Author Topic: STRANDED WIRE > romex wire (Read 6041 times)

fukenfooser · « **on:** October 22, 2005, 02:55:04 PM »

You can think and say what you want BUT!

Stranded wire is THE WAY to better efficiency!

Not being an expert or anything, (Electrical Tech Grad, Looong ago, couple lifetimes maybe).

What I do know is that two cabins wired the same with equal solar systems, only difference being cabin 2 was wired using stranded and cabin 1 was wired using romex.

Cabin 1 needs to run gen A LOT, just about fulltime!

Cabin 2 runs off the 12 V DC Solar system full time only fires up gen to watch movie on larger TV.

Most times I just watch on my 5" LCD hooked up to the 12 V DC, Lucky me the Gear2Go 5" LCD also came with an inverter, use it to power the DVD Player.

Lucky me also to have met a girl with a cabin almost finished!!

Her brothers and her built it and was # 2, being done so cabin 1 was learning curve and cabin 2 is the better version, as far as power systems go that is! Owner of cabin 1 had heard "STRANDED WIRE" would be better and was sisters money so why not, ( My thoughts on that one)!

Each room and hall as lights @ 120 V AC switched on walls and also have 12 V DC lights switched from pull strings. Bummer I didn't met her sooner because no 12 V DC outlets in all rooms just a couple in the main Ground floor for fan by the propane furnace and one by the yet to be installed wood-stove for heat. Also was one for sterio but I quickly put a gauge on it from a boat dash board to have a easy state of charge reference. I have had to tap into the light sockets for my power cause I can run a lot off of 12 V DC.

Being just the boyfriend I'll have to setup my own battery bank and want to have a wind gen to charge it, so Big Brother will see what can be done and might understand that I do know what I'm doing and let me be. I might even build one for his power hungry cabin its more out in the open and would get better wind, GOOD place for my gen also!

I have plans for a solar water heater and will need to prove myself first, But with the easy to learn stuff I have gained from this board, I might be able to do it!

Thanks to all who have posted !

drdongle · « **Reply #1 on:** October 22, 2005, 01:33:51 PM »

I suspect that something else is responsable for the differance between the two systems other than wither the wire is stranded or solid. While I happen to perfer stranded for most applications as it's easer to work with, there is no efective differance between the two.

TomW · « **Reply #2 on:** October 22, 2005, 02:17:26 PM »

Lets not forget that solid wire can require retightening the connectors over time.

I suspect there is another cause here that you just don't know about because the wire difference was the most obvious..

Cheers.

TomW

Smithson · « **Reply #3 on:** October 23, 2005, 06:54:27 AM »

Years ago when I took a home study course from National Radio Institute the comment was made that stranded wire had less resistance than single strand wire. The reason was that current travels on the outside of wire so it was easier in stranded wire for the current to flow. I have never seen that information again and it may just be a part of the ever changing "theory" of electricity and dropped by the wayside now. Smithson

TomW · « **Reply #4 on:** October 23, 2005, 07:15:48 AM »

Smithson;

I believe "skin effect" as that is know as only comes into play at higher frequencies above 50 / 60 cycles.

Aircraft use hollow wire in some applications on the 400 hz. AC bus. Hollow to save weight but supposedly same current carrying ability as sold wire of same size. Its been a couple decades since I worked in avionics but that is my memory of it.

Cheers.

TomW

Zix · « **Reply #5 on:** October 23, 2005, 08:20:09 AM »

Unless you have a loose connection there is no differance between solid and stranded wire in this application.

Zix

fukenfooser · « **Reply #6 on:** October 23, 2005, 09:27:01 AM »

"travels on the outside of wire"

Thats what I couldn't remember from my Looong ago schooling in electricty!

I knew there was a reason for stranded being better, How many auto's

has anybody seen using solid wire??

Thats why the cabin is SO MUCH BETTER than the other cabin.

Cabin 1 used romex needs all 4 panels but still running gen more than half the day!

