Electrical Wire vs Speaker Wire

[noercarr]

I'm wanting to wire up some 12v led lights and small 12v appliances (water pump and dc fridge under 7A). I can score some speaker wire for 50% off right now from the clearance section of the hardware store. Any reason I could not use "speaker wire" vs standard electrical wire for low voltage applications?

Note: Not asking about specific AWG sizes. I'm aware of the charts of amps and runs to determine AWG.

 

[AffableCurmudgeon]

I would not. Not sure what the characteristics and voltage ratings of the insulation are for the speaker wire.

Would it conduct the current? of course; Would there be any arcing buy using it at a voltage that the insulation is not rated for? I don't know and don't want to find out the hard way.

 

[wyliesdiesels]

The speaker wire/insuation would need to be rated for the voltage..

For DC electricity, make sure to NOT use twisted conductor wire, such an extension cord, as this can create an additional drain on a battery if you use one.

 

[rlitman]

I would not. Not sure what the characteristics and voltage ratings of the insulation are for the speaker wire.

Would it conduct the current? of course; Would there be any arcing buy using it at a voltage that the insulation is not rated for? I don't know and don't want to find out the hard way.

Speakers operate above 12V all the time.

The only concern I'd have is that speaker wire is often fine stranded aluminum, and is pretty crappy. If you KNOW that it is all copper, then great. But if not, I'd stay away.

 

[SuzukiGS750EZ]

For led's sure, for appliance applications that pull way more current I would be cautious. Can you explain where the wires will live and what the game plan is? I normally just buy a roll of stranded wire of the proper gauge and it lasts quite a while. LEDs have almost no current draw

 

[American Locomotive]

Speaker wire is typically very finely stranded to reduce skin-effect losses at high frequency. Speaker wire is frequently aluminum, sometimes even copper plated aluminum - so keep that in mind as well.

As long as you use the proper gauge, I don't see why you couldn't use it. My only beef with speaker wire is that it looks kinda hack, and the insulation seems to be rather soft.

 

[Bert_]

I use thermostat wire or lamp cord quite a bit for led tape light.

For DC electricity, make sure to NOT use twisted conductor wire, such an extension cord, as this can create an additional drain on a battery if you use one.

Anything to back that up? I have never heard that and can't think of any reason off the top of my head why that would be a problem.

 

[wyliesdiesels]

I use thermostat wire or lamp cord quite a bit for led tape light.



Anything to back that up? I have never heard that and can't think of any reason off the top of my head why that would be a problem.

Just my experience.

When i lived off grid, my FIL used an extension cord to power a DC RV fridge powered by our battery bank. We noticed a noticeable drain on the batteries even with the fridge off or unplugged. Turns out it was the extension cord...

 

[American Locomotive]

Nothing to do with the cord being twisted conductor. The cord would have had an internal short somewhere. DC doesn't care about anything being twisted. There's no inductance, no changing magnetic field, no nothing.

 

[Max]

Twisted wire doesn't matter to DC. Your extension cord had a partial short or other issue that was specific to that cord.

For DC, the conductors need to be rated to carry the current that you draw. The OP said 7 A, which will be too high for smaller gauge speaker wire. You wire should say the gauge on the spool, and you can look up what current it is rated for online. Similarly you can look up the resistance per foot of wire, and then using you max wire length and max current you can figure out the voltage drop. (voltage drop = current x resistance)

As another poster noted speakers are routinely over 12V so I don't expect insulation rating to be an issue. However, if the wiring is going inside a wall, the wire should say
"in-wall" or plenum on it. This is the fire rating if the insulation, which some people care a lot about and others ignore...

Max

 

[exmaxima1]

Speaker wire is typically very finely stranded to reduce skin-effect losses at high frequency. Speaker wire is frequently aluminum, sometimes even copper plated aluminum - so keep that in mind as well.

It's finely stranded mainly for flexibility. Unless the strands are individually insulated from each other it makes no difference regarding "skin effect"----the current will flow on the outermost surface unless you make each strand have its own outermost surface. It is very common to use a form of Litz wire for high frequencies, where a bundle of individually insulated wires are twisted/weaved and terminated together only at their ends.

