Which gauge wire

[Jimmy Higgins]

So I'm trying to replace a 100-ft length extension cord my parent(s) have that desperately needs to be replaced. The trouble is, I can't figure out which gauge I need. The wire is for a corded electric mower, which is 13 amps.

According to he Kobalt manual... modern science hasn't developed a 100-ft length cord capable of handing this amperage.

According to Home Depot... they say medium gauge 14 is fine.

And according to this site... 12 gauge is necessary due to the length.

Obviously, the higher the gauge, the more difficult it is to handle the wire when mowing my parents awful yard. If it was flat, it'd take 5 minutes. *sigh* Instead it is about 15 to 20 minutes, two groin pulls, and thirty curse words. I don't want a wire that makes it worse.

Are some 14 gauge wires "more" 14 gauge than others?

 

[Keith&Co.]

Claymores. One second, everything's at a uniform height. Grass, weeds, trees, landscaping, rocky outcrops, small cars, poorly-timed Jehovah's Witnesses....

 

[Poppa Popobawa]

Could you have several extension cords, joined end-to-end. You can get plastic enclosures to cover the joins, so that they can't come apart.



The cable can be assembled and dis-assembled to various lengths in this way.

 

[Toni]

Consider replacing the mower with one that runs on a rechargeable battery.

I am prejudiced because frankly I discovered long ago that for me, electrical cords were unwieldy. I also had an inordinate fear of someone accidentally running over the cord. So we ditched that lawn mower and used a gas one for years until the battery powered ones were available. Super easy to share and recharge.

No it’s NOT as cheap (by hundreds of dollars) as simply replacing the cord. But it WILL make your life easier.

 

[Jimmy Higgins]

I worked at a Marshalls as a teen and vacuumed the entire store. I absolutely mastered using long cords with aisles. So in an open area, no problem.

 

[Loren Pechtel]

According to Home Depot... they say medium gauge 14 is fine.

And according to this site... 12 gauge is necessary due to the length.

Note that on the Home Depot site you're right on the edge between 12 and 14. There's not a lot of difference in these two answers. I'd go with the 12. My 100' 12/3 extension cord is plenty flexible but the weight is quite noticeable when carrying it around.

Are some 14 gauge wires "more" 14 gauge than others?

Stranded carries slightly more current than solid. The effect is quite small at power line frequencies, though.

 

[Derec]

So I'm trying to replace a 100-ft length extension cord my parent(s) have that desperately needs to be replaced. The trouble is, I can't figure out which gauge I need. The wire is for a corded electric mower, which is 13 amps.

According to he Kobalt manual... modern science hasn't developed a 100-ft length cord capable of handing this amperage.

According to Home Depot... they say medium gauge 14 is fine.

And according to this site... 12 gauge is necessary due to the length.

Obviously, the higher the gauge, the more difficult it is to handle the wire when mowing my parents awful yard. If it was flat, it'd take 5 minutes. *sigh* Instead it is about 15 to 20 minutes, two groin pulls, and thirty curse words. I don't want a wire that makes it worse.

Are some 14 gauge wires "more" 14 gauge than others?

It's more about what sort of voltage drop is acceptable for the application. Some devices are more sensitive than others.

According to this, 14 gauge Cu wire has 0.505 Ω resistance per 100 foot of the cable. At 13 Amps, that's a voltage drop of 6.57V, or about 5%, which should not affect your mower much. However, you also lose 85.3 W to resistive losses (heating the cable).

Going up to 12 gauge, your resistance drops to 0.318Ω, you have 4.13V voltage drop and an 53.7 W extension cable heater.

Must be a rather small yard that they bought a corded electric mower instead of a gas one.

 

[Derec]

Stranded carries slightly more current than solid. The effect is quite small at power line frequencies, though.

Pretty close to zero as skin depth at 60 Hz in copper is ~8mm.

 

[Tigers!]

Claymores. One second, everything's at a uniform height. Grass, weeds, trees, landscaping, rocky outcrops, small cars, poorly-timed Jehovah's Witnesses....

We call that 'farmer's pruning'. 1" above the ground.

 

[Jimmy Higgins]

Could you have several extension cords, joined end-to-end. You can get plastic enclosures to cover the joins, so that they can't come apart.

View attachment 28400

The cable can be assembled and dis-assembled to various lengths in this way.

That doesn't address the physics of current though.

Claymores. One second, everything's at a uniform height. Grass, weeds, trees, landscaping, rocky outcrops, small cars, poorly-timed Jehovah's Witnesses....

For the last time Keith&Co, I'm not using claymores!