Cabin 2 used stranded and only has 2 1/2 of the panels hooked up and only runs gen

for using large OLDER than DIRT tv. Has the anti-glazing coil than needs major amps on start-up, I told her I could remove it but they still don't belive in my skills, or

rather my ease at trying anything.

So I remain convinced

STRANDED > Solid

thanks

ff

amiklic1 · « **Reply #7 on:** October 23, 2005, 09:27:24 AM »

I would not share your oppinion.

I got wind gen control box (regulator and the rectifir) about 10 meters ( ca. 33') from the battery bank. They're connected with 10 square mm cables. When I measure the voltage at the control box, and than at the battery side of the wire ( with battery disconnected, which means open circuit), I got allmost no difference ( 14.1 at box and 14.0 at bat side). From the batteries to the inside of the house, I got solid wire 2.5 sq. mm (usually used in 220 volts systems). Now, measuring point is about 3 meters far from the battery bank, and when I connect ends of the 10 sq mm wire wit those that goes inside, and than measure inside, I got about 1.2 volts voltage drop. How to explain that? I am an electrician, and everything is done just OK. The difference is obvious, so I'll suggest everyone to use stranded wire, not solid.

halfcrazy · « **Reply #8 on:** October 23, 2005, 10:38:34 AM »

the main reason stranded is used in autos is that it is way mer flexible if solid wire flexes to much it can fail stranded is much better for autos boats etc in a house romex is the stadard and not shure if there is a lot of readily available stranded cable that is ul listed for high voltage in the walls of the house?

pyrocasto · « **Reply #9 on:** October 23, 2005, 01:52:17 PM »

Convinced or not it's not really true. For our application we are using 60~ hertz and you shouldnt not see any noticible differences. The only difference for us is that it's easier to work with.

Have you ever tried to work with 8 gauge and larger solid wire? You've got to be a beast make small bends and such in it.

richhagen · « **Reply #10 on:** October 23, 2005, 03:35:03 PM »

I'm with Tom on this one. I would think that it has to be something else. The resistance of the cables is about identical so, the power loss in the cables should be the same. In one old (NEC I think) book I recall it recommended up-sizing stranded wire by one wire size as compared to solid, although that may have to do with fatigue or mechanical strenght. For extremely high current, the surface area might come into play. I know that for high voltage, high current copper buss bars, they are somtimes plated with a silver/copper coating to reduce the overall resistance. I havn't found any documentation that indicates that the surface area would be a signeficant factor in the voltage and current ranges that we are likely to use for a low voltage solar system. The bus bars I mentioned above have a much higher ratio of cross sectional area to surface than cables that we would be using as well. If I have it available, I use solid for anything that isn't going to flex or move, and for which I can get a fish to pull it through the tube. Rich Hagen

Zix · « **Reply #11 on:** October 23, 2005, 03:44:09 PM »

TomW,

You are correct,the skin effect only applies to frequencies hgher than 60 cycles.

Stranded wire is used when flexability and vibration are factors but solar panels could care less about what kind of wire they are feeding.The only thing I can think of is maybe the solid wire is NOT copper.I worked in a electronics lab for years and ran test to comfirm this.

Zix------------------------------

I believe "skin effect" as that is know as only comes into play at higher frequencies above 50 / 60 cycles.

Aircraft use hollow wire in some applications on the 400 hz. AC bus. Hollow to save weight but supposedly same current carrying ability as sold wire of same size. Its been a couple decades since I worked in avionics but that is my memory of it.

Cheers.

TomW

mkseps · « **Reply #12 on:** October 23, 2005, 05:52:04 PM »

There is no difference between stranded and solid copper wiring. As was said by others, stranded wire is used in applications where vibrations or flexing is encountered. To properly determine a given wire size, the circular mills measurement must be made. With solid wire, the circular mils can be calculated from a micrometer measurement of the wire diameter minus any coatings. In the case of stranded wire, the diameter of one strand is measured with a micrometer and this answer is multiplied by the number of strands. You cannot merely measure the diameter of a bundle of stranded wires. As for the skin effect on the current carrying capability of copper wires, don't worry about it. That only comes into play in the RF spectrom, ie., 500,000 cycles and above. Applications below these frequencies is generally for reasons of weight reduction.