Years ago it was a standing joke in the audio industry about Monster Cable and their ads about their wire where different thickness strands supposedly handled different frequencies. Pure BS, but it sold lots of overpriced wire. The owner of Monster Cable had a fleet of expensive sports cars!

 

[rlitman]

It's finely stranded mainly for flexibility. Unless the strands are individually insulated from each other it makes no difference regarding "skin effect"----the current will flow on the outermost surface...

Right. And the outermost surface of copper coated aluminum is still copper. In the case of speaker wire, and other high frequency transmissions (such as ethernet), the copper coated aluminum handles the signal just fine, because the signal doesn't reach into the aluminum (ok, bass audio will). Now try to carry DC on it, and you start to see resistance issues (which is why CCA wire is no good for PoE). Not to mention the fact that aluminum has other issues, such as being brittle.

Yes, the fineness of the strands is all about flexibility. Aluminum is stiff and brittle, and needs finer strands to keep from showing off its ugly side on a flexible cable. But finer strands are also more prone to corrosion.

tl;dr Just make sure the wire hasn't got any aluminum in it.

 

[Marctrees]

rlitman and American Locomotive said something that many are not aware of..

Most of my 61 years "Speaker Wire" split zipcord style.. was like always solid copper.

Now, the same looking and application stuff is often AL that is obvious to see..

The thing to watch out for is the wire that is AL PLATED to look like copper.

Like from Amazon for example, lot of that plated stuff is not obvious.

It will be cheaper, so those that do not know will grab it and be fooled.

Makes me think of those damn cheap toilet floor bolts... Look like traditional non rust Brass, but actually steel.

Marc

 

[Max]

Umm, no. Audio frequencies (~20 KHz) are not high frequency and any skin effects are minimal at the most.

And while it may be out there, most of the cat 5/5e/6 cable I've seen has been solid copper and not aluminum or stranded copper wire. What makes ethernet cable work at high speeds is the twist pattern used for both the wire pairs and the cable as a whole.

Max

 

[American Locomotive]

Umm, no. Audio frequencies (~20 KHz) are not high frequency and any skin effects are minimal at the most.

Skin depth at 10KHz for copper is 0.65mm, so anything larger 16 AWG will be affected. At 20KHz, the skin depth is only 0.46mm, so anything larger than 19-20 AWG will experience it.

But as others mentioned, it turns out that it doesn't really matter, as uninsulated stranded wire effectively acts as one large wire.

 

[justsam]

I would use Class 2 rated wire. Most of the flat, 2 conductor "speaker wire" is not.

 

[Max]

Skin effect is not some quantum kind of effect where no current flows once you exceed it. Instead, it's a gradual effect where still 98% of the current is contained within 4x the skin effect depth.

Using your number (which I haven't checked) of 0.46mm for 20 KHz, this means that if the radius of the wire is less than or equal to 4x the skin depth then you have a 2% or less resistivity increase. A radius of 1.84mm is 7 gauge wire, hence the use of the term "minimal".

Max

PS. https://en.wikipedia.org/wiki/Skin_effect for more math than you probably want...

 

[SuzukiGS750EZ]

We've complicated a simple matter.

Get a thicker gauge wire and you'll be fine. Do you know what they're offering? And will you power this from a battery or inverter?

 

[James-W]

Why not just use the correct wire and forget about the speaker wire? OK, so it costs a few dollars more. So what? You will have the right wire for the job and you have no worries. I am no different, I like to save a couple dollars when I can. But there are times when you are just better off getting the right stuff to do the job. Personally, I think this is one of those times.

 

[Max]

> We've complicated a simple matter.

Of course we have! This is garage journal.

Get some 12 AWG speaker wire and you'll be fine for your 12V wiring. This assumes that you are not running very long lengths of wire. 12 AWG is roughly 1.6 ohms per 1000', and you want to draw 7A, so at 1000' you'd be dropping 11.2V in your wiring. But at 100' you'd only be dropping 1.1V, and 50' would be just a bit over a half volt.

If it was me, I'd add a fuse or circuit breaker in series at the battery or power supply that gives you your 12V. I'd also use in-wall rated wire, and as others have noted I'd avoid Al wire.

