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I think that there could have been a thread somewhere about this but I couldn't find it. Is it possible to use that black low-voltage to make extension cords? It's much thicker than most of my blow mold cords, it's made for outdoors, I don't see why it wouldn't work. Has anyone tried using this wire?
The problem with the Malibu cable is that it is only rated for 30 volts not the 300 that normal SPT cable is rated for. The problem is that it does not have the same dielectric strength that 300 volt insulation has.
What I prefer is SPTW which is weather proof and holds up much better than standard SPT cable, the problem is you typically have to special order it. This is also what Malibu used to sell but they have now switched to an insulation with lower dielectric strength.
Tony
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
____________________ No really... Just one more light and I'll be finished....
Disclaimer: If you take any of what I say as non-constructive, it's not how I intended it.
It's rated to 150 volts, the jacket also looks much thicker and is more flexible than normal SPT2 or lamp cord. It's also rated for outdoor use.
This will be used for a wiring harness going up my 48' tower in my back yard. I'm going to hang four 6 foot panels of lights, with red, green, and clear on each panel.
I'm not going to tell you that you can use it, the cable is UL listed as a low voltage cable, which means 30 volts or less of applied potential. If you look at normal line voltage power wiring you'l see that the insulation is either 300 or 600 volt rated. It's your call but if it were me I wouldn't use it.
Tony
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
Remember 110 volts is the RMS value (Root Mean Square), that means the average of the entire voltage. The actual Peak voltage is 1.414 of the RMS value or 155.54 Volts at the highest peak of 1/2 of either cycle. Its 2.828 for both cycles (positive and negative cycles). So you really have 311.08 volts peak to peak.
Now your Volt meter only shows the RMS value, but if you have a scope you will see the 311.08 voltage.
Now do you want to chance a low voltage insulated rated cable to prevent the 300 volt actual power of 110VAC from shocking you or someone else?
There is a very good reason why cables are rated, its for safety.
Your choice, your life.
Last edited on Monday April 7th, 2008 10:32 pm by Dennis Cherry
You are correct, I avoided that explanation to try and avoid confusing people but you are absolutely right. Even though the wire itself is the same gauge as SPT1 or 2 the insulation is dramatically different and has different dielectric or insulating properties.
Tony
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
Dennis Cherry wrote: Now your Volt meter only shows the RMS value, but if you have a scope you will see the 311.08 voltage.
Now do you want to chance a low voltage insulated rated cable to prevent the 300 volt actual power of 110VAC from shocking you or someone else?
To be fair, it is not possible to have both the positive and negative peaks on the line at the same time, so the highest voltage the cable will see is 1/2 of the Peak to Peak voltage. First you have the positive peak, then that goes back to zero, then you have the negative peak, then back to zero, etc.
Still, it's not good to use low voltage cable with line voltage!
Later. . . . . . . Brad
____________________ NEC 408.41 - ONLY exception is parallel conductors!
Of course, the landscape wire was still only 150V rated, so you still are a little past the rating with zero safety margin, and I would expect that the wire voltage rating is before any physical damage is present. Especially on this low voltage cable, I'd think that comparing thickness is kind of like thinking that all LED's are the same color. It ignores the minor changes in chemistry that make such big differences in the end result.
Side thought.. I don't expect it to be very many, but I wonder how many of those who never can locate and clean up their gfci trips are using landscape wiring?
You are correct, I avoided that explanation to try and avoid confusing people but you are absolutely right. Even though the wire itself is the same gauge as SPT1 or 2 the insulation is dramatically different and has different dielectric or insulating properties.
Tony
You are correct Tony. I forgot to mention that. UL tests insulation for break down voltage, if your nominal voltage is 110VAC or 155.54 Peak then UL wants at least 100% safefy protection over the peak value or maximum. So the minimum insulation breakdown for insulation on wire for 110VAC has to be 300V.
It's not just the low voltage grade cable but wiring in general, small nicks and cuts in the outer surface degrade the insulating characteristics of the wire and can cause leakage of water in and then current out.
Thats why I take my cords and saturate them with the garden hose and then test them with a megger every year to see if there are any potential issues with insulation breakdown. I also test my light strings and other electrical display elements. By doing this I minimize my potential for GFCI trips.
Tony
____________________ Do not meddle in the affairs of dragons, for you are crunchy and taste good with ketchup.
Tony Furst wrote: What I prefer is SPTW which is weather proof and holds up much better than standard SPT cable, the problem is you typically have to special order it. This is also what Malibu used to sell but they have now switched to an insulation with lower dielectric strength.
I've never heard of that before. Is it resistant to UV light like outdoor cords? (I'm thinking yes?) How much more expensive is it?
I think just for the sake of research I will take one of my 500 foot rolls of 150v rated 10 gauge carol cable and put it up on the HiPot tester at work and measure the leakage.
I can compare it to the SPT1 18 gauge we use which is rated for 300v just to see what kind of difference there is...
If nothing else... it will be perfect for about 30 of the MR16 LEDs from Wirekats group buy!