Gene

hiker · « **Reply #13 on:** October 23, 2005, 11:30:49 PM »

i know for speaker wiring--you always use stranded wire --the bigger the better..

if you don"t use stranded wire the highs don:t come out as well..

don"t have the slightest idea what this has to do with house wiring--thought i might toss it in anyway..................

ghurd · « **Reply #14 on:** October 23, 2005, 11:41:46 PM »

Could it be the highs are high frequency,

So the skin effect could come into play?

Thats what, 10~25khz?

Seems to prove the point with a practical example.

G-

ghurd · « **Reply #15 on:** October 23, 2005, 11:45:53 PM »

There has to be something more that is different.

Inverters? Batteries? Wire length?

Cabin #1 has a very real problem somewhere.

For sure.

G-

terry5732 · « **Reply #16 on:** October 24, 2005, 01:42:53 AM »

Did anybody else notice way up there he said the solid wire was 1/4 the size of the stranded?

halfcrazy · « **Reply #17 on:** October 24, 2005, 04:32:21 AM »

yes the stranded was 10 mm and the solid was 2.5 mm? not really folowing the hole metric thing i didnt pick up on that that would make a huge difference in voltage drop right there. we need apples to apples if you are going to claim real world test data.

fukenfooser · « **Reply #18 on:** October 24, 2005, 06:32:53 AM »

No

I never said what, about any wire Ga.

All I said was the difference is major.

I wasn't involved in the wiring of either cabin.

I just know what the owners of tem have told me and what I see when up there

and it's more of what I hear.

Nothing at cabin 2.

But sometimes a gen sound coming from Cabin 1.

They, the owners are sure about it and thats enough for me.

pyrocasto · « **Reply #19 on:** October 24, 2005, 06:03:12 PM »

That's because the average speaker goes to 20,000 hertz. When you get that high it does make a difference. You could probably run solid to your subs though as they use less than 100 usually.

maker of toys · « **Reply #20 on:** October 25, 2005, 02:18:23 AM »

a couple of comments from someone who deals in a variety of powers over a variety of frequencies: (dc to microwave, nanoamps to >30kamps)

a)the gauge system of wire is such that, for low frequency or DC service, a given size of stranded wire is equal in initial bulk ampacity to the same gauge number of solid wire. However, as the effects of age, abuse and heat make themselves felt, solid wire wins hands down for current carrying capacity after about 3 years. almost without exception, apparatus that has solid conductors shows little or no age effects on tear-down, even after 10 or more years of service and neglect.

b) what looks like a solid mechanical and electrical joint on stranded wire is often anything but. this is frequently the case with plugs and recepticles, (even ones that are designed for stranded wire) and can lead to heating, insulation failure and (potentially) fires, not to mention the effects on efficiency. this usually manifests after time has had a chance to work its oxidation magic on an otherwise secure joint. tinning up the strands into a solid mass often prevents such problems. Properly crimped, the permanant compression-type connections seem to work well also, but screw-down connections on as-stripped stranded connectors are usually the culprits in intermittants and unreliablity.

c)initial connections in stranded wire often show advantages in resistance, because the conductors form themselves to the connection, giving more surface area contact. this same phenonenon makes the stranded connection nothing so much as a wick for moisture and contaminants. . . stranded copper, heat and humidity = rapid corrosion. I have removed 2/0 stranded cable from service indoors and had it literally crumble to green dust in my hands once I pulled it out of its clamps. once the end of a piece of stranded cable has gotten damp, it seems like only a matter of time before it fails due to corrosion.

-Dan

(just my 20 millidollars)

hiker · « **Reply #21 on:** October 25, 2005, 03:36:24 AM »

well you might what to try winding a few coils with stranded wire and see if you get more output--who knows might work great on the stators..but then again it would have to be insulated wire--with some kind of plastic covering..might melt with high amp output alts..maybe theres some thin insulated high temp wire out their..like for aircraft use.

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Author Topic: STRANDED WIRE > romex wire (Read 6041 times)