminium triplex service drop cable, e.g this at $1-1.20/ft.

You get:
  • Screeds of capacity for volt drop and fault current, being equivalent to roughly #8 copper. You'd be able to go about 800ft on the same one-ohm fault current limit, and would have about a 4% volt drop by the end assuming 10A of load evenly distributed.
  • Two insulated conductors (I would use them for hot and neutral) and a bare conductor (I would ground it).
  • An ACSR (Aluminium-clad steel reinforced) bare neutral rated for 1190lbf.
  • Total weight ~115lb/1000ft.
  • Piercing taps in the appropriate size are unfortunately a bit hard to find. It won't be as bad as however your were splicing into the extension cord, but it might be worse than the lamp cord vampires (which are illegal in much of the world).
  • Aluminium corrosion/expansion issues aren't a major issue at the low currents being considered. Keep the joints dry but you'll only need to do things 'properly' at the start where it connects to whatever you're feeding it from.
You can get duplex that's a bit cheaper and a bit lighter, and just use hot/neutral, but I'd rather not have a bare actual neutral given the lengths and strains. If it snaps, all that neutral becomes live.
 
Lots of telco cabling has a steel 'messenger wire', where the actual cable unzips (like speaker wire) from the messenger wire - you generally don't want to be opening the cable jacket outside up on a pole; you take the tension using the messenger wire and the rest of the cable goes into a splice box.

That probably wouldn't help you because you wouldn't have any slack to make joints with, and I don't think there's any mains-rated cable with a messenger wire.

I'm slightly concerned about the lean on that lamp pole. It won't be designed for the sideload applied. Is there a backing/guy wire on the other side of it?
Thank you for taking the time to reply, and sorry I didn't get back to you sooner. I have been up to my eyeballs in fabrication work so I haven't been on social.
The lamp pole in fact does have a counter-acting guide wire on the other side, so the pole remains in a straight alignment.
 
Further things to think about, especially with longer lengths and safety concerns of going over other properties:
  • This absolutely should be on a GFCI. Those ends are hanging down to where they're touchable.
  • Make sure the connection from the droppers to the catenary (both power and mechanical) will safely break away if say a kid swings on one, or a truck gets caught.
  • Voltage drop at long lengths.
  • At long lengths, there might not be enough fault current to trip the breaker in the case of a short between live and neutral. This is not something that is usually considered in the US. For a 15A MCB, you want about 120A to guarantee an immediate magnetic trip (not waiting (tens of) seconds for the thermal trip to warm up, and therefore a total impedance of no more than about 1 ohm on 120V line. 14AWG is 2.5Ohm per 1000ft, double it for there-and-back, and you can only go 200ft, including the length of building wire back to the panel in the house.
  • You should ground the steel messenger wire/catenary. If it is left floating it's possible it could become live. If these lines come down, you don't want a bare (or even PVC-jacketed) wire to become live.
I'm not sure how it compares cost wise to what you're planning, but one option would be "Voluta" #6 aluminium triplex service drop cable, e.g this at $1-1.20/ft.

You get:
  • Screeds of capacity for volt drop and fault current, being equivalent to roughly #8 copper. You'd be able to go about 800ft on the same one-ohm fault current limit, and would have about a 4% volt drop by the end assuming 10A of load evenly distributed.
  • Two insulated conductors (I would use them for hot and neutral) and a bare conductor (I would ground it).
  • An ACSR (Aluminium-clad steel reinforced) bare neutral rated for 1190lbf.
  • Total weight ~115lb/1000ft.
  • Piercing taps in the appropriate size are unfortunately a bit hard to find. It won't be as bad as however your were splicing into the extension cord, but it might be worse than the lamp cord vampires (which are illegal in much of the world).
  • Aluminium corrosion/expansion issues aren't a major issue at the low currents being considered. Keep the joints dry but you'll only need to do things 'properly' at the start where it connects to whatever you're feeding it from.
You can get duplex that's a bit cheaper and a bit lighter, and just use hot/neutral, but I'd rather not have a bare actual neutral given the lengths and strains. If it snaps, all that neutral becomes live.
WOW!!!!!!!!! You really put some thought into this. Thank you very much for that.
I already have TWO GFCI circuits on my house (one in the downstairs soffit and one upstairs) but I might run a 3rd circuit after reading your comments on resistance and the speed of the magnetic trip.
I ended up using 1/8" low-stretch polyester braided rope for the structural support on these runs, with a 350 lbs break strength. I figured that would be plenty for the weight of the displays, but not so much that it would completely destroy my soffit/light pole/semi-truck cowling/etc... if it got caught on something.

I also had two large spools of 12 awg stranded aluminum (i think it is aluminum but the jacketing doesn't have any writing on it) that I got for free in a large auction lot years ago. I unspooled the wires side by side and then twisted them together with my screw gun. I then zip tied them to the braided rope and installed the female vampire clips where needed.
I haven't actually hung them up in the air yet, but hopefully over the Thanksgiving holiday that will get done.

My longest run is 250 feet and with everything being LED, I wouldn't guess more than 3-4,000 mini-lights on each of those runs. I THINK the conversion is something like 69 Watts for every 1,000 mini-lights, so a Google calculator came back with around 2-2.5 Amps on that run.

I am sure the vampire clips will allow water to get into the wires and cause corrosion issues over the years, but if this "basically free" option works for a couple years then I would call it a win. It was TIME CONSUMING as all hell, doing it this way but it was free ;) I have used all of that wire now so I think I will just buy SPT-1 or SPT-2 lamp cord if I decide to make any new runs.

One safety benefit to using the female outlets at every vertical drop is that each of the connected light strands will have the factory installed, FUSED male connector that will blow and kill the power to each vertical drop if some idiot ends up running over the lights with a lawnmower or something like that. hahaha
 








 
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