Any way to "measure" wire gauge in power cord?

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To avoid voltage drop (and power loss) at startup, I want to make sure that the power cord to my 15 year old Craftsman table saw is 12 gauge (or upgrade it if it is not).
There are no markings on the cord and no reference in the manual. The saw is long discontinued so Sears is no help.
So is there any simple way of determining whether cord is 12 gauge or not?
Thanks
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blueman wrote:

...
12 AWG --> ~0.081" 14 AWG --> ~0.064"
So, 12 is a little over 1/16", 14 is about 1/16" diameter. Enough difference if the connection at either end is visible to tell easily.
That said, what horsepower is the motor rated/current draw on the motor plate? If the cord is the OEM-supplied one, it's unlikely it's so undersized as to be discernible difference in changing it out...
Assuming it's a dual-voltage motor, you could always go to the 240V connections and cut current draw in half...
--
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Do these numbers apply to stranded too? (I believe the power cord is stranded)

My concern was just that at startup (or when bogging down) it will draw more than the rated 13A/1.5HP so that maybe moving to 12 gauge would help me out given that the total cord length is about 15 feet.

I would like to do that but the manual says "It is wired for operation on 120 volts, 60 Hz alternating curent. IT MUST NOT BE CONVERTED TO OPERATE ON 230 VOLTS". Now someone mentioned in another thread that this may just be due to the fact that the switch only switches one leg and that everything would be ok if I swapped in a DPDT switch to switch both phases.
But I don't have any manual for the motor itself and don't know what needs to be rewired.
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blueman wrote: ...

Yes, gauge is gauge...
...

Not really as somebody else already said, in 15-ft the difference in voltage drop between the two is going to be in the mV range.
See other response for more likely things that could actually make some difference.
...

Any dual-voltage motor will have lead diagram with it on the motor or in the connection box or similar. If it doesn't it's not likely it is. Even if it were, it wouldn't provide more power, only cut the current draw.
If there were anywhere in the circuit that was a limiting factor, it would be the overall circuit being 15A and 14ga therefore. If you're running it on a 20A/12ga supply circuit, again the short length of power cord just isn't going to be enough to make any discernible/practical difference.
--


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Then with stranded there's less copper to make up for the extra air. Air will be present because of the (space-filling) inefficiency of ROUND things.
[snip]
--
Mark Lloyd
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Mark Lloyd wrote:

...
Well, actually, there is a very small difference that does account for it, but it's not of much importance for any practical purpose...typical specs for stranded vis a vis solid--except for the last column which I backed out of the previous three columns of data, these are from the American Insulated Wire catalog.
(AWG NUMBER PVC NYLON APPROX. APPROX. OR OF INSUL. JACKET OUTSIDE Conductor KCMIL) STRANDS THICK. THICK. DIAMETER DIAMETER (INCHES) (INCHES) (INCHES) (INCHES) 14 Solid .015 .004 .104 .066 12 Solid .015 .004 .121 .083 ... 14 19 .015 .004 .112 .074 12 19 .015 .004 .131 .093 ...
--
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Close, but not exactly. Stranded wire of a particular gauge will have the same amount of wire cross-section area to carry current as solid wire of the same gauge. Because there's some air spaces between strands when they are packed as tightly as possible, the overall diameter of the bundle will be slightly larger for the stranded wire, but only by about 10%.
You can calculate the size increase yourself fairly easily:
Perhaps the simplest stranded wire that's still well-packed has 7 strands, one in the centre and 6 around it. This gives hexagonal packing, with the centre strand touching all 6 outer strands, and each outer strand touching two neighbours as well as the centre strand. If the diameter of one strand is 1 unit, the diameter of the whole bundle (measured in the direction that gives the largest measurement) is 3. With 7 strands, the wire has 7 times the cross-sectional area of one strand, and will carry 7 times the current. A *solid* wire with the same current capacity and resistance would be sqrt(7) = 2.645 units in diameter, while the 7-strand wire is 3 units in diameter - about 13% larger.
(On the other hand, if you measure across the "flats" of the stranded wire, with the caliper jaws touching two wires each, the measured diameter is only 2.732 units, or only 3% larger than a solid wire of the same metal cross section. So it matters how you measure).
In a wire with many more strands (e.g. welding cable), the outside becomes rounder, so the diameter measurement doesn't vary significantly. And the "extra" diameter for stranded approaches the ratio of the area of a hexagon to a circle inscribed in it, which is sqrt(12)/PI, or about 1.103. In other words, the many-strand cable is 10% larger than the equivalent solid wire.
    Dave
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snipped-for-privacy@cs.ubc.ca (Dave Martindale) writes:

Cool! Thanks for the detailed explanation.
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Is that data for solid or stranded? He did mention "cord" which implies stranded conductors.
If a train stops between stations, and the man with the hat gets off. He's out there in the middle of no where hollering "all aboard". Now, that's a stranded conductor.
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On Sep 3, 10:04am, "Stormin Mormon"

If a train stops between stations, and the man with the hat gets off. He's out there in the middle of no where hollering "all aboard". Now, that's a stranded conductor.
How can you call him stranded if there's train right next to him?
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Sigh. One in every group. You're right, of course.
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Stormin Mormon wrote:

Jeesh...don't you read the rest of the thread????
The gauge is based on total of conducting material, stranded or solid. Yes, there's a slight diameter increase of stranded over solid to account for the geometry but it's essentially immaterial in the actual dimensions as far as determining whether one is talking of 12 vs 14 ga.
Is that good enough?????
--
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I assume that you don't trust Sears to have installed to proper size cord for the unit in the first place, right?
If you can disconnect the cord at the saw end (unplug it first!), possibly in a junction box near the switch, you should be able to determine the size by using any device that is marked with wire gauge sizes, such as a wire stripper with pre-set holes/markings.
On the other hand, if you are going to disconnect it to check it, you might just as easily replace it with a known 12 gauge cord.
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Well, it is a 15A motor, so "technically" 14 gauge would be OK, but I'm getting some bogging down so I thought maybe I could get a few ounces more of power by upgrading to 12 gauge if it is not already. On the other hand if it is already 12 gauge, seems like it would be a waste to replace it.

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blueman wrote: ...

...
The drop in as short a cord as the typical cord is likely so little as to be significant even if it is 14ga.
As noted in earlier response, if it were a dual-voltage motor moving it to the 240V will cut the draw (but not make any real difference otherwise).
15A would be 3/4-1 hp which is (as is typical for contractor saws) on the underpowered side for a 10" saw.
Probably you'll get more satisfaction by improving the quality of the sawblade and possibly going to a thinner kerf blade and ensuring blades are quite sharp and the saw is well aligned than in the minimal benefits of the cord gauge.
That said, if must stay on 110V and if it were by chance only a 14ga cord, I'd certainly not recommend against changing it out but I would still doubt it will help the problem significantly.
--
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wrote:

For only 15 feet of wire, it would not make any noticiable differance if you went from 14 to 12 gauge wire. YOu could go to #6 wire and not notice any differance in your saw.
.
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wrote:

One other thought, how far is the saw from the main breaker box ? It could be the drop in the wiring going to the receptical. .
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A saw that bogs down needs a sharp blade. Or the right blade. Look over your stock, take the dull ones to a good sharpening shop and you won't have to fuss over power cords. HTH
Joe
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If the saw is stationary, please consider hard wiring it with Romex. Skip the plug and socket. I suspect that a plug and socket are only good for some number of amps before they start being inefficient.
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On Sep 3, 9:05am, "Stormin Mormon"

You ought to be able to determine the wire gage with an accurate postal scale One that reads to 0.01 gram would be right. Maybe 0.1 gram if you want to waste some wire. Cut equal lengths of known and unknown wires. Strip insulation and weigh. If the weights are the same, the gage is the same. HTH
Joe
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