Max

 

[wyliesdiesels]

Nothing to do with the cord being twisted conductor. The cord would have had an internal short somewhere. DC doesn't care about anything being twisted. There's no inductance, no changing magnetic field, no nothing.

Twisted wire doesn't matter to DC. Your extension cord had a partial short or other issue that was specific to that cord.

For DC, the conductors need to be rated to carry the current that you draw. The OP said 7 A, which will be too high for smaller gauge speaker wire. You wire should say the gauge on the spool, and you can look up what current it is rated for online. Similarly you can look up the resistance per foot of wire, and then using you max wire length and max current you can figure out the voltage drop. (voltage drop = current x resistance)

As another poster noted speakers are routinely over 12V so I don't expect insulation rating to be an issue. However, if the wiring is going inside a wall, the wire should say
"in-wall" or plenum on it. This is the fire rating if the insulation, which some people care a lot about and others ignore...

Max

i guess we had 3 bad extension cords? cause the next 2 did the same thing. strange

 

[MrSurly]

My thoughts on 12VDC wiring; a key consideration is what are you using to power the 12V? My tape lights (gun safe, etc) are powered with a wall-wart type of supply that is current limited to less than 2A. As long as that’s the case I don’t have any serious concern about the wire or it’s insulation. Now, let’s say you are using a battery back up or solar system, the potential for significant amperage would concern me more. Drop in some one or two amp fuses and the fire possibility should be mitigated; the wire quality would be less of an issue?


Sent from my iPhone using Tapatalk

 

[nh_yota]

Skip the speaker wire and use lamp cord.

 

[WaterBoyz]

Speaker wire is typically very finely stranded to reduce skin-effect losses at high frequency. Speaker wire is frequently aluminum, sometimes even copper plated aluminum - so keep that in mind as well.

As long as you use the proper gauge, I don't see why you couldn't use it. My only beef with speaker wire is that it looks kinda hack, and the insulation seems to be rather soft.

Contradiction here.

American Locomotive is giving advice on finely stranded wire.

 

[jismay]

I've used 10 & 12 GA speaker wire from Fry's Electronics all the time for 12v power cables for things like solar, 12v fridges, etc. Its nice 2 conductor wire which is perfect for a 12V power lead. 12GA copper wire is 12GA copper wire.

 

[kbuhagiar]

12GA copper wire is 12GA copper wire.

True (to a certain extent) - but it's the insulation used in conjunction with the conductor (not the conductor alone) that determines the proper application.

 

[theoldwizard1]

i guess we had 3 bad extension cords? cause the next 2 did the same thing. strange

"Cordage" is twisted, but not very tightly. I would be surprised that running DC through it would have any loss other than the normal loss due to resistance.

 

[American Locomotive]

"Cordage" is twisted, but not very tightly. I would be surprised that running DC through it would have any loss other than the normal loss due to resistance.

It doesn't matter if the cord was twisted like a pretzel inside. Twisted wire will not "drain batteries". I'll go hook my DC power supply up to 400 feet of cord right now, and will not measure a single nanoamp of current flowing.

 

[walta]

Anything I put in my walls I would want rated for no less than 600 Volts lots of “speaker wire ” will be rated. If the wire does not have a voltage and AWG label on the wire I saw pass and find wire with a rating.


I also would want a fuse at the source that is rated to blow before this wire would melt and start a fire.


Walt

 

[CJ7VFR]

I use thermostat wire or lamp cord quite a bit for led tape light....

I used brown 14 gage lamp cord to hook up my LED tape lights that are on top of my bar mirror and on the underside of the bar top to shine light down onto the countertop of the bar.

The LED transformer that came with the tape lights had a chart that showed what gage wire to use for different lengths and distances you might mount the lights from the transformer.

The wire that came with the LED tape lights was 20 gage speaker wire (red insulation with one side having a black stripe on it), and it said this gage wire was good for up to 10 feet away from the transformer before you had any noticeable voltage drop. I ended up using some lamp cord I had because in my application, which was a run of about 12 feet from the transformer, I didn't want to have any voltage drop to the lights.

It worked great, the brown insulation on the lamp cord blends in with the bar and mirror better than the red insulated wire does, and the lights have no loss of brightness due to voltage loss.

Jim