 

[ZiprHead]

Could you have several extension cords, joined end-to-end. You can get plastic enclosures to cover the joins, so that they can't come apart.

View attachment 28400

The cable can be assembled and dis-assembled to various lengths in this way.

No need to pay for those things. just do this:

 

[Derec]

Could you have several extension cords, joined end-to-end. You can get plastic enclosures to cover the joins, so that they can't come apart.

Bad idea. Shorter extension cords tend to be lower gauge. For example this cord is 16 gauge and rated for up to 13A, but two of them in series would not be recommended for 13A at all. You would really need to be careful about gauges if you go that route and really can't rely on current ratings.
Even worse if you want to connect 4 25' cords. Especially since there is some (small) additional resistance at the plugs.

 

[Derec]

No need to pay for those things. just do this:

Yes. Easy and works well.

 

[TV and credit cards]

Weight is a trade off. The lighter ones are thremoplastic insulation but are not as flexible. I like the thicker rubber insulated ones. They coil up nice. Unless you're one of those people who coils an extension cord between their thumb and elbow then just stop reading right now. Line loss isn't a concern for 120V. That's 12V vehicle battery stuff. The thicker the gauge the better but 14AWG is fine for 13A. I'd be concerned with it being abrasion resistant for the outdoors and being flexible so it is manageable. Oh and might as well go with something colorful for seeing it in the grass.

https://www.lapptannehill.com/resources/technical-information/portable-cordage-jacket-insulation-types

https://www.multicable.com/resources/reference-data/cord-designations/

https://www.powerstream.com/Wire_Size.htm
Powerstream is a great source of info. I did my dual battery setup in my truck using their info. Notice they talk about how conservative the UL ratings are for current carrying capacity.

Because then if you go to McMaster-Carr, the trusted source, you'll find for 13A, they list 14AWG cords.
https://www.mcmaster.com/extension-cords/extension-cords/length~1200inches/connection-type~straight-blade/number-of-outlets~1/end-type~socket/current~13amps/

Or if you just want to go to Lowe's, those Ridgid extension cords (orange w/grey stripe) are nice.

 

[steve_bank]

Look up a standard twisted multi strand wire table. It should give max amps. If you run max current for a wire it will warm up, so you van over specify.

Standard house wire I believe is 20 amps power breaker. Go to home Depo and somebody will pick the wire for you.

I doubt there are no industrial extension cords that can not handle 20 amps. Home Depo again or an industrial supply company on line.

 

[thebeave]

Look up a standard twisted multi strand wire table. It should give max amps. If you run max current for a wire it will warm up, so you van over specify.

Standard house wire I believe is 20 amps power breaker. Go to home Depo and somebody will pick the wire for you.

I doubt there are no industrial extension cords that can not handle 20 amps. Home Depo again or an industrial supply company on line.

The standard for residential wiring is 12 gauge wire for 20 amp circuits, and 14 gauge for 15 amp circuits. On that basis, given the long length of the extension cord, I would just go with 12 gauge for the cord.

 

[steve_bank]

Look up a standard twisted multi strand wire table. It should give max amps. If you run max current for a wire it will warm up, so you van over specify.

Standard house wire I believe is 20 amps power breaker. Go to home Depo and somebody will pick the wire for you.

I doubt there are no industrial extension cords that can not handle 20 amps. Home Depo again or an industrial supply company on line.

The standard for residential wiring is 12 gauge wire for 20 amp circuits, and 14 gauge for 15 amp circuits. On that basis, given the long length of the extension cord, I would just go with 12 gauge for the cord.

The problem with long lengths is the voltage drop across the wires.

Assuming a 20 amp rms current in phase with the voltage the peak current is around 28 amps. for a 1 volt drop across 200 feet,two wires, the resistance of the wire has to be less than 1 volt/28 amps = .036 ohms. or .036/200 feet = .00018 ohms/foot. Wire tables are in ohms/1000 feet.

 

[steve_bank]

You could always get a battery operated tool....

 

[steve_bank]

Here you go. 100 foot 20 amp indoor outdoor with ground fault.

https://www.amazon.com/20-amp-extension-cord/s?k=20+amp+extension+cord

 

[Loren Pechtel]

Here you go. 100 foot 20 amp indoor outdoor with ground fault.

https://www.amazon.com/20-amp-extension-cord/s?k=20+amp+extension+cord

Or in the select-a-size version:

https://www.costco.com/outdoor-50-ft.-extension-cord,-2-pack.product.100336733.html

(Note that this link may require logging in.)

2x 50' 12/3, lighted plugs. $50 if you order it, I think it's cheaper in the